Bio-Based Building Materials - Proceedings of ICBBM 2025

The increasing focus on sustainable construction has driven interest in 3D printing technology, particularly in developing bio-based cementitious composites that incorporate agricultural by-products. This strategy aims to improve the performance of printable materials while promoting an innovative solution for eco-friendly building practices. In this context, this paper investigates the effect of rice husk bio-aggregates on fresh properties, mechanical strength, and microstructure of 3D printable bio-based cementitious composites. A reference mortar was prepared with 0–0.6 mm natural sand and 0.38 water-to-cement ratio. Different volume fractions of rice husk were used (15%, 20%, and 25%). Rheological properties over time were assessed using fresh compression tests, while mechanical properties were evaluated through uniaxial compression tests, on both mold-cast and printed samples. Microstructure and porosity were analyzed using optical microscopy. The results demonstrated that rice husk increases the green strength, critical time, and structuration rate of the composites. Mechanical tests indicated that the addition of rice husk negatively affects compressive strength, due to an increase in porosity and debonding between the rice husk and the matrix. The findings indicate that the rice husk volumetric fraction should be carefully selected to optimize the rheological properties without excessively compromising the mechanical performance of cementitious composites for 3D printing.

With the ongoing advancement of 3D printing technology in the construction sector, the requirement for materials with optimized fresh and mechanical properties is becoming more critical. Natural fiber-reinforced mortars can be an effective solution by enhancing material’s printability. This work evaluates the effect of cellulose microfibers (CF) on fresh and hardened properties of 3D printable mortars. A reference mortar was prepared with 0–1 mm sand and 0.4 water-to-cement ratio, and three volumetric fractions of fibers were used: 2.5, 7.5, and 12.5% by mortar volume. Fresh-state properties were studied using flow table and fresh compression tests. Physical and mechanical tests were also conducted to assess the effect of fibers on the hardened state properties. A robotic 3D printer was used to assess mortar printability. Fresh state results demonstrated that CF significantly increased rheological properties over time, enhancing thixotropic behavior. 3D printing tests showed that CF improved buildability, although limited extrudability and shortened the printing open time. Additionally, CF increased 28-days mechanical strength of mortars; however, they also enlarged capillary water absorption, which could impact durability. The results underscore the potential of CF to modulate fresh and hardened mechanical properties of 3D printable mortars for construction applications.

In the face of current environmental challenges and the ongoing increase in energy consumption, the use of locally available bio-based materials emerges as a key solution to achieve environmental objectives [1]. The transportation of these materials constitutes a significant portion of their environmental impact [2], making their local availability essential to reduce the environmental impact associated with transportation. Plant aggregates stand out due to their high hygroscopicity, allowing them to absorb significant amounts of water. However, this adsorption phenomenon within porous networks can generate internal stresses on the solid skeleton, leading to volumetric deformations. Moreover, adsorption/desorption cycles can negatively affect the structural integrity of materials, causing cracking, degradation, or plastic deformations. These interactions also depend on the size and shape of individual pores, generating pore-scale forces that impact the overall adsorption mechanisms. Theoretical studies, such as those addressing the impact of pore size distribution on deformation induced by sorption in porous materials [3], have helped to better understand these mechanisms. This experimental work fits into this framework by exploring the interactions between the microstructure and the hygroscopic performance of bio-based materials. It specifically focuses on miscanthus, a resource available in the Hauts-de-France region, and aims to fill the gaps identified in the literature. The study relies on a thorough analysis of the microstructure of miscanthus aggregates using high-resolution tomography and characterization of their hygroscopic properties. The results allow to understand the interaction phenomena between microstructure and hygrothermal properties, focusing especially the poral network of the skeleton of bio-based miscanthus building materials.

Using thermal insulating materials like expanded polystyrene (EPS), polyurethane (PU), and mineral wool are an effective way to reduce electricity consumption. However, their use results in millions of tons of waste annually and is associated with potential health risks. Within this context, bio-based insulation materials have gained growing interest, as they can replace those plastics and store CO2. Foam forming is a process that enables the production of sustainable and lightweight fiber materials by combining water, fibers, and foaming agents. This work aims to evaluate the ability of wood dust to generate foam without the use of a foaming agent, as well as the stability of the resulting material at fresh state. To achieve this, foams were generated at mixing velocities of 500, 1000, 1500, 2000, and 2500 rpm. The optimal mixing speed was then selected to produce foams with consistencies of 0.05, 0.10, 0.15, 0.20, and 0.25. The foam generation ability was assessed by measuring the mixture volume every 10 s, while the stability was evaluated by monitoring the decrease in foam volume at one-minute intervals. It was found that the foam volume increased with the mixing speed. Following the same tendency, higher mixing speeds led to increased foam stability. When the mixture consistency was varied, the results revealed that lower consistencies resulted in a larger foam volume. Although this study is preliminary, it shows the possibility for producing a stable foam without foaming agents.

The construction sector is among the most polluting industries worldwide and seeks to achieve decarbonization through the use of sustainable materials. In this context, innovative construction materials such as bio-concrete—developed with biologically sourced aggregates—are being explored. This study aims to develop and evaluate the fresh-state properties (slump test and incorporated air content) and hardened-state properties (capillary water absorption and compressive strength) of bamboo bio-concretes produced with fine (FB) and coarse (CB) bio-aggregates. A total volumetric fraction of 30% was used, along with a cementitious matrix comprising Portland cement, metakaolin, and fly ash, with a water-to-binder ratio of 0.30. The results demonstrated that bio-concretes with higher coarse bio-aggregate content exhibited up to 44.62% lower capillary water absorption and achieved modulus of elasticity values up to 39.75% higher compared to mixtures containing only FB. Additionally, direct water exposure was found to negatively impact the mechanical performance of the material, leading to reduced strength and Young's modulus. All mixtures were found to be workable and moldable, with the inclusion of CB resulting in less porous mixtures, provided that a minimum proportion of FB is maintained in the composition.

Technological advancement and the increase in the consumption of natural resources have generated a growing volume of waste, especially in the forestry sector. The production of agglomerated panels from wood waste and the use of vegetable resins, such as those derived from castor oil, emerge as sustainable alternatives to mitigate the environmental impacts caused by the improper disposal of these materials and the development of environmentally friendly materials. The objective of this study was to evaluate the feasibility of producing agglomerated panels of wood particles from waste of angelim-ferro (Dinizia excelsa), cupiúba (Goupia glabra) and cedar with caferana (Cedrela spp and Erisma uncinatum), using vegetable polyurethane resin based on castor oil. Water absorption, flexural rupture (MOR) and screw pullout tests were performed to characterize the physical-mechanical properties of the panels. The results indicated that the panels produced presented densities ranging between 0.75 and 0.92 g/cm3, classifying them as medium and high density. The values of flexural strength and screw pullout met the Brazilian (NBR), American (ANSI) and European (EN) technical standards, demonstrating potential for application in ceiling panels. It was observed that the use of these wood wastes, combined with vegetable resin, is a viable and sustainable alternative to produce construction materials, contributing to the reduction of environmental impacts.

Excavated soil containing non expansive clays can be used to develop low-carbon 3D-printable materials. To further enhance the moisture sensitivity and other physical properties, geopolymer containing blast furnace slag (GGBS) and fly ash (FA) can be an excellent stabilizer. However, due to rapid hydration in GGBS-rich geopolymers, the open printing time is too short to construct large-scale 3D-printed elements. This research explores the addition of sucrose to introduce controlled retardation in 3D-printable geopolymer-earth materials (GP-E). By adding sucrose at 1.0% by weight of the binders (GGBS + FA), the open printing time of GP-E can be prolonged by 4–5 times compared to that of control (no sucrose). The longer open printing time is attributed to slower hydration kinetics leading to longer flow retentions and a controlled development of plastic viscosity and yield stress. Deprotonation of sucrose in alkali (NaOH in this case) increases the negative charge and form complexes with metal ions (Na+, Ca2+), leading to better dispersion and particle repulsion in the fresh stage. The filling effect of clay and its dissolution to form zeolitic products synergistically balances the repulsive forces due to sucrose, leading to superior shape stability and 5 times higher buildability during printing. In summary, the research demonstrates a strong potential of sucrose as a bio-based set controller for printing large-scale 3D-printable geopolymer stabilized earth structures.

Clay-based building materials are promising solutions for contemporary construction with low environmental impact. New processes and mix designs are currently being developed to address increasing demand. Thus, 3D-printed clay-based building materials are at the intersection of technology and sustainability trends. However, the durability of clay-based materials remains an issue as they are very sensitive to water. Liquid water leads to the collapse of clay-based structures, and bio-stabilizer identification remains a challenge. In this paper, different stabilizers and application modes against liquid water were investigated for 3D-printed clay. Gels extracted from Aloe Vera and Opuntia Ficus are shown to delay water imbibition and collapse of clay structures under full immersion. A bio-stabilizer for clay-based structures has been developed to help create a water-resistant wall with a bio-sourced binder.

3D concrete printing (3DCP) is a significant advancement in modern construction, enabling tailored rheological and mechanical properties for additive manufacturing. Optimal flowability, static yield strength, and mechanical performance are essential for successful 3DCP, ensuring workability during extrusion and stability for subsequent layers. Incorporating sustainable materials like fly ash enhances the environmental appeal of 3DCP, making it a promising green alternative to traditional methods. This study examines the impact of key mix components on the rheological and mechanical properties of 3DCP to develop optimized compositions balancing flowability and stability. A factorial design approach was used to systematically vary cement content (550–650 kg/m3), fly ash (10–20% of cement), superplasticizer (0.2–1.0 kg/m3), and water (295–315 kg/m3). All mixes made with 3 kg/m3 of sisal fibres. This method improves optimization efficiency by identifying effective combinations and reducing experimental trials. Rheological properties were evaluated using slump flow, cone penetration, and cylindrical slump tests, while compressive and flexural strength tests assessed mechanical performance. Statistical models identified the water and binder content as the most critical factor influencing rheology. Fly ash improved fluidity and strength in conventional concrete but had limited benefits in 3DCP due to water absorption. Superplasticizers enhanced fluidity and reduced water use but required careful balancing to prevent adverse effects. The factorial design further refined these findings, efficiently identifying parameter interactions critical for achieving optimal 3DCP performance.

France has hundreds of thousands of hectares of vineyards, being considered one of the world’s largest producers of grapes and wine. However, its production results in tons of grapevine prune waste. Burning this waste produces high amounts of greenhouse emissions while crushing and disposing of it in the soil can spread diseases to the vineyards. Therefore, it is necessary to explore new alternatives for the material’s application. A potential application of this material is as aggregate in bio-based concretes. This type of concrete is commonly known to have interesting thermoacoustic insulating and humidity regulation properties. However, there are still challenges to overcome before commercial application. The main ones are the presence of components which affect the binder’s hardening, such as phenols and sugars, and the aggregate’s high-water absorption compared to conventional mineral aggregate, which can affect the mixing/casting (associated to rheology) and strength gain of concretes. Therefore, as a preliminary step for the development of vine shoot concrete, this study aims to investigate the influence of varying effective water and aggregate water contents, considering the aggregates absorption, on the rheological and compressive strength characteristics of vine shoot concretes. The findings indicate that pre-saturation of the aggregates resulted in a 2.5-fold increase in compressive strength for the different water contents tested. Also, a reduction in mixing energy and more homogeneous concretes were observed. In addition, higher total water contents resulted in lower maximum torques, apparent viscosity, mixing energy and compressive strength.

Bamboo holds significant potential to establish itself as a pioneering material in the European construction industry, mainly due to its high ecological sustainability and remarkable mechanical properties. Despite its advantages and the growing acceptance of bamboo as a construction material, significant knowledge gaps remain regarding the mechanical behavior of bamboo under various loading conditions and orientations due to the non-homogenous structure of bamboo culms. Additionally, for successfully integrating bamboo into the European construction sector, it is crucial to study the mechanical characteristics of locally grown bamboo from Europe, which often exhibit slender diameters. This study therefore investigates the bending behavior of European bamboo culms through experimental analysis. Specifically, ten Italian Phyllostachys edulis culms are subjected to full-culm four-point bending tests, capturing deformations by photogrammetric inspections. The experimental setup and the measurement methodologies are described in detail, followed by the execution and analysis of the bending tests. Subsequently, modulus of elasticity is derived for cyclic and non-cyclic loading based on the photogrammetric data. The results of the bending tests are compared with existing research on Phyllostachys edulis culms. In summary, this study contributes to applying bamboo as a building material in Europe by highlighting the potential of using local resources and facilitating knowledge transfer for the European construction industry.

Biobased concretes, such as flax or wood concretes, are ecofriendly materials that benefit excellent hygrothermic and acoustic properties. They are usually combined with a loadbearing wooden structure, but recent studies show that those concretes can reach masonry-like compressive strengths, which suggests their potential use for structural elements. However, the lack of data on its delayed mechanical behavior is an issue to their development. This article describes the study of the drying and shrinkage, in controlled environments (22 ℃, 50%RH), of two types of biobased concrete: flax concrete and wood concrete. The water loss and shrinkage of concrete samples are monitored for one month under autogenous and drying conditions. The strength of the concretes, and the cement paste alone, are also tested at different ages. Results show that wood concrete is the most suited for structural use thanks to its higher mechanical strength. Besides, the lower water absorption capacity of wood aggregates makes wood concrete less demanding in water during its fabrication than flax concrete. Finally, the shrinkage of wood concrete is 3.5 times lower than flax concrete after one month.

Vegetable fibers appear as a promising and sustainable alternative for reinforcing cementitious plates in wall-systems applications. Vegetable fibers, such as sisal, offer some advantages over synthetic ones, such as high availability, low cost, renewability, and biodegradability, in addition to exhibiting excellent physical and mechanical properties. Seeking to understand the potential application of such materials in civil construction, this study investigates the mechanical performance of cementitious plates reinforced with 5% long aligned sisal fibers. To improve the durability of the composite, 50% of the cement consumption in matrix was replaced by 40% metakaolin and 10% fly ash to avoid fiber degradation by alkaline attack. Tensile strength tests in flexion were performed in two distinct conditions, according to the guidelines of NBR 15498 (2021): saturated and in equilibrium with laboratory conditions. The plates tested in equilibrium showed an average strength of 22.31 ± 4.56 MPa, while those tested in the saturated condition recorded an average of 19.07 ± 2.68 MPa. The results highlight the potential of these sisal-reinforced cementitious plates as an effective alternative for wall-systems applications in building construction, such as internal partitions, rendered facades, eaves, among others.

To reduce CO₂ emissions in cement production, Limestone Calcined Clay Cement (LC3) emerges as a promising alternative. However, its rheological behavior is influenced by the morphology of the clays used, including their specific surface area, roughness, and flocculation tendency, which often lead to rheological loss. This study evaluates three clays with varying kaolinite contents: a low-kaolinite clay (7% kaolinite), a clay derived from red mud (37% kaolinite), and a high-kaolinite clay (43% kaolinite). Mortars were assessed through mechanical strength tests and workability. The results showed that 37K and 43K clays exhibited significant rheological losses due to their rougher particle morphology and higher specific surface areas. Despite this, both clays demonstrated pozzolanic activity and reactivity after calcination, acquiring the minimum mechanical strength required for structural applications, albeit lower than reference mixtures. In contrast, the 7K clay displayed superior flowability due to its smoother particle morphology and reduced specific surface area but had reduced mechanical performance. Additions of ornamental stone waste (OSW) improved the flowability of high-kaolinite mixtures. This study underscores the critical influence of clay morphology and mineralogy on LC3 performance, balancing workability and mechanical properties.

This study conducts a systematic literature review on connections in bamboo structures, exploring technological advancements and innovations, emphasizing mechanical performance and challenges. Following the PRISMA guidelines and the PICO framework, the research was structured using the STROBE guidelines for the rigorous selection of articles from the Scopus and Web of Science databases. The results reveal a significant improvement in ductility across various types of connections, the influence of screw diameter and spacing in bamboo culms, and the favorable performance of fillers in enhancing connection stability. Additionally, innovations such as 3D connections and the use of biocomposites are explored. However, the study highlights critical gaps, such as the need for standardized techniques and broader experimental investigations to assess performance in diverse application scenarios. The presented systematic review contributes by mapping existing knowledge, identifying challenges, and emphasizing the need for greater investment in research and technical standards to promote the broader use of bamboo as a structural material.

Ageing and vulnerability of civil engineering structures are major concerns for stakeholders in the construction sector today, ranging from engineers to end-users. Moreover, the building sector in France is responsible for 44% of energy consumption and the annual emission of over 123 million tonnes of carbon dioxide, while also contributing to the depletion of non-renewable resources. These challenges make this sector a key driver in combating climate change and advancing the energy transition. One potential solution lies in the use of Fabric Reinforced Cementitious Matrix (FRCM) composites made from vegetal fibres, recognised for their low environmental impact, to strengthen existing and new structures. This article focuses on investigating the global and local mechanical behaviour of these composites in order to promote their adoption in construction. To achieve this, a multi-scale approach has been adopted, ranging from the analysis of the textile-matrix interface to the study of the FRCM composite as a whole. Flax, jute and carbon textiles were selected for this experimental study. The pull-out test was used to analyse the behaviour of the textile-matrix interface, while the direct tensile test combined with the Digital Image Correlation (DIC) technique was used to characterise the overall performance of the FRCM composites. The study investigated the influence of textile pre-impregnation in the mineral matrix, the addition of short flax fibres and the type of textile on the textile-matrix bond and cracking mechanisms in the FRCM composites. The results showed that the textile-matrix bond properties have a significant effect on the mechanical response of the composites, highlighting avenues for optimisation of both materials and structures.

Developing composites using fabrics made from natural fibers represents a sustainable alternative for civil construction. Ensuring adequate interaction between the components is essential for the proper performance of the composite, preventing premature failure. This study analyses the interaction between jute and sisal fabrics with a cementitious matrix. The adhesion between natural fibers and the cementitious matrix is directly influenced by factors such as the attack of free hydroxides from cement, impurities from the production process, and water absorption capacity of the fibers. The fibers were treated using a cyclic hornification process to mitigate these effects. Additionally, a self-compacting cementitious matrix was used, in which part of the clinker was replaced with fly ash and silica fume. The interaction between fibers and matrix was evaluated through pull-out tests, allowing for comparing results obtained with treated and untreated fibers. The results indicated that sisal adhesion stress was exceeded, leading to the fibers being pulled out of the matrix. Conversely, jute fibers exhibited superior adhesion to their tensile strength, resulting in filament rupture before significant slippage occurred. Hornification treatment positively influenced the adhesion results. Treated fibers demonstrated reduced water absorption capacity, which minimized dimensional variations compared to untreated fibers, contributing to a more stable interaction with the cementitious matrix.

Bamboo bio-concrete (BBC) consists of a cementitious matrix that binds together plant biomass particles as bio-aggregates. Bamboo imparts characteristics such as lightness, low thermal conductivity, and reduced carbon footprint to the material. However, since bamboo is a combustible material, it is crucial to understand its behavior in fire situations. Therefore, this work aims to evaluate the fire reaction properties of bamboo bio-concretes and assess post-fire residual uniaxial compressive strength. For this purpose, bio-concretes with 30%, 40%, and 50% bamboo bio-aggregates, in volume, were produced, with a matrix composed of Portland Cement V-ARI, Fly Ash, and Metakaolin in mass proportions of 40:30:30, respectively. The water-to-binder ratio used was 0.35, and 2% calcium chloride was added as a set accelerator. The fire reaction properties were evaluated using a Mass Loss Cone Calorimeter with a heat flux of 50 kW/m2. Experimental results indicated that the heat release rate and total mass loss increased as higher fractions of biomass were incorporated into the samples. For BBC 30, BBC 40, and BBC 50 samples, the peak heat release rate values were 12.7 kW/m2, 13.7 kW/m2 and 16.0 kW/m2, respectively. Based on the results, even with 50% biomass content, the bio-concretes are non-combustible materials and do not contribute to the development of a fire.

The construction sector is a significant contributor to environmental impacts, like climate change and natural resource consumption, driving the search for more sustainable solutions. In this context, this study aimed to produce and characterize physically, mechanically, and environmentally solid blocks of pressed wood bio-concretes by partially replacing cement (CP V-ARI) with 50% and 70% of soil. All mixtures had a fixed volume fraction of wood shavings of 60%. The effect of that replacement was investigated through uniaxial compression and capillarity water absorption. A cradle-to-gate carbon-oriented life cycle assessment was conducted considering all materials and processes involved in the production of the mixtures, with a specific methodology for biogenic carbon accounting. The results indicated that partially replacing cement with soil reduced the density of the blocks compared to the reference block. Regarding compressive strength at 28 days, the block with 50% soil achieved 3.51 MPa, while the block with 70% soil reached 2.31 MPa, making both suitable for non-load-bearing masonry. The reference block, on the other hand, achieved a compressive strength of 6.45 MPa, qualifying it for use in structural masonry. Blocks containing 70% of soil exhibited a higher capillarity water absorption rate than those without soil. Concerning the LCA, wood shavings biogenic carbon was the main contributor to lower emissions due to high biomass content.

Over the past decades, bamboo has increasingly gained attention as a sustainable construction material, through its rapid growth, naturally optimized shape, high mechanical properties, and significant environmental benefits. However, despite these advantages, the use of bamboo in its natural form for structural applications remains limited, partly due to insufficient knowledge of connection behavior, which is crucial for ensuring the long-term reliability and performance of bamboo structures. This article provides a comprehensive review of the key factors to consider in the design of structural bamboo connections and discusses the existing connection classification methods used as guidelines by designers. By synthesizing findings from the literature, our research aims to identify the key parameters interacting with the connection design process, focusing on the anatomical, geometric, and mechanical properties of bamboo, the mechanical requirements of the structure design, and the building methods. A critical analysis of Janssen's classification of bamboo connections, based on force transfer modes and later refined by Widyowijatnoko, is presented. Finally, we discuss the identified research gaps and emphasize the need for integrated design approaches supported by guidelines to support the broader adoption of bamboo in construction.

The use of alternative materials in civil construction has shown significant growth, driven by the demand for more sustainable solutions. In this context, this study investigates the structural behavior of small walls built with Extruded, Pressed, and Fired Ceramic Blocks (BCEPQ). These blocks present themselves as a promising alternative for the sector due to their potential to optimize the construction process by reducing execution time, minimizing waste, and mitigating rework, as they are interlocking blocks. Despite their potential advantages, the properties and behavior of these blocks are not yet fully consolidated in the literature. Thus, this study aimed to contribute to the understanding of their characteristics by evaluating the structural performance of small walls subjected to static loads. Experimental tests were conducted in the UENF laboratories using the Digital Image Correlation (DIC) technique. This methodology allows, through the capture and processing of images in specialized software, the identification of deformation patterns over time, providing detailed information about the structural behavior during loading cycles. Additionally, a numerical model was developed using the ANSYS 2024 R1 software to compare the experimental results with computational simulations. The model enabled the analysis of fundamental parameters such as deformations, compressive strength, and failure modes, contributing to the validation and efficiency of numerical modeling applied to this type of material.

This paper analyzes the impact of four types of biobased aggregates (hemp, bamboo, reed and rapeseed) and their orientation (parallel or perpendicular to the compaction direction) on the mechanical properties of biobased concrete. Digital image correlation (DIC) was used to study mechanical deformation at two scales: that of the composite material and that of the interfacial transition zone (ITZ) around the aggregates. The results show that biobased concrete oriented parallel to compaction are stiffer, but more susceptible to damage at low strain rates as low as 2%. Hemp concrete, the strongest concrete, undergoes limited vertical displacement but shows more pronounced damage. Bamboo concrete, on the other hand, although denser, has the lowest mechanical performance. Finer aggregates, such as reed, offer better mechanical properties thanks to better adhesion and compatibility with the mineral matrix. Finally, local DIC analysis reveals zones of concentrated deformation for parallel-oriented aggregates, resulting in weaker affinity and buckling failure in this configuration. It is therefore recommended to orient the aggregates perpendicular to the compaction direction for better load distribution and optimal energy dissipation

Fire resistance and the properties of structural materials under high-temperature conditions are crucial aspects in designing safe and durable buildings. Structural masonry, an essential component in civil construction, is not immune to the adverse effects of extreme heat, as evidenced in fire incidents and other situations involving intense flame exposure. Understanding how masonry responds to such conditions is vital to ensuring structural safety and, consequently, protecting human lives and property. This research aimed to investigate the safety of extruded, pressed, and fired ceramic blocks (BCEPQ) exposed to high temperatures and how these conditions affect their physical and mechanical properties. The study relied on both experimental and numerical analyses to identify alternatives and standards that enhance safety and prevent potential failures. The methodology involved the experimental analysis of masonry prisms subjected to temperatures of 30 ℃, and 600 ℃ for 30 min in industrial furnaces, followed by compression testing using a hydraulic press. The results showed that BCEPQ performed well under the tested conditions, withstanding compression loads and maintaining stability at elevated temperatures. These findings underscore the ceramic blocks’ efficacy and potential applications in scenarios requiring enhanced fire resistance and structural integrity.

The mechanical behavior of Natural Textile Reinforced Mortars (NTRMs), made with flax textile and sustainable mortar matrix (Portland cement + metakaolin + fly ash + lime), are investigated in this paper. Both treated and untreated samples of flax textile are deeply characterized, including all the individual components (i.e., yarn, thread, and fabric). Then, flax fabric-TRMs are used for strengthening brick masonry walls, with and without the addition of the mortar matrix. As a result, treated flax fabric TRMs demonstrate superior mechanical performances and reduced crack openings compared to those untreated. Furthermore, walls strengthened with treated flax fabric layers exhibit improved strength and fracture toughness, unlike those with untreated fabric. Thus, if biomaterials are properly treated, they can effectively reinforce existing masonry structures in seismic zones.

Hempcrete, a bio-composite material known for its excellent thermal efficiency, is gaining traction in the construction industry as an environmentally friendly alternative. However, the binder component used in the hempcrete has long been a debated issue among researchers. This paper aims to explore the influence of SCMs on the thermal and mechanical performance of hemp-lime composites. The study utilized lime-based binders incorporating slag, which is an industrial by-product, to evaluate its effect on hempcrete specimens. Hydrated lime was partially replaced with slag in proportions of 20%, 30%, 50%, and 100%, with lime binder hempcrete serving as the reference sample. The binder-to-hemp ratio was maintained at 1:1 by weight, yielding an average density of 190 to 200 kg/m3. The hemp shives were also ground finely to minimize their impact on the results and reduce variability. The findings indicate that incorporating slag into the binder enhances both the mechanical strength and thermal resistance of the material while reducing its heat capacity. However, a higher slag proportion in the binder was found to affect compressive strength inversely. This outcome offers new insight into a better understanding of binder combinations in hempcrete.

The construction sector plays a crucial role in addressing current environmental challenges, particularly by reducing greenhouse gas emissions. Traditional concrete structures significantly contribute to CO₂ emissions, necessitating the development of low-carbon alternatives. Among these, wood-based concrete, such as the TimberRoc technology from CCB Greentech, appears as a promising solution. This bio-based composite combines wood particles with a cementitious binder, offering both structural and environmental benefits.However, unlike conventional concrete, wood-based concrete exhibits substantial variability in its mechanical properties due to the anisotropic nature of wood. This variability influences critical characteristics such as the elastic modulus, which varies depending on the orientation of the wood particles and the direction of the applied stress. A thorough understanding of these mechanical behaviors is essential to optimize the structural applications of wood-based concrete.This study aims to analyze the anisotropic mechanical behavior of a TimberRoc wood concrete formulation, focusing on variations in its elastic modulus under compression, four-point bending, and direct tension. By comparing these results with those of existing bio-based materials, we seek to improve the predictability and reliability of wood-based concrete for structural applications.

The reduction of carbon footprint towards sustainability in the construction sector demands innovative construction techniques and novel and bio-based building materials to optimize the building process and make it more sustainable. This study evaluates experimentally the dynamic thermal performance on hardened lime-cement mortars with Phase Change Materials (PCM) and Cellulose Fibers (CF) for 3D printing applications. Four material’s design strategies were followed to reduce carbon footprint: partial substitution of cement by air-lime, addition of a Phase Change Material (PCM) to increase thermal energy efficiency, nanoclays to improve material printability and Cellulose Fibers (CF) to enhance extrudability and enlarge durability. A mortar mixture with 20% of PCM was selected to produce three types of specimens: cast in the mold plate, 3D-printed plate and 3D-printed truss. A multilayer enclosure system with a thermal insulation layer plus a mortar specimen was tested using a climate chamber to simulate dynamic cooling and heating cycles, ranging 15 - 30ºC. The experimental results showed that the manufacturing procedure did not modify the high thermal efficiency of the material, while a truss cross-section element largely increased energy efficiency of the enclosure system.

Earth-based building materials provide a pathway to mitigate the carbon footprint of the construction sector. The use of these materials is still nowadays limited because of their weak mechanical properties, high shrinkage and the time required for drying. This paper proposes to investigate the synergic approach which consists in coupling a 3D printed earth-based open matrix core wall system to a hygroscopic insulation material: moisture transport from this hygroscopic insulation material to earth-based printed material aims to reduce the amount of water entrapped into the printed soil, and thus increase the drying rate of the earth and its so-called ‘buildability’ property at the same time. A choice has been made to focus in this study on a matrix core insulated wall system composed of clay as printed material and on wood fibers as hygroscopic insulation material. Apart from the service-life properties provided by the coupling of both materials, this work mainly aims to assess, first and foremost, the potential of dry wood fibers filling to stiffen printed soil-based structure during 3D printing process.

In the realm of construction, particularly in residential settings, a significant portion of energy consumption is attributed to the provision of essential thermal comfort through heating and air conditioning systems. To address and optimize this energy usage while mitigating excessive consumption, thermal insulation stands out as an effective technology for achieving desired indoor comfort levels.The core concept behind thermal insulation is the careful installation of insulating materials selected for their energy-efficient properties, thereby minimizing heat loss or gain and enhancing energy self-sufficiency. This paper aims to offer a comprehensive review of the existing literature concerning sustainable thermal insulation solutions derived from locally available and abundant natural fibers, specifically tailored for the construction industry. Additionally, it explores the evolution of various forms of natural fiber-reinforced polymer composites.The findings from various research efforts confirm the significant advancements achieved in the field of building insulation through the utilization of locally sourced natural fibers.

The construction industry urgently requires sustainable building materials. Mycelium-based composites (MBCs), a class of bio-based materials grown from fungal mycelium on organic substrates, have emerged as a promising insulation solution. A key challenge in MBC development is in understanding the inter-species variability and its role in thermal performance. Fungal species influence thermal properties and MBC viability, however, studies quantifying differences between a large range of species are lacking. Additionally, the accuracy of thermal conductivity measurements varies between methodologies, with some approaches being unsuitable for anisotropic bio-based materials including MBCs. Addressing these uncertainties is critical, as optimising fungal species requires accurate, and repeatable, measurement methods to facilitate validation and meaningful comparison of inter-laboratory data.This study addresses these gaps by evaluating the thermal conductivity of MBCs produced using 20 fungal strains across 19 species, employing both transient (Hot Disk) and steady-state (Heat Flow Meter) methods. The research investigates interspecies variability in thermal conductivity, the impact of density on thermal conductivity, and methodological differences.Thermal conductivity measurements revealed significant interspecies variability, demonstrating the influence of fungal selection on insulation properties. While the specimens consistently exhibited thermal conductivity values comparable to traditional insulation materials (average thermal conductivity measured using the Heat Flow Meter was (0.0405 ± 0.0004) W/mK), transient methods systematically overestimated values by an average of 51% relative to steady-state measurements, influenced by material anisotropy and density.These findings underscore the importance of measurement methodology in evaluating bio-based materials and provide practical insights into species selection for scalable, sustainable insulation materials.

The use of bio-based materials offers an eco-friendly solution to reducing building energy consumption. However, their adoption remains limited due to a lack of understanding of their hygrothermal performance compared to conventional materials. This study seeks to address these challenges by thoroughly analyzing the hygrothermal characteristics of bio-based materials across three scales: composite material, wall, and building scales. At the composite material scale, the hygrothermal properties of various bio-based concretes and insulation boards are systematically reviewed. At the wall scale, the hygrothermal behavior of wood-cement concrete walls is examined under diverse climatic conditions. Finally, at the building scale, the energy performance of structures utilizing hemp concrete is compared with conventional buildings, focusing on heating and cooling energy consumption. This multi-scale investigation aims to advance the practical implementation of bio-based materials in sustainable construction and contribute to the broader adoption of eco-friendly building practices.

Biomaterials derived from plant waste are becoming a major topic of research as substitutes for conventional thermal insulating materials. However, many of these materials lack acoustic studies to evaluate their performance. The objective of this study is to assess the acoustic behaviour of four different biomaterials, bound with two different types of natural binders, and to perform a comparison between them. The materials under study are rice husk, rice straw, sunflower stalk, and Posidonia oceanica. The selection of these materials was based on their local availability and ease of procurement, as well as previous comparisons with other accessible materials. The bio-binders used are xanthan gum and arabic gum, chosen for their good results in binding these materials. Before conducting the acoustic tests, a physical characterization of the materials was carried out, along with a thermal conductivity test to evaluate their performance as thermal insulators. The acoustic tests performed were the acoustic absorption tests conducted using the Kundt’s tube method. For this, samples of each material were prepared in varying thicknesses, and the thickness yielding the best result was tested again. The results provide an initial understanding of the acoustic performance of these materials, as well as a comparison between them.

The use of biobased contributes to reducing greenhouse gas emissions, energy consumption and depletion of natural resources by exploiting alternative renewable aggregates. Several studies in the scientific literature have focused on the design of these bio-based materials and the characterization of their properties. The results are in accordance with thermal and hydric performance of these materials for hygrothermal building comfort. Nevertheless, their use remains limited, with questions about their long-term behavior and their performance under implementation and exposure to real climatic conditions. In the case of energetic rehabilitation, these materials are added with existing different materials. It is therefore essential to study the behavior of these biobased materials in the case of multi-layer walls and in the real use conditions to show their efficiency.The objective of this work is to evaluate the hygrothermal behavior of the multilayer wall using different straw bio-based materials developed for building insulation. The experimental building has been designed to simulate the case of external energy renovation. Blocks of straw bio-composites with three different compositions were fixed to each façade of classical concrete blocks with wood fiber panel for comparison purposes. A coating based on lime and limestone sand was then implemented to protect the bio-composite and provide an aesthetic effect. For on- site characterization and monitoring of measurements, the experimental building was instrumented with temperature, humidity and heat flow sensors in the core of the insulation materials, interior, exterior and at the insulators-concrete block interface respectively. The results showed that there is greater humidity in the core of the insulation materials than outside in winter and a smaller difference in summer. This behavior highlights the hygroscopic nature of the bio-based materials. It is also important to note that the behavior of the straw-based materials and wood fibers was similar, with no significant effect of composition.

Vegetal wools are highly porous materials made of vegetal and polymeric bicomponent fibers. They feature high-level multifunctional properties, such as sound absorption and hygrothermal regulation. However, despite their attractive properties, they suffer from poor low-frequency sound absorption for thin panels (less than 5 cm thick). A solution to this problem can be found in meta-material methods. Unfortunately, very little research has been done on this subject with applications for bio-based materials.Moreover, it seems relevant to use the specificities of vegetal wools, such as the polydispersity of their fiber radii, for these acoustic optimization approaches involving meta-material methods.To meet this challenge, a state-of-the-art has been carried out to identify suitable analytical modeling methods to simulate their acoustical behavior, and to optimize it. A first optimization consisted in implementing the meta-material concept of double porosity into a resistive hemp wool layer. Combined with a multiple layers configuration, this approach significantly improved the acoustic absorption of hemp wool panels.To go further, this work aims at comparing different analytical approaches to account for fiber radius polydispersity. Vegetal wools present a large range of fiber radii, and most studies consider a mean radius for simulations, with arithmetic or quadratic averaging methods. However, these approaches may overestimate the role of fibers with larger radii, which, for the example of static airflow resistivity relying on the thinner fibers, can inaccurately represent the physics. This work investigates different ways of averaging the radius probability distribution of vegetal fibers to improve the accuracy of analytical estimations.

The novel application of silica sol-gel to modify the hygroscopic properties of the mycelium-cellulose composites (MCC) was successfully demonstrated in this study. The MCCs are a promising low embodied carbon and sustainable construction material that can be produced from industrial cellulosic waste. The MCCs have comparable thermally insulative properties to fossil-based alternatives; however, the MCCs suffer from high water uptake rates. Two hydrophobic sol-gel coatings were produced with different silica sources, tetraethyl orthosilicate (TEOS) and sodium silicate (SS), and these were compared in this study. It was found that the SS sol-gel MCC had less water uptake with a change in mass of 3.8% in lower humidity environments (0–45% RH), whereas the TEOS sol-gel had a lower change in mass of 26.9% from (45–95% RH) compared to the MCC which had a change in mass of 8.2% and 48.5% respectively. This has shown that the novel use of sol-gel technology and mycelium-cellulose composites can decrease the water uptake of the MCC by 44.56%, which is a crucial first step for the wider utilisation of MCCs.

This review explores advancements in sustainable bio-based materials, focusing on acoustic panels derived from natural materials. There is increasing interest in shifting modern acoustic strategies away from petrochemical and resource-intensive materials, toward renewable, eco-friendly, non-chemical alternatives, particularly for non-structural applications like acoustic treatment. These applications prioritize soundproofing and insulation without compromising structural integrity. Key evaluation metrics for characterizing bio-based materials for acoustic purposes are presented. Frequency-specific Acoustic Absorption Coefficients are evaluated for all materials. Additionally, when data is available, the weighted Acoustic Absorption Coefficient and Noise Reduction Coefficient are included to provide a more comprehensive assessment of acoustic performance. This ensures the understanding of panel performance in listening spaces in relation to human hearing and acoustic treatment solutions for varied applications. Natural fibers such as flax, wood, hemp and animal wool are assessed for their potential as acoustic bio-based materials, with a focus on leveraging locally available resources considering Québec, Canada. Properties such as porosity, microstructure, texture, and density are critical for classifying and optimizing the characterization of bio-based materials. In the context of reducing the embodied carbon footprint of construction materials, bio-based materials offer a versatile and sustainable alternative for acoustic applications, demonstrating promising acoustic and environmental performance. This article aims to provide a foundation for more advanced research in bio-based materials for vibration control, soundproofing and sound insulation.

The use of natural reinforcement as a substitute for conventional reinforcing fabrics within Textile Reinforced Mortar (TRM) technology is an increasingly addressed topic in research. This choice was made to improve the sustainability of such reinforcement interventions on structures. The main problems encountered with respect to this solution are inherent to the characteristics of the natural fabric itself: in fact, the latter presents on the one hand mechanical characteristics suitable for structural use, in particular for masonry; on the other hand, aspects such as variability in physical and mechanical characteristics and durability represent “weak” points to be investigated and addressed.The study carried out deal with these issues, applying the polymer coating technique to the natural fabric/yarns. However, to avoid compromising the sustainability of the intervention, rather than using conventional polymers (mainly epoxy resin), bio-polymer (Poly-Lactic Acid, PLA) has been chosen. As a matter of fact, although coating/impregnation is a commonly used technique in TRM to improve the characteristics of the reinforcement, the possibility of using bio-polymers has not been effectively addressed yet in the literature.The physical and mechanical characterization of the fabric elements thus treated was then carried out. One of the analyses concerned the study of the bond behaviour between the impregnated fabric-yarns and the lime-based mortar with which the latter will have to interact. Two phases of pull-out tests were then carried out, designing specific test configurations for the required needs, and in these the bond between the fabric and the matrix was recorded by varying different parameters (different impregnation concentrations, different anchoring lengths, different type of natural yarns).The results obtained represented a failure mechanism between impregnated cord and mortar mainly related to the interaction between the matrix and the PLA present on the surface of the cord. In general, however, the behaviour of the fabric presents promising characteristics for use within TRM systems.

A significant number of existing buildings worldwide are made of masonry and, as they were built in the past, they do not generally meet the current standards in terms of structural/seismic safety and energy efficiency. Moreover, buildings, including masonry ones, are responsible for a significant share of energy demand and Green-House-Gas (GHG) emissions. Therefore, there is an urgent need to come up with efficient and effective techniques capable of enhancing both structural safety and thermal insulation of existing buildings. Besides some isolated attempts to come up with a integrated approach to target both aspects, the scientific community generally addresses seismic safety and thermal insulation as two separated and this is also the case of practitioners.In this context, the present paper summarizes the preliminary results of the IntegraTRM project which aims at formulating an efficient and sustainable solution for coupled thermal and seismic upgrading of existing constructions. More specifically, it aims at formulating the composition of a composite Textile Reinforced Mortar (TRM) system characterized by an “optimized” performance in terms of both structural strengthening and thermal insulation. The formulation of the TRM system under consideration is based on the use of “environmentally-friendly” constituents: a significant fraction of recycled aggregates, coming from construction and demolition waste, are considered for the mixture proportioning of the mortar matrix; vegetable fibers and fabrics are being employed to achieve both mechanical resistance and thermal insulation potential.

This study explores the development of eco-efficient cementitious compo-sites using Magnesium Oxy-Sulfate (MOS) cement matrices reinforced with core-shell textile structures and lignocellulosic fibers. By integrating bio-based reinforcements with multiscale architectures and employing accelerated carbonation curing, the research enhances sustainability by reducing clinker usage and CO₂ emissions while improving mechanical performance and durability. PET/sisal and flax-based core-shell textiles were designed to optimize tensile strength and ductility. Bio-based epoxy resin treatments im-proved fiber-matrix adhesion, enhancing energy absorption during pullout tests. The reinforced MOS composites exhibited flexural strengths exceeding 7 MPa, meeting Brazilian standards for Type A panels for exterior applications. Accelerated carbonation curing promoted Hydrated Magnesium Carbonates (HMCs), improving density and reducing porosity; however, pro-longed curing reduced mechanical strength due to the consumption of critical MOS cement phases. Durability tests, including 50 wet-dry cycles, confirmed material stability under simulated weathering. These findings demonstrate the potential of MOS composites as sustainable alternatives to clinker-based materials, emphasizing the need to optimize carbonation curing parameters for balancing eco-efficiency and mechanical integrity.

Lime-natural pozzolan based mortars are very common in historic buildings, as they provide adequate moisture removal from the masonry and are stronger and more durable than air lime mortars. Furthermore, lime-natural pozzolan mortars represent a more environmentally friendly option than lime or cement-based mortars. In some cases, animal fibers, especially goat and bovine, have been used in mortars in the past. When designing and developing mortars for the repair and restoration of historic buildings, compatibility requirements with historic mortars and masonry must be met. For this reason, The aim of this paper is to investigate the effect of the addition of horsehair, goat hair, bovine hair and pig hair on the physico-mechanical and microstructural properties of lime-pumice mortars. The investigated fibers were added to the mixture at 0.25%, 0.5% and 1.0% by weight of binder and compared with the untreated mortar. The addition of all animal fibers required a greater amount of mixing water to maintain the same flow rate of fresh mortar, which particularly affected the initial strength and porosity of the mortars. All mortars with fibers were more frost resistant than the reference mortar and significant changes also occurred in the capillary action of water through the mortars. Goat hair, in particular, appears to be very promising for improving not only the physical and mechanical properties of lime-pozzolan mortars, but also the transport of water from damp masonry and the durability of mortars.

Shells are curved architectural structures with rigid surfaces and small thickness, widely used for covering large spans without intermediate supports. Commonly applied in urban furniture in ferrocement, their use has been limited due to corrosion issues in the steel mesh. This work presents a new concept of cementitious shells using reinforcement with layers of natural jute fabric. Produced through a hand layup process, cylindrical shells with four fabric layers and two different arc lengths were subjected to three-point bending tests to evaluate mechanical behavior and failure modes. The effect of arc length on shell deformation was numerically assessed using Karamba software. The results demonstrated that the addition of jute fabric enhances the shell's load-bearing capacity due to stress redistribution after the formation of a plastic hinge and the first crack in the matrix. This stress redistribution leads to the development of new cracks on the upper surface of the shell. The arched geometry increases the load-bearing capacity of the shells compared to flat shells. However, cylindrical shells with a height of 150 mm exhibited lower bending stiffness and lower maximum bending load than shells with a height of 75 mm, due to the increased eccentricity.

Amazonian fibers are gaining attention for their potential use as sustainable materials in construction due to their natural abundance, renewability, and eco-friendly properties. However, their application often depends on understanding their intrinsic properties and how NaOH treatment can modify them. This study focuses on characterizing the Tucum, an Amazonian fiber, evaluating its physical, chemical, and mechanical properties, and assessing the effects of different treatments. The untreated fiber and its treated counterparts underwent a series of analyses, including thermal, structural, and morphological evaluations. The results demonstrated that it was possible to characterize several key properties, such as tensile strength, thermal stability, and water absorption. Moreover, significant changes were observed in the fiber's structure and behavior after treatment, highlighting the influence of the applied process. These findings provide valuable insights into optimizing natural fibers for construction applications, promoting their broader use in sustainable engineering practices.

In recent years, the scientific community has shown increasing interest in the development of self-healing cementitious matrices. To understand the current state of research on this topic, a systematic literature review (SLR) was conducted on self-healing concrete in Latin American databases. The methodology involved an exhaustive search of articles published in the Scielo, Latindex, Redalyc, and Dialnet databases between 2018 and 2024. Through Google Scholar, 220 documents were identified, and after applying exclusion criteria, 15 scientific articles were selected. The results indicate that microorganisms, particularly Bacillus subtilis, are the most widely studied within a self-healing cementitious matrix. However, the outcomes are influenced by several variables, such as the microorganism concentration, application method, type, and condition of the cementitious matrix, among others. Therefore, further experimental studies are necessary to gain a more precise understanding of the behavior of these variables in the development of self-healing concrete.

Civil construction is one of the most environmentally impactful industries, accounting for approximately 5% of global carbon dioxide (CO2) emissions, primarily due to the cement production process. To mitigate this impact, it is essential to diversify the materials used in the sector, as the demand for cement is unlikely to decrease significantly. Incorporating vegetable fibers into the cementitious matrix offers a sustainable solution to replace synthetic fibers, addressing the inherent low tensile strength of cement-based materials. These fibers act as reinforcement by controlling crack propagation. Jute fibers were selected for this study due to their promising properties, including tensile strength, and Young's modulus, with average values of 250 MPa and 30 GPa, respectively. The research focuses on developing mortars reinforced with jute fibers, using a matrix composed of 50% cement, 20% fly ash, and 30% metakaolin. The addition of pozzolanic materials to the matrix aims to partially replace cement, improving the mortar's durability and reducing deleterious chemical reactions within the matrix. For this study, mortars with varying fiber percentages and lengths were tested and evaluated through physical and mechanical characterization. Compared to the reference sample, the fiber-reinforced mortars exhibited increased water absorption and void index due to higher porosity introduced by the fibers. Despite the increase in matrix porosity and the reduction in compressive strength compared to the reference, the fiber-reinforced mortars demonstrated an average improvement of more than 50% in the flexural strength of the composite. Regarding toughness, the reinforced composites presented an average toughness around 16.7 times greater than that of the reference sample. This indicates a significant capacity to absorb and dissipate energy during impacts or shocks. These results highlight the potential of cementitious composites reinforced with jute fibers as a promising and sustainable alternative for the construction sector, particularly for use in masonry coatings.

Bamboo, due to its physical and mechanical properties, has significant potential for incorporation in civil construction. However, when subjected to specific loads or certain conditions, bamboo may become vulnerable, which is why technical standards recommend filling the bamboo with mortar or similar compounds for reinforcement. This study aimed to evaluate the mechanical behavior of bamboo when filled with cementitious composites reinforced with sisal fibers. For this purpose, bamboo specimens of the Bambusa vulgaris species were collected from the State University of Feira de Santana. After drying, the bamboo culms were cut into 20 cm lengths, both with and without nodes. The bamboo was filled with mortar and sisal fiber-reinforced composites, and four-point bending tests were performed on the described types of bamboo. The results showed that bamboo filled with the reinforced composite had a higher load capacity compared to unfilled bamboo and bamboo filled with mortar. The load versus deformation curves indicated that the post-cracking behavior of bamboo filled with the reinforced composite exhibited multiple peaks after the maximum load, due to the collaboration of the fibers in the mix, which was consistent with the failure type of this specimen. In contrast, bamboo filled with mortar showed fractures at the support points. It can be concluded that the incorporation of the fiber-reinforced composite significantly improves the bending behavior of bamboo.

Integrating natural fibres as reinforcement in geopolymer concrete has gained significant attention due to their potential to enhance mechanical properties, especially in increasing tensile strength. This study explores three approaches to incorporating natural fibres into geopolymer matrices to optimize flexural and tensile performance. To test the different configurations and approaches, tiles with 120 $$\,\times \,$$ × 120x20 mm were used. The first approach employs discrete Miscanthus fibres as dispersed reinforcement. The second investigates the application of natural jute fibre nets in geopolymer concrete tiles, testing two grid types with surface densities of 120 g/m $$^{2}$$ 2 and 220 g/m $$^{2}$$ 2 in four configurations. The third approach uses 1 mm diameter flax yarns to reinforce geopolymer tiles. Different spaces between the yarns were considered (10mm, 15mm and 20mm). Experimental results reveal that all natural fibre -reinforced configurations enhance flexural strength compared to the unreinforced control mixture. Additionally, the advantages and limitations of each fibre type and configuration are critically analyzed, providing valuable insights into sustainable and high-performance geopolymer concrete design.

This study investigates two key aspects of sand concretes: (1) the impact of constituent types—silica sand and crushed sand—on their physico-mechanical properties, and (2) the influence of plant fiber reinforcement (DISS fibers) at varying percentages on their mechanical and thermal performance. To achieve these objectives, a systematic experimental approach was adopted. Initially, sand concretes with varying proportions of silica sand and crushed sand were developed to determine the optimal formulation. Subsequently, the best-performing formulation was reinforced with DISS fibers at different dosages.The results revealed distinct workability characteristics based on the sand type. Silica sand-based sand concretes exhibited firm workability, while those made with crushed sand were highly fluid. Balanced formulation comprising 50% silica sand and 50% crushed sand provided optimal plastic workability.In terms of mechanical performance, all sand concrete formulations demonstrated superior tensile strength compared to traditional concretes, with the 50%-50% formulation exhibiting the highest mechanical performance. Moreover, the inclusion of DISS fibers significantly enhanced the thermal properties of sand concretes, reducing thermal conductivity and effusivity as the fiber content increased.These findings underscore the potential of hybrid sand formulations and plant fiber reinforcement to improve the performance and sustainability of sand concretes.

In the transition towards a circular economy, the use of waste and byproduct materials in construction is gaining attention for its potential to enhance sustainability. This study examines the mechanical properties —including flexural and compressive strengths— of various ternary matrices, known as limestone calcined clay cement (LC3), developed with residue fillers and metakaolin. Subsequently, laminated textile-reinforced mortar (TRM) panels were fabricated using 100% Portland cement (PC) and an optimized LC3 matrix (containing ≤ 50% PC). These TRM panels, structured as sandwich-like laminates, were reinforced with nonwoven fabrics made from textile waste (TW) fibers sourced from garment industries. Results revealed that the mechanical properties of LC3 matrices were comparable to conventional PC, achieving flexural and compressive strengths exceeding 10 MPa and 120 MPa (at 28 days), respectively. Both LC3 and PC-based TRM plates demonstrated flexural-hardening behavior, achieving flexural strength of greater 10.0 MPa and energy absorption above 5.0 kJ/m2 (at 7 days). The study highlights that reducing PC content to ≤ 50%, replacing limestone powder with filler wastes, and utilizing recycled fibers as reinforcement can meet the performance requirements of cement panel boards for limited structural applications, contributing significantly to sustainable construction practices.

The concept of fiber reinforced concrete (FRC) was invented to reinforce concrete with a wide range of fibers such as steel fibers, glass fibers, synthetic fibers, polyethylene fibers or carbon fibers. The addition of superplasticizers (SP) has enabled to gradually reduce W/B ratio and improves binder dispersion, which in turn improves mechanical properties of the cementitious matrix. In this study, two different types of fibers were mixed. It was studied the workability of cementitious mortars and the impact of fiber length and dosage. Natural fibers such as hemp, miscanthus and flax fibers were mixed with FIBRAFLEX fibers. FIBRAFLEX fibers are amorphous metallic fibers resistant to corrosion and chemical attacks. Two different sizes of fibers (FF13E7, FF15E0) were mixed with natural fibers in six different formulations. The composition of the granular skeleton and fibers have an impact on the workability of different formulations, and this aspect was studied using the slump cone. For the analysis of the cementitious matrix and the fiber/matrix interface, tomography was used to analyze the microstructure, observe the natural fiber/FIBRAFLEX fibers/cementitious matrix interaction and analyze material heterogeneity and fiber tortuosity within the cementitious matrix. Mechanical strength tests at 1, 7 and 28 days using 3-point bending and compressive strength tests were carried out, enabling us to gain a better understanding of the material characteristics obtained via tomography tests. This study investigates how fiber affects mechanical properties.

Natural fibers are widely used ecological materials, mainly in civil construction, where they can be inserted into cement matrices, among other applications. One of these natural fibers is coconut fiber and its use in cement composites presents several benefits. The fibers provide better mechanical properties to concrete because they have higher tensile strength and modulus of elasticity than the cement matrix. The fibers absorb the load, increasing the residual strength of the composite. As disadvantages, they have greater variability of physical and mechanical properties, lower durability, low resistance to microbial attacks and low resistance to moisture. However, these problems can be minimized by modifying the fiber surface through chemical and physical treatments. Thus, this article aims to analyze the performance of cement composites with coconut fibers subjected to mercerization and hornification treatments through flexural tensile strength testing and scanning electron microscopy (SEM). From the results found, it was verified that the mercerization treatment applied presented better results when compared to the hornification treatment, presenting a rougher, cleaner and more uniform surface, which helped in the interface with the composite. In addition, it also presented a higher proportionality limit and residual resistance, which for application in cementitious composites is interesting because in the post-cracking behavior the fibers serve as a bridge for transferring stresses through the cracks.

The use of fibre-reinforced polymer (FRP) sheets and laminates for strengthening concrete structures is established in both literature and practice as an effective method of retrofitting. Due to environmental concerns, there has been a growing interest in using natural FRPs as a more sustainable alternative to synthetic ones. In this study, a flax fibre-greenpoxy composite plate was designed and applied to upgrade both undamaged and pre-damaged reinforced concrete (RC) beams. The biocomposite plate was fabricated with 40% fibre content by mass using the hand lay-up technique. A four-point bending test was conducted on 1840 mm long steel-reinforced concrete beams. The pre-damaged beams were preloaded until the tension steel yielded to simulate service conditions before strengthening. The unstrengthened, undamaged and pre-damaged beams were tested to determine the effectiveness of the material as a retrofitting solution. The results show that the developed natural FRP plate enhanced the load-carrying capacity of the undamaged and pre-damaged beam sets by 43.35% and 65.02% respectively. Their application in the building industry can support the transition towards environmentally responsible construction practices.

In recent years, there has been growing interest in developing more sustainable building materials, including natural fibre-reinforced polymers/plastics (FRP). This study introduces a biocomposite plate made of flax fibre in a greenpoxy matrix, designed as a potentially more sustainable alternative to carbon and glass FRPs for retrofitting structures. Flax fibre was chosen for its high specific strength, and greenpoxy for its bio-based content. Alkali-treated flax fibres were used for enhanced mechanical and moisture absorption properties. Composite plate specimens for testing were fabricated using the hand layup technique. Tensile tests were conducted on samples with varying fibre contents to determine the optimal composition for strength and handling. Tensile and flexural tests were also performed on samples with the treated and untreated fibres to determine the efficacy of the treatment method in enhancing the material's mechanical performance. The alkali treatment enhanced the developed biocomposite's strength and moisture absorption properties. This study highlights the potential of flax-greenpoxy composite as a retrofitting solution to reduce the carbon footprint associated with the built environment.

This investigation provides a comparative examination of the mechanical and physical characteristics of cement paste and mortar incorporating banana fibers (BaF). The emphasis is placed on the influence of BaF on physical characteristics like density, total water absorption, and sorptivity, along with mechanical properties, encompassing ultrasonic pulse velocity, compressive strength, and flexural strength. Ten distinct mixtures, containing BaF contents varying from 0 to 2% by volume, were evaluated over a curing duration of 90 days. The findings indicate that incorporating BaF enhances the mechanical properties of cement paste and mortar, leading to improved strength and durability. Furthermore, a rise in water absorption was noted with the incorporation of fibers in both materials. The results emphasize the promise of BaF in improving the performance of cement-based materials, presenting a sustainable and economical alternative for construction uses.

Different components of a timber frame wall were analyzed: insulation, bracing panel, finishing panel and cladding. The performances of some commercial biobased flexible insulation (mix of fibres, cellulose, grass, recycled textile, sheepwool and flax) were compared to mineral glass wool and to an experimental mycelium panel. The bracing panels were made either of an ecological panel constituted of pressed vegetal fibers or a conventional OSB panel. The finishing panels consisted of a commercial clay board or a conventional gypsum board. The cladding consisted either of a new composite panel made from vegetal fibres, biosourced resin and lime; or a conventional spruce cladding.Several characterizations were conducted on insulation and on panels: water absorption, dimensional stability, vapor permeability, sorption-desorption tests, acoustic properties, airflow resistance, resistance to mold. Influence of temperature and humidity on thermal conductivity, and the impact of Florida aging or freeze-thaw cycles on the durability of thermal performances of insulating materials were also determined.Flexible biobased insulation materials exhibited similar performance as mineral glass wool (acoustics, dimensional stability, airflow resistance, etc.). A correlation between airflow resistance and acoustic performance was observed. The acoustic and hygroscopic performances of the clay board were relatively low and comparable to gypsum board. Under severe conditions (inoculation with fungal spores, 4 weeks, 29 ℃, RH ≥ 95%) commercial biobased insulation materials showed limited fungal growth (ranks 1a/5 to 2/5 according to EN ISO 846 and ranks 1/3 to 2/3 according to EN 15101). Mycelium was an exception and showed extreme sensitivity to fungal development (ranks 5/5 and 3/3). On the other side, most of finishing panels (conventional or biobased), showed higher sensibility (ranks 1c/5 to 5/5 according to EN ISO 846 and ranks 1/3 to 3/3 according to EN 15101). The finishing materials will not submit the same conditions of use (temperature, humidity) as the insulation materials and the finishing materials will be eventually associated with other elements (paint, render, coatings…). However these results are rather reassuring for contractors who might be worried about using biobased insulating materials. A correct setting up and normal use is necessary to prevent the risks of fungal development: protection of materials during the building phase, correct ventilation, no setting up of wet materials, replacement of insulation in case of accidental humidification, protection with water-vapor membranes, no capillary rise and compliance with the hygrothermal profile of the building wall in order to drive out the humidity. The thermal conductivity of flax and glass wool was almost unaffected (less than 5%) by either Florida tests (hot and humid) or freeze-thaw tests. This is a positive aspect for the durability of flax performance. It could be potentially similar for other biobased flexible insulating materials.This study refers to a second article were life cycle assessments were performed on the same materials. It showed that the insulation has a limited part of the total ecological impact of the wall. The outer and inner finishing panels and the fastening (screws or metal connectors) had also a significant impact. The vegetal bracing panel had a less impactful production process than conventional OSB, but its distant origin negated its environmental advantage. The study revealed that a clay finishing board can be more ecologically interesting than a conventional gypsum panel only in the case of the use of recycled jute fibers and a production site close to the building site. The greater thickness and higher density increased the impact of the transport.The present study highlights the importance of taking a holistic view of material properties for making informed choices.

The use of functionalized components in cement-based composites (CBC) is an innovative way to provide novel material’s capabilities. Carbon-based additions and fibers can modify electrical properties of CBC, such as piezoresistivity (PZR). PZR enables a new intrinsic capacity of CBC, relating the variation of material’s electrical resistance to material’s stress when subjected to external loads, successfully transforming CBC into a self-sensing material that can be used for Structural Health Monitoring (SHM).This study aims to evaluate the use of carbon fibers of biological sources (CF-BIO), obtained from lignin as raw material, which is a sustainable alternative to petroleum carbon fibers (CF-PAN), due to its natural origin and lower environmental impact. Fiber content required for achieving PZR capacity of CBC has been already defined for CF-PAN. The variation of electrical and piezoresistive properties as an effect of self-sensitive capacity were tested. These measurements were be used to calculate the fractional change resistivity (FCR) and the sensitivity rate of the material (Csens).

This study explores how bio-based materials catalyze innovation in the fields of organic and sustainable design while also making architecture more inclusive. By analyzing various international architectural projects, we highlight the ecological, structural, and aesthetic benefits of using materials such as modified wood, bamboo, biopolymers, and fiber-reinforced concrete. Bio-based materials offer an ecological alternative to traditional construction materials, and also pave the way for innovative architectural designs. This work underscores the need for close collaboration among architects, urban planners, engineers, and biologists to overcome challenges related to regulations, market acceptance, and the training of building professionals. Within a framework of combination between the two concepts of biophilic design and sustainable design, the bio-based materials also offer ecological benefits, such as the ability to self-renew or biodegrade naturally, reducing waste and promoting energy efficiency. The strategic use of bio-based materials can lead to architecture that meets sustainability and aesthetic standards, and is also profoundly social and inclusive, providing a healthier and more integrated living environment for everyone.

Lignin is a natural, aromatic polymeric material that accounts for about 25–30% of woody biomass. Recent research has shown the potential benefits of lignin in reducing the carbon footprint of the roading industry, and improvements in the performance of asphalt pavements. This work investigated the effect of a softwood (Pinus radiata) and a hardwood lignin (Eucalyptus globulus) on some key performance properties of bituminous binders. Rheological tests on the control bitumen and two lignin-modified bitumen blends at 20% concentration were conducted along with the particle sizing of the lignin materials themselves. Although the addition of lignins improved the rutting resistance of the blends, with hardwood being much more beneficial in this scenario, the crack resistance of the blends was compromised. The lignin-modified blends oxidised more than the control binder. Overall, the results of this study showed the addition of hardwood lignin was more beneficial than the softwood lignin. The interrelationship of different rheological parameters was investigated and the influence of ageing on the bituminous binders was discussed.

Brazil’s recent socioeconomic development has led to a steady increase in energy needs, primarily driven by the growing demand from the residential sector. While hydropower plays a substantial role in Brazil's energy mix, fossil fuel-based thermoelectric plants are often used to meet this rising demand. Although residential buildings represent a small fraction of the global carbon footprint, their long lifecycles and high energy consumption make them important contributors to global warming and climate change. Thus, in alignment with the Sustainable Development Goals (SDGs) and Brazil’s commitments under international agreements such as the Paris Agreement and the 2030 Agenda, it is essential to enhance research on comfortable, energy-efficient housing. This paper reviews recent literature to identify key aspects, the current situation, and future perspectives of low-carbon housing in Brazil. Various articles were analyzed from databases such as Scopus, ScienceDirect, Google Scholar, and the CAPES Journal Portal. Most research focuses on strategies for improving energy efficiency in housing design and construction, emphasizing thermal insulation, sustainable materials, natural ventilation, and renewable energy sources. Financial concerns present a significant challenge, as enhancing energy performance typically raises initial costs. Additionally, governmental, political, and regulatory issues are frequently cited as obstacles, highlighting the crucial role of public policies in promoting low-carbon housing. With advancements in technology and stronger public policies, low-carbon housing can play a vital role in mitigating climate change and facilitating the transition to a more sustainable society.

The Netherlands is facing a severe housing shortage. Newly build constructions are generally viewed as the go-to solution. Alternatively people can make more intensive use of existing constructions. Floor addition is viewed as a promising endeavor to increase the utilization of existing constructions. With their light weight characteristics biobased materials lend themselves very well for this purpose. This paper explores the economics of factory produced biobased floor addition.A literature study has been executed, as well as a Co-Creation sessions held with a construction team consisting of a project developer, a social housing agency and this paper’s author as an action researcher. In the session it has been explored how an integral approach could lead to cost reductions. During the sessions a budget review was held including various scenarios where the floor addition housing unit was approached as a biobased product instead of a traditional project.For many production processes a learning rate is observed, meaning that costs are reduced at a constant rate for each doubling of production. The general construction sector is not experiencing such a learning rate, however modular production in factories does seem to exhibit a building cost reduction potential of between 15% and 20%.While at the moment (2025) factory produced biobased floor additions seem to be more expensive than traditional building, they theoretically show the potential to bring overall construction costs down with anywhere between 15% and 39%. Amongst other reductions, product thinking can reduce financing costs and lower inflation adjustments, leading to this increased saving potential. More research, as well as actual projects are needed to verify the preliminary findings of this paper.

The growing demand for sustainable building materials is stimulating considerable research on bio-composites intended for the construction sector. Despite the technical challenges associated with their durability and fire resistance, bio-composites can provide environmentally friendly, load bearing components with useful mechanical properties. This paper provides an overview of the current research activities at TU Delft Department of Architectural Engineering and Technology in exploring five plant fibre reinforced polymer (PFRP) composites for various load-bearing applications. In addition to mechanical performance and durability, each bio-composite achieved one or more characteristic that improves the environmental sustainability of the bio-composite, namely: 100% bio-based; fabricated with simple low-tech equipment; sourced from bio-genic waste streams; assembled into a functional meta composite; formable into complex 3D shapes; and reformable at end of life. The findings presented in this paper provide useful insights of the material selection and manufacturing methods for each of the PFRPs and corresponding data from the performance testing. Moreover, the paper provides overarching observations across the five bio-composites and key recommendations for the future development of environmentally sustainable PFRP load-bearing components.

This paper examines contemporary architectural practices in Brazil and abroad that utilize full-culm bamboo as a primary structural element. Ten case studies - four in international contexts and six from the state of São Paulo - built from 2017 onward were systematically analyzed. The methodology comprised three main steps: (1) developing an analytical framework, (2) gathering data, and (3) conducting the analysis. The theoretical framework integrated approaches proposed by Mouton (2021), Widyowijatnoko (2012), and Larrinaga (2022), focusing on geometrical configuration, connector force transfer and fabrication techniques. Data for international examples were collected through documentary research, while Brazilian case studies were examined via site visits, interviews, and document analysis. Findings show that the structures exhibit geometric diversity, combining multiple connector types and fabrication methods. International projects frequently employ traditional “fish-mouth” connections that requiring specialized artisanal labor yet rely on relatively low-tech industrial components. In contrast, Brazilian examples feature more technologically advanced connectors, but use less overall bamboo volume, reflecting constraints related to labor availability and smaller building footprints. Additionally, although the International Network for Bamboo and Rattan (INBAR) identifies over 60 globally prioritized bamboo species, only a limited subset is selected for structural applications, dictated by local availability, supply-chain status, and existing knowledge of mechanical properties. By showcasing the interplay between design experimentation, construction methods, species selection and labor constraints, these insights pave the way for broader adoption of bamboo-based construction in global sustainability initiatives, particularly in the Global South.

The construction industry is one of the largest contributors to greenhouse gas emissions, particularly carbon dioxide (CO₂). The production of traditional materials such as steel and concrete requires significant energy input and releases substantial amounts of CO₂. With the urgent need to reduce emissions, the search for sustainable alternatives has intensified. Among these, wood-based biomaterials, such as cross-laminated timber (CLT), stand out for their carbon sequestration and storage capabilities. This study evaluates the feasibility of replacing conventional materials with biomaterials to reduce the embodied carbon emissions of single-family housing in Brazil. The methodology included a review of Environmental Product Declarations (EPDs) for replaceable materials, biomaterials, and non-replaceable materials, analyzing the CO₂-eq/kg emissions associated with their production. EPDs for nine materials were identified and assessed, with seven classified as “replaceable” and two as “replacements,” prioritizing national data whenever possible. A comparative analysis was conducted on a standard social housing project widely replicated across Brazil, quantifying its carbon emissions when constructed with conventional materials versus biomaterials, with and without considering the influence of biogenic carbon. This study contributes by highlighting the potential impacts of engineered wood in a highly utilized design in Brazil, supporting the decarbonization of the country’s residential sector.

The construction sector’s growing contribution to global emissions underscores the urgent need for a shift toward carbon neutrality. Foundation systems, often made from energy- and resource-intensive materials, are a significant source of embodied emissions in new buildings. Previous research by the authors indicates that foundation systems can account for up to 68% of the total embodied fossil emissions in carbon-negative buildings.This paper presents a catalog of buildings that have explored alternative foundation systems, utilizing minimally processed or recycled materials, with a focus on drastically reducing or eliminating concrete and steel. These case studies are grouped into three categories: stone and timber foundations, gabions, and natural cement/limecrete casting.A comparative Life Cycle Assessment (LCA) covering life stages A1–A3 is conducted. Key findings show that above-ground foundations, especially those incorporating timber, offer carbon-negative solutions, while gabion foundations can significantly reduce the environmental impact, even when used as below-grade solutions. The paper also examines the context behind these design choices, considering factors such as ground properties, seismic class, and building characteristics. The study demonstrates that low-carbon foundations for low-rise buildings are feasible when geological and geotechnical conditions are relatively favorable. Despite the specific limitations of the case studies, the analysis reveals key insights that lay the groundwork for future research.

Urban areas are increasingly experiencing the adverse effects of the “urban heat island” (UHI) phenomenon, driven by rapid urbanization, reduced green spaces, and the widespread use of heat-retaining materials. These factors exacerbate urban temperatures, increase energy demands, and contribute to environmental challenges. This paper explores recent advancements in mitigating UHI, focusing on bio-based solutions that offer a sustainable and innovative approach. Integrating bio-based materials, such as hempcrete, straw, and timber, into building construction and urban infrastructure can significantly reduce heat accumulation while enhancing thermal comfort and resilience to climate change. These materials not only lower urban temperatures but also contribute to reducing carbon emissions, improving energy efficiency in buildings, and fostering more sustainable urban environments. The study underscores the importance of bio-based materials as sustainable alternatives to conventional options, highlighting their potential for integration into urban planning to effectively address UHI, enhance energy performance, and support environmentally responsible urban development.

The use of steel bolted connections in multi-culm bamboo members reveals significant potential for sustainable construction applications. However, the low elastic stiffness of these members necessitates a thorough investigation of their behaviour to fully realize this potential in a design setting. Previous studies introduced an analytical method to characterize the elastic stiffness of bolted multi-culm bamboo axial members. The method effectively integrates the contributions of bamboo culms, steel bolts, washers, and gusset plates in determining the overall stiffness of the member. Despite these advancements, important geometric parameters of bamboo culms, such as their taper and straightness along their length, remain unaddressed. Therefore, this study addresses these gaps by examining a rational range of taper and straightness in bamboo culms and investigates the influence of these parameters on the elastic stiffness of bolted multi-culm bamboo members. The findings contribute to the design of bamboo structures, highlighting the effect of the unique geometric properties of bamboo culm on their stiffness parameter.

The development of bio-based materials marks a significant advancement in sustainable construction. However, concerns about the durability of these materials remain a key challenge. Water absorption is an indicator of durability in bio-based materials and warrants thorough investigation. In this context, this study aims at experimentally and numerically evaluating the phenomenon of water transport by capillarity action in partially saturated wood bio-concretes. The bio-concretes were produced with wood content of 40%, 45%, and 50% (used as bio-aggregates), and a cementitious matrix composed by cement, rice husk ash and fly ash. In addition to the capillary water absorption tests, the physical properties, including bulk density, open porosity, total water absorption, and drying shrinkage, were also evaluated. A non-linear finite-element-based model was employed to simulate the capillary transport phenomenon in bio-concretes by adopting a modified Darcy’s law. Based on the experimental results, the outcome of the inverse calibration allows to better understand the influence of the wood content on the Raleigh-Ritz pore size distribution and diffusivity behavior of the bio-concretes. The numerical results, which align closely with the experimental data, showed that bio-aggregates and their contents clearly modifies the diffusivity rule as a function of open porosity.

In the context of increasing use of geosourced materials such as hemp-clay to address the challenges of sustainable construction, accurately assessing their hygrothermal performance is essential. Hemp-clay walls, which combine insulating properties with natural humidity regulation, are often paired with interior and exterior plasters that significantly influence their overall behavior. A previous study conducted at the LGCGM laboratory using the WUFI software analyzed the hygrothermal performance of such systems under the assumption of a perfect contact between the plaster layers and the hemp-clay layer. However, this simplifying hypothesis does not always reflect the reality of material interfaces.In this study, we propose an advanced modeling approach using ANSYS software, which considers an imperfect contact between the plaster and hemp-clay layers, incorporating interface resistances and discontinuities. Thermal simulations were performed on walls comprising interior and exterior plasters, with material properties (thermal conductivity, density, heat capacity) calibrated through experimental measurements.The results reveal significant differences between the two approaches: WUFI underestimates temperature gradients at the interfaces, while ANSYS captures more realistic variations, especially under dynamic climatic conditions. These discrepancies directly affect the evaluation of thermal performance and the durability of hemp-clay walls.This study highlights the importance of accurately modeling material interfaces to optimize the performance of geosourced construction systems. It also contributes to validating more representative methodologies to support their integration into sustainable building practices.

In this paper, a hygrothermal model with capability of including hysteresis effect was developed in Python. Wind-driven rain (WDR) and solar radiation were incorporated to create dynamic climate conditions to mimic the climate loads in real situation. A hysteresis model from literature was integrated into the hygrothermal model. The model was validated against experimental data of a date palm concrete wall found in the literature. Incorporating hysteresis improved modeling accuracy of relative humidity (RH) values at three monitored depths, reducing the maximum error between simulation and measurement by 2.47% and lowering the mean absolute error (MAE) by 1.3%. Following validation, the hygrothermal performance of an eastward-oriented hempcrete wall was analyzed under Vancouver's future climate conditions. The results indicated that hysteresis has a minimal impact on the simulation outcomes of the hempcrete layer when rain penetration was excluded from the simulation. RH and moisture content (MC) showed the MAEs of less than 1% when comparing simulations with and without hysteresis. However, when rain penetration was included as a moisture source on the exterior surface of the hempcrete, MC discrepancies were increased between the models with and without hysteresis. The MAE for MC was 5.04%, with a maximum difference of 7.17%.

Geo-sourced materials represent a promising option, offering both thermal and environmental performance to reduce energy consumption and the use of non-renewable resources. In this context, a previous study, has worked on the development of fired clay bricks and characterized them from a multiphysical perspective. These materials exhibit moderate thermal conductivity and high moisture buffering capacity. To characterize their hygrothermal behavior at the wall scale, a test wall was constructed to simulate both indoor and outdoor climates. This paper investigates the hygrothermal behavior of a fired earth brick wall under typical summer climates in Morocco. The study consists of a numerical analysis conducted using WUFI Pro V6.8. The wall's hygrothermal response to these conditions is analyzed based on the temperature and relative humidity profiles at various positions in the wall, as well as the temperature and vapor pressure distributions. The results show that under a continental oceanic conditions, the wall's capacity to regulate heat and moisture is significantly influenced by its material properties. In particular, the moisture buffering capability of the fired earth bricks helps to stabilize indoor relative humidity levels, thereby reducing thermal and moisture fluxes. Additionally, the wall's response to daily climate cycles is characterized by active heat and moisture transfer within the outer layers of the wall, particularly through sorption-desorption processes.

In this work, we numerically investigate coupled heat and moisture transfer in a bio-based mortar wall containing micronized miscanthus fibers. The physical property inputs and their dependencies on temperature and moisture content were determined from literature data. A heat and moisture transfer model, based on the Künzel approach, was implemented in COMSOL Multiphysics. Simulations were compared with experimental data, demonstrating accurate estimations of temperature and relative humidity variations at different material depths. A maximum temperature deviation of 0.6 ℃ between experimental and numerical data was observed at a depth of 5 cm, while a maximum relative humidity deviation of 5% was obtained at a depth of 7.5 cm. Despite these discrepancies, the results are considered acceptable, given the inherent heterogeneity of bio-based materials and sensor accuracy. The developed numerical tool is adaptable, allowing the integration of additional physical models and phenomena to enhance the estimation of coupled heat and moisture transfer in complex bio-based building materials.

This study analyzes the mechanical behavior of concrete beams reinforced with PET fibers, using numerical modeling in ANSYS. Four configurations were studied: beam without fibers and without notch, beam without fibers and with notch, beam with fibers and without notch, and beam with fibers and with notch. The beams were subjected to three-point bending tests, considering loading and support conditions that simulate real forces. The analysis followed the recommendations of RILEM TC 162 (2003), and the fracture parameters were determined according to the RILEM TC 89-FMT (1990) standard. The calculations involved the critical stress intensity factor (KIC), which evaluates crack propagation resistance, and the critical crack tip opening displacement (CTOD), an indicator of ductility. The simulations showed that adding PET fibers improves fracture resistance and crack control. The results highlight the potential of PET fibers as sustainable reinforcement, contributing to structural durability and the reuse of recycled materials, aligning with environmentally responsible practices in civil construction.

Self-compacting concrete (SCC) plays a critical role in civil construction due to its ability to enhance productivity, improve on-site working conditions, and promote sustainability. Its distinguishing characteristic lies in the fresh-state properties, such as high flowability, controlled consistency, and resistance to segregation, which are essential for its overall performance. This study aimed to validate the behavior of a beam made with self-compacting microconcrete through numerical modeling using Ansys software. The Finite Element Method (FEM) was employed for numerical analysis to compare experimental results with the simulation outcomes. In the experimental phase, concrete mixture with 40% sand replacement by ornamental stone waste was evaluated. The microconcretes produced met the rheological criteria necessary for classification as self-compacting. Among the mixtures, the one incorporating 20% stone waste exhibited the best packing density, resulting in superior strength and durability. The numerical modeling, using three-dimensional finite elements, showed a convergence rate of 90% between the experimental values and the simulated results. This indicates a satisfactory validation of the experimental findings, with stress, deformation, and failure modes closely resembling those observed experimentally. The study demonstrates the effectiveness of this repair methodology for structural applications, confirming its potential for practical use in enhancing structural integrity.

This study explores, for the first time, the innovative application of machine learning (ML) techniques to predict the compressive strength of biobased concretes. To address these issues, a dataset was compiled from numerous previous studies, encompassing more than 200 different formulations of biobased concretes and 20 variables representing components properties and formulation details. A Decision Tree (DT) model was developed as part of the machine learning approach to analyze the dataset and predict the compressive strength of experimentally tested biobased concrete. This model operates by splitting the data into hierarchical decision nodes based on the most significant variables, creating relationships between input features and output predictions. To maintain computational simplicity, the Decision Tree model's maximum depth was restricted to 6. Results indicated that for the test set, the DT model achieved an R_Squared value of 0.72, a Mean Absolute Error (MAE) of 0.49 MPa, and a Mean Squared Error (MSE) of 0.52 MPa. While its performance still less accurate than more advanced models like the Artificial Neural Network (ANN), the Decision Tree model developed in this study provided valuable insights into the dataset's structure and the relative importance of different material properties; this was clearly demonstrated when testing the model on biobased concretes with a lower compressive strength. It is worthwhile noting that for compressive strength higher than 2 MPa, the DT proposed model unveiled lower performance, indicating the existence of overfitting. In sum, this research offers a fresh perspective by leveraging machine learning to address the complexities of biobased concrete, providing first step towards modeling the behavior of these complex materials using Artificial Intelligence technics.