Proceedings of the RILEM Spring Convention and Conference 2024
Volume 1
- 2025
- Book
- Editors
- Liberato Ferrara
- Giovanni Muciaccia
- Niki Trochoutsou
- Book Series
- RILEM Bookseries
- Publisher
- Springer Nature Switzerland
About this book
This book gathers peer-reviewed contributions presented at the RILEM Spring Convention and Conference, held in Milan, Italy on April 7-12, 2024. The theme of the Conference was “Advanced construction materials and processes for a carbon neutral society”, which was aimed at discussing advanced construction/eco-friendly materials and processes, for new and existing structures, towards a carbon neutral society. The volume covers the current and emerging approaches that lead to an optimized design and maintenance of constructions and systems. It includes the development of materials and structural service life models and life cycle design, in order to maximise longevity and level of service while minimising the environmental impact of constructions and systems. It also includes the analysis and design of larger systems, such as communities, cities or regions, aiming at reducing risk andincreasing resilience. The following subtopics are included: advanced materials and structural concept to enhance the resilience and robustness of the built environment and communities at local and global scales; risk based inspection and maintenance; life cycle analysis and service models; performance based design; improved design strategies by integrating materials and structures.
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Table of Contents
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Circular Economy
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Frontmatter
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Effects of Non-hazardous Construction and Demolition Waste on the Behaviour of Mortars
Annelise Cousture, Haruna Ibrahim, Elhem Ghorbel, George WardehThe chapter delves into the impact of substituting natural sand with non-hazardous construction and demolition waste (CDW) sands on mortar properties. It highlights the mechanical properties, porosity, and density of mortars with varying CDW substitution rates. The study finds that while flexural strength remains largely unaffected, compressive strength can be enhanced. However, the porosity and density of mortars are influenced by the intrinsic properties of CDW and their substitution rates. The interfacial transition zone (ITZ) observations reveal that the surface topography of CDW plays a crucial role in their integration into the mortar matrix. The findings offer valuable insights into optimizing the use of CDW in construction materials, contributing to sustainable waste management and resource conservation.AI Generated
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AbstractAccelerated urbanisation generates large quantities of construction and demolition waste (CDW). Most of this waste is inert and poses no environmental risk. In France, according to article R541–8, 72% of this waste is inert, and 26% is non-hazardous. Landfilling CDW involves ecological risks such as water and air pollution and a disastrous visual impact on the landscape. Concrete waste is the largest component of CDW, producing recycled gravel (RG) and recycled sand (RS). These recycled aggregates (RA) are natural aggregates (NA) coated with around 30 to 40% of old mortar. For many years, numerous researchers have studied the characteristics of concrete made with RA. However, RA generally contains non-hazardous waste (NHCDW) such as bricks, bitumen, earthenware, tiles, plastics, etc. There is a general lack of knowledge concerning the effects of NHCDW in RA. No more studies are available focusing on the impact of NHCDW on the behaviour and acceptability criteria of CDW materials used in activities such as backfilling, building, and landscaping. This study is part of the European project 101091679-MOBICCON-PRO (MOBile and Innovative Circularity for CONstruction PROducts)-HORIZON-CL4–2022-TWIN-TRANSITION-01). It aims to study the effect of these non-hazardous wastes on mortars’ physical and mechanical properties. The main objective is to establish threshold values for NHCDW (sand) to guarantee the required mortar properties. The experimental approach involves characterising NHCDW sands (density, porosity, water absorption) and designing mortars containing at least 30% of these sands with different proportions. The main properties studied are mechanical strength, porosity and density of the mortars. -
Valorization of Masonry CDW as Recycled Aggregate in Lightweight Structural Concrete
Zaharieva Roumiana, Petrov BoyanThe chapter delves into the potential of recycling masonry CDW as coarse aggregate in lightweight structural concrete, addressing the global demand for sustainable construction materials. It examines the advantages of using recycled brick aggregate (RBA) in terms of resource efficiency and reduced environmental impact. The study evaluates the physical and mechanical characteristics of RBA concrete, including compressive strength, flexural strength, and modulus of elasticity. It also investigates the bonding between RBA concrete and steel reinforcement, as well as durability aspects such as carbonation depth and shrinkage. The findings suggest that RBA concrete can be used to produce ordinary structural concrete with low RBA content, lightweight structural concrete with up to 60% RBA, and lightweight concrete with 100% RBA, each with its own set of advantages and challenges. The chapter concludes by highlighting the potential for increased recovery rates of masonry CDW and the need for additional measures to ensure the durability of steel reinforcement in lightweight concrete.AI Generated
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AbstractLightweight structural concrete offers an opportunity to decrease the dead load which is of great importance for improving both resource efficiency and earthquake behaviour of reinforced concrete and combined structures. Manufactured lightweight aggregate however are characterised by high embodied energy which reduces the environmental benefits of lightweight concrete. The aim of the current study was to evaluate the possibility for up-cycling of clay bricks construction and demolition waste (CDW) as aggregate in structural concrete. Three concrete compositions having different content of recycled bricks aggregate (RBA) were designed. The main characteristics of that concrete, required for the design of reinforced concrete structures, were determined. The bonding between RBA concrete and steel reinforcement bars was studied. Some durability (drying shrinkage and carbonation) were also investigated. It was concluded, that the valorization of masonry CDW as aggregate for concrete is possible and, depending on the RBA content, concrete for various purposes might be produced – an ordinary structural concrete when RBA share is of order of 20% of the total coarse aggregate and a lightweight concrete, having reduced dead load and satisfactory compressive strength and bonding with rebars when the replacement rate varies from 60% to 100%. Other aspects of the RBA lightweight concrete such as modulus of elasticity, shrinkage and carbonation depth showed lower performances. Therefore, RBA containing concrete requires adjustments in the mix design and in the behaviour prediction models, as well as measures to ensure the durability, similar to those for concrete with other type of lightweight aggregate. -
The Impact of Carbonated Fine Recycled Aggregates on Sulfate and Acid Attack of Mortar
Chao Qun Lye, Sze Dai PangThe chapter delves into the impact of carbonated fine recycled aggregates (FRCA) on the durability of mortar, specifically focusing on resistance to sulfate and acid attacks. It begins by introducing the growing trend of sustainable practices in the construction industry, with a particular emphasis on carbon mineralization as a method for recycling concrete waste. The study investigates the potential of FRCA as a replacement for natural sand in mortar, evaluating its effects on mechanical properties and long-term durability. Through extensive experimental procedures, including sulfate and acid resistance tests, the chapter uncovers that while FRCA can improve initial material characteristics, it may reduce resistance to sulfate and acid attacks. Notably, the addition of ground granulated blast furnace slag (GGBS) or a reduction in the water/cement ratio can mitigate these negative effects. The chapter also highlights the formation of gypsum in sulfate-exposed FRCA mortar and the significant mass loss in acid-exposed samples. These findings are crucial for ensuring the long-term performance and durability of sustainable construction materials, making the chapter a valuable resource for professionals seeking to optimize the use of recycled aggregates in concrete production.AI Generated
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AbstractThe construction industry's quest for sustainability has heightened interest in alternative construction materials, particularly the adoption of fine recycled concrete aggregates (FRCA) as a viable substitute for natural sand in concrete and mortar. The carbonation of FRCA, attributed to the adhered cement paste, has demonstrated the ability to enhance the properties of fine RCA, thereby broadening its applications. This study delves into an underexplored research area concerning carbonated FRCA, specifically examining their influence on the long-term sulfate and acid resistance of mortar. This inquiry stems from concerns about potential thaumasite sulfate attack, which could arise due to the presence of carbonates resulting from the carbonation process of fine RCA, coupled with moisture exposure. In this investigation, carbonated FRCA serves as a complete replacement for natural sand in mortar mixes, subjected to magnesium sulfate solution and hydrochloric acid. Furthermore, the study evaluates the sulfate resistance of carbonated FRCA mortar with a reduced water/cement ratio and explores the inclusion of ground granulated blastfurnace slag (GGBS) as a partial replacement for Portland cement. Additionally, XRD analysis of samples extracted from deteriorated specimen surfaces provides insights into their mineralogical compositions. This research offers a good understanding of long-term performance implications. By contributing to discussions on sustainable construction practices, it underscores the necessity for further exploration in this promising field. -
Valorization of Delithiated β−Spodumene as a Raw Construction Material
Ali Karrech, Elhem GhorbelThis chapter delves into the valorization of delithiated β-spodumene (DβS) as a raw construction material, addressing the growing need for lithium due to the increasing demand for smart devices and clean vehicles. It examines the properties of DβS, a waste material from lithium-ion battery production, and its potential as a precursor for geopolymers. The study compares the performance of geopolymers made with DβS and ground granulated blast-furnace slag (GGBS), with and without sodium silicate, and evaluates their compressive strength over time. The findings highlight the feasibility of incorporating both solid and fluid waste streams into a single product, offering a sustainable solution for the construction and waste management industries.AI Generated
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AbstractWith the ecological transition and the move towards net zero emission, lithium is the subject of much attention. Lithium is a key element in the manufacturing of batteries for electrical vehicles, which are expected to dominate the market in the European Union from 2035 onwards.Lithium occurs in more than 100 minerals including spodumene, petalite, or lepidolite. In Australia, spodumene is the main source of hard rock lithium. Australia is the world leader in lithium production, with five mines representing almost half of the world’s total lithium production in 2022. It is ranked second in the world in terms of proven reserves, with 6.2 million tonnes.Spodumene contains about 6% Li2O when it is pure. In order to extract lithium, α-spodumene must undergo a phase transformation that is activated by heat. Therefore, the spodumene processing results in several waste components both in the solid and liquid streams. The solid residue may contain aluminosilicates that are intrinsic to the spodumene crystal and other components that are due to the process itself including sodium sulphate (obtained upon sulphating β-spodumene) and various hydroxides that result from the acid neutralisation. Overall, significant quantities of residues can be formed that can become an environmental burden if not reused in a circular economy.The objective of this research is to elaborate geopolymer mortars with different proportions of β-spodumene as alkali-activated materials and slag. It has been established that an optimum binder is obtained with 25% β-spodumene and 75% slag. -
Potential Use of Carbide Lime Waste in Construction: A Comprehensive Analysis
Teodora Ilić, Kerstin Elert, Encarnación Ruiz-Agudo, Carlos Rodriguez-NavarroThe chapter delves into the potential of carbide lime waste, a by-product of acetylene gas production, for use in construction materials. It discusses the environmental and economic advantages of integrating industrial alkaline residues into construction, focusing on the unique properties of carbide lime. The research presents a thorough analysis of carbide lime pastes and powders, comparing them with conventional calcitic hydrated limes prevalent in industrial and construction applications. The study employs advanced techniques such as X-ray diffraction, transmission electron microscopy, and mercury intrusion porosimetry to understand carbide lime's properties and its potential applications in sustainable construction. The chapter also highlights innovative treatment approaches to purify carbide lime, ensuring its suitability for construction applications while preserving its capacity for CO2 capture and air-setting.AI Generated
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AbstractThe growing interest in repurposing industrial alkaline wastes for construction has driven research toward sustainable practices, aiming to address environmental concerns and circular economy principles. This study focuses on the utilization of carbide lime waste, a by-product of acetylene gas production, in construction materials. The current large amounts of calcium carbide produced worldwide, leading to carbide lime waste, underscore the urgency of finding alternative uses for this material. Carbide lime waste is typically discarded in ponds, a disposal method that poses significant environmental threats. Recycling carbide lime in construction not only addresses waste management issues but also offers a sustainable solution for capturing greenhouse gases via its carbonation. Here we present a comprehensive analysis of carbide lime properties, comparing them with traditional calcitic limes. For this task, we used X-ray diffraction, porosimetry, thermogravimetric analysis, and electron microscopy. Carbide lime, primarily composed of calcium hydroxide, demonstrates unique features, including micro and nanoscale portlandite particles, and compatibility with various building constituents. Our study highlights the challenge posed by impurities in waste carbide lime (i.e., sulfides and heavy metals) and underscores the need for optimal process control. Notably, we unveil the remarkable carbonation dynamics and kinetics of carbide lime, which outperforms traditional calcitic limes. Key developments and findings include the purification and optimization of carbide limes, morphological distinctions in carbonated lime crystals, pore characteristics, and (enhanced) reactivity, as compared with industrial hydrated lime. -
Austrian Mineral Waste Streams for Alkali-Activation: A Comprehensive Suitability Evaluation Approach
Amr Hassan, Stefanie Radinger, Ognjen Rudic, Bettina Ratz, Florian Steindl, Florian Mittermayr, Iris Zögl, Sara Raic, Martin Dietzel, Cyrill GrenggThe chapter introduces a multi-stage approach for evaluating the reactivity of Austrian mineral waste streams for alkali-activation in concrete. It discusses the materials and methods used, including the characterization of various waste streams and the development of alkali-activated material (AAM) binder systems. The study highlights the potential of these waste streams to reduce landfilled waste, CO2 emissions, energy consumption, and raw material consumption associated with cement production. The chapter also presents the mix design and characterization methods used to assess the performance of the AAM binders, including compression testing and leaching tests for environmentally hazardous species. The findings of this study contribute to the development of sustainable and environmentally-friendly concrete binders.AI Generated
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AbstractAlkali activated materials (AAMs) are an interesting class of alternative construction materials with potentially low environmental impact and physicochemical properties fulfilling the requirements for a wide range of engineering applications. One reason therefore is their ability to utilize mineral wastes and industrial by-products as raw materials to produce clinker-free binders. To date the research is mostly focused on fly-ash, GGBS and metakaolin-based AAMs, whereas the utilization of other probable viable wastes and by-products for AAM production (e.g. metallurgic slags, mineral wools, and construction and demolition waste) are often overlooked. Such wastes and by-products are produced in substantial amounts and frequently deposited in landfills, posing a notable environmental burden. In this work, the systematic evaluation of various Austrian mineral wastes and by-products to be utilized as AAM precursors is presented. First, the physical, chemical and, mineralogical characteristics of wastes were assessed. Thereafter, their potential reactivity as binder components was systematically investigated in AAM paste mixes series. The developed binder systems were investigated by characterizing fresh and hardened pastes through visual observations, spread flow, and compressive strength. Moreover, a fundamental understanding of the environmental material characteristics was attained by leaching tests. This strategy enabled a preliminary reactivity evaluation of different mineral wastes and the development of binder systems, exhibiting high waste content, suitable fresh properties and high strength development, for further tuning and optimization. -
Thermally Treated Residues and By-Products as Components of Waste-Based Alkali-Activated Materials
Florian R. Steindl, Stefanie Radinger, Amr Hassan, Ognjen Rudic, Katharina Weisser, Anna Krammer, Klaus Doschek-Held, Bettina Ratz, Iris Zögl, Sara Raič, Florian Mittermayr, Cyrill Vallazza-GrenggThe chapter delves into the potential of thermally treated mineral wastes and by-products as components in waste-based alkali-activated materials. It highlights the pressing need for resource efficiency and reduced CO2 emissions in the building materials sector. The study presents a high-temperature carbothermal treatment process that transforms these wastes into a highly reactive GBFS-like slag fraction. This fraction is then analyzed for its reactivity in cementitious systems and suitability as an alkali-activated binder component. The results show that upcycled slags exhibit significant hydraulic reactivity and enhance the strength development of alkali-activated pastes and mortars. The study concludes by emphasizing the importance of regulatory revisions to enable large-scale usage of these innovative, sustainable binder components, paving the way for a circular building materials economy.AI Generated
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AbstractDespite dwindling supplies of traditional SCMs like granulated blast-furnace slag (GBFS), a plethora of industrial mineral residues and by-products are currently not utilised in ordinary Portland cement (OPC) or alkali-activated material (AAM) binder systems. In many cases, this is due to unfavourable properties of these materials, such as low reactivity or high contents of harmful substances. This contribution demonstrates how various residues and by-products can be utilised as binder components by a thermal treatment at temperatures >1400 ℃ followed by wet granulation. Through chemical and mineralogical characterisation, it could be shown that resulting materials (“up-slags”) are similar to GBFS, consisting mainly of CaO, SiO2, Al2O3 and MgO with high amorphous contents. Subsequent R3 and activity index tests and fabrication of AAM mortar and paste with a combination of up-slag and non-treated material proved the reactivity of the up-slags in OPC and AAM systems, respectively. The results demonstrate that mineral residues can be valorised as reactive binder components through thermal treatment, supporting a pathway towards a climate-friendly, energy-efficient circular building materials economy while mitigating shortages of traditional SCMs. Through carbothermal reduction, potentially valuable metals (e.g. Fe, Mn, Cr) can be reclaimed during the upcycling process. Further research has also been identified as necessary to improve our understanding of chemical and mineralogical boundary conditions for using upcycled slags as AAM binder components. -
Effect of Increasing Slag Content on the Workability and Mechanical Properties of CDW-GGBS Based Geopolymer Composites
Jasper Vitse, Dongsheng Zhang, Jiabin LiThis chapter delves into the critical issue of construction and demolition waste (CDW) and its environmental impact, highlighting the potential of geopolymers as a sustainable alternative to conventional building materials. The study focuses on the optimization of geopolymer composites using ground granulated blast furnace slag (GGBS) and CDW, investigating the effect of varying GGBS/CDW ratios on the fresh and hardened properties of these composites. The research demonstrates that increasing the slag content initially reduces setting time and enhances compressive strength, but further increases can lead to delayed setting times and reduced flowability. The optimal GGBS/CDW ratio of 70/30 is identified, yielding significant improvements in strength while maintaining adequate workability. This work contributes to the development of eco-friendly construction materials with enhanced performance, addressing the urgent need for sustainable waste management in the construction industry.AI Generated
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AbstractThe construction industry has a significant effect on the sustainability calendar, in terms of greenhouse gas (GHG) emissions, consumption of natural resource, and waste generation. The manufacture of ordinary Portland cement (OPC) is responsible for around 7% of the global CO2 emissions. Geopolymers are often considered as a potential eco-friendly alternative to OPC because of reduced environmental impact. In recent years, research on the use of construction and demolition waste (CDW) precursors to manufacture geopolymers has attracted worldwide interests owing to several significant advantages. It was found that, however, the reactivity of CDW precursors is generally low and the synthesized geopolymers exhibit low strength in most cases, except special curing regime is employed. Adding ground granulated blast furnace slag (GGBS) benefits to improve the performance of CDW-GGBS-based geopolymers. However, the influence of increasing GGBS/CDW ratio on the properties of geopolymers after ambient curing is not yet well understood. In this study, sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) are used as alkaline solutions, and the effect of raising GGBS/CDW ratio from 50/50 towards 80/20 is investigated on setting time, flowability index and compressive strength of the geopolymer composite (with Na2O/b = 8%, SiO2/Na2O = 1.33 and w/b = 0.35). The test results indicate that an increase in GGBS content has a beneficial effect on compressive strength increase and reduction in setting time until a GGBS/CDW ratio of 70/30. The test data helps to gain a better understanding of the fresh and hardened properties of CDW-GGBS-based geopolymers after ambient curing. -
Study on the Fracture Performance of Carbon Fiber Reinforced Recycled Powder-Based Geopolymer Composites
Dongsheng Zhang, Jasper Vitse, Veerle Vandeginste, Qiuning Yang, Jiabin LiThis chapter delves into the fracture performance of carbon fiber reinforced recycled powder-based geopolymer composites, a sustainable alternative in construction materials. The study investigates the effects of carbon fiber length and dosage on the material's strength, toughness, and crack resistance. Through a series of three-point bending notched beam tests, the research reveals that a 0.9% carbon fiber dosage significantly enhances the material's peak load, fracture toughness, and critical effective crack length. The findings suggest that optimizing carbon fiber content can lead to the production of high-toughness geopolymer materials, contributing to more durable and reliable construction projects.AI Generated
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AbstractTo overcome the common shortcomings such as high brittleness, low toughness, and susceptibility to cracking in geopolymers, a three-point bending fracture test was conducted to study the effects of carbon fiber (CF) length (6 and 12 mm) and different contents (0.3, 0.6, 0.9, 1.2, and 1.5%) on the fracture performance of a recycled powder-based geopolymer (RPG). Parameters such as Load-CMOD curve, peak load, initial fracture toughness, unstable fracture toughness, and critical effective crack were used as evaluation indicators. The results show that the addition of CF within a certain dosage range can improve the fracture performance of RPG; After adding CF to geopolymer, the peak load, initial fracture toughness, unstable fracture toughness, and critical effective crack of the specimen can be significantly increased. These fracture parameters show a trend of first increasing and then decreasing as the CF content gradually increases, reaching their maximum value at a CF volume fraction of 0.9%. At this point, the load–crack opening displacement curve of the specimen was the highest, and the envelope area between the coordinate axes was the largest. Compared with the 12 mm fibre, the 6 mm CF has a stronger enhancement effect on the fracture toughness of the geopolymer. -
On the Prediction of Strength and Optimum Mix-Designs of Mineral-Waste-Based Alkali-Activated Materials
Iris Zoegl, Ognjen Rudić, Bettina Ratz, Amr Hassan, Stefanie Radinger, Florian Steindl, Cyrill Valazza-Grengg, Martin Dietzel, Sara RaičThe chapter delves into the use of alkali-activated materials (AAMs) as a sustainable alternative to Ordinary Portland Cement (OPC), highlighting their potential for reduced environmental impact. It introduces the Design of Experiments (DOE) and Response Surface Methodology (RSM) as tools for understanding and optimizing the mechanical properties of AAMs. The study focuses on a mineral waste-metakaolin-based binder system, investigating the influence of waste content on strength-related properties and optimizing mix proportions for maximum strength. The use of statistical methods such as ANOVA and desirability functions allows for a thorough analysis and optimization of the binder system, providing valuable insights into the development of eco-friendly building materials.AI Generated
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AbstractReducing the carbon footprint of building material production (~9% of anthropogenic CO2) in the short term is essential to achieve global climate targets. In this regard, certain mineral wastes and secondary raw-materials show large potential as low-CO2 alternatives to be utilized in alkali-activated materials (AAMs). In order to establish mineral-waste-based AAMs as strong future competitors in the construction industry, functional binder systems have to be developed to meet material requirements. Tapping into these unexploited waste streams and exploring their potential as binder components is based on their respective mineralogical and chemical compositions, which determine the desired material properties of the mix-design (expressed e.g. in elemental ratios such as Si/Al). By generating waste-stream-related patterns and variable associations in the context of bulk chemistry and mineralogy of available waste types, factors for the binder development stage are elaborated. During this step, optimum experimental conditions can be achieved by statistical methods such as the design of experiments (DOE) and response surface methodology (RSM), including desirability function-based methods. Such approaches yield time- and/or cost-efficient strategies by optimising the amount of available resources used. For preliminary results the following interactive variables were considered: (i) waste content, (ii) compressive strength and (iii) water/binder ratio. Future focus is given on the evaluation of more complex systems containing a variety waste sources. -
Suitability of Soil and Tunnel Excavations as SCM - Comparison of Thermal and Mechano-Chemical Activation
Lea Ruckes, Matthias MaierThe chapter delves into the suitability of soil and tunnel excavations as supplementary cementitious materials (SCM) through thermal and mechanochemical activation. It discusses the challenges of using kaolinitic clays and the potential of 2:1 and 2:1:1 clay minerals from secondary raw materials. The study investigates the pozzolanic reactivity of three different secondary raw materials, comparing the effectiveness of mechanochemical activation (MCA) and thermal activation (TA) in enhancing reactivity. The authors explore the microstructural changes induced by MCA and TA, highlighting the unique characteristics of MCA in reducing particle size and altering particle morphology. The chapter also examines the particle size distribution and pozzolanic reactivity of the activated materials, providing insights into the potential of secondary raw materials as sustainable SCM in the cement industry.AI Generated
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AbstractConstruction and demolition waste represents one of the largest waste streams in the European Union. The soil and stone fraction accounts for the biggest share of these materials. This fraction includes waste materials from tunnelling and excavations, which often contain significant amounts of clay minerals. The demand for raw materials containing clays will increase significantly due to the growing interest for calcined clay as emerging SCM. As the extraction of primary raw materials is to be reduced on the way to a circular economy, secondary materials containing clay must be tapped and new processing methods developed. In this study, different samples from drill cores of planned tunnelling operations and soil excavations were characterized with focus on their mineralogical composition. All investigated materials show a high carbonate and a low to moderate clay content, dominated by 2:1 and 2:1:1 clay minerals. The samples were activated by thermal and mechanochemical activation and the alteration of the physical and mineralogical properties was analysed. The effects of mechanochemical activation on particle characteristics and crystal structures known from studies of pure clays could be confirmed. Mechanochemical activation was proven to significantly enhance the pozzolanic reactivity of a material with a clay content of 40 wt. %, while it showed no benefit regarding the activation of materials with clay contents of 20 wt. % or below. The study demonstrated that mechanochemical activation can have great potential as an alternative activation method for secondary clays, while the scale-up and associated energy demand still need to be proved. -
Microstructure Evolution of Cementitious Matrices Utilising Graphite Mine Tailing as Supplementary Cementitious Materials
Surya Maruthupandian, Andreas Chrysanthou, Antonios KanellopoulosThe chapter delves into the utilization of graphite mine tailings as supplementary cementitious materials, emphasizing the microstructural evolution of cementitious matrices over time. It begins with an introduction to the environmental and economic concerns surrounding the cement industry and the potential of mineral wastes as sustainable alternatives. The experimental methodology outlines the preparation and thermal activation of mine tailings, followed by the characterization of their chemical composition and mineralogy. The study then focuses on the fresh properties and heat of hydration of cementitious pastes containing mine tailings, revealing a reduction in reactivity and heat of hydration with increased replacement of ordinary Portland cement. The microstructural analysis, conducted using scanning electron microscopy, highlights the presence of ettringite, C-S-H, and portlandite, with the matrix becoming more compact over time. Unhydrated mine tailings are observed in the cement paste samples, indicating delayed nucleation and secondary hydration. The chapter concludes by underscoring the viability of incorporating mineral waste into modern cement formulations, contributing to sustainable construction practices.AI Generated
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AbstractThe tailing used in this study, is a by-product of graphite mining and is generated from the floatation process of the finer ore concentrate. It is predominantly silicate and was provided in dry state which comprised a few lumps up to a size of 20 cm. The mineralogy of the mine tailing was studied, based on which, a treatment process of calcination at 850 ℃ for 2 h was adopted.This study examines the microstructure of hydrated cementitious pastes with 10%, 20%, and 40% treated mine tailing as ordinary Portland cement (OPC) replacement and with w/c ratios of 0.3, 0.4, and 0.5. Microstructure was examined after 7, 14, 28, 56, and 90 days of curing. Calcium hydroxide (C-H), calcium silicate hydrate (C-S-H), ettringite, biotite, and quartz were found in cementitious paste with mine tailing samples. Though the hydration products C-H, ettringite, and C-S-H were present in both OPC and OPC-mine tailing mixes, the C-S-H morphology in OPC-mine tailing mixes was different. Higher silica content in mine tailing created a constrained space, resulting in formation of a crumpled foil C-S-H. In OPC-mine tailings samples, C-H nucleation was also observed in later ages such as 56 days indicating secondary hydration. This also results in more compact matrices at the later ages. These findings together with the findings of FTIR and XRD studies give an insight into the hydration of cementitious pastes containing mine tailing. -
Reuse of EAF Slag as Aggregates in Structural Concretes
Alan Piemonti, Antonio Conforti, Giovanni PlizzariThe chapter 'Reuse of EAF Slag as Aggregates in Structural Concretes' delves into the potential of Electric Arc Furnace slag as a sustainable replacement for natural aggregates in concrete production. It begins with an introduction to the significant quantities of EAF slag generated annually and the environmental benefits of its reuse. The materials and mix design sections detail the composition of the concrete mixtures, including the use of EAF slag as a partial replacement for natural aggregates. The results and discussion sections present the characterization of the concrete mixtures, highlighting improvements in compressive strength, elastic modulus, and ductility. The chapter also includes an in-depth analysis of the flexural and shear behavior of concrete beams made with EAF slag, demonstrating their comparable performance to traditional concrete beams. The experimental results and comparisons with Eurocode 2 calculations provide valuable insights for civil and structural engineers interested in sustainable concrete design.AI Generated
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AbstractThe growing interest of the international community in a more circular economy has led to the introduction of materials from industrial production and/or recovery in the construction sector, formerly classified as waste for disposal but now considered of fundamental importance for environmental protection and for reducing the exploitation of natural resources. Several studies available in the literature have shown how slags from the production of steel in electric arc furnaces (EAF slags), if properly treated, can be reused for concrete production. Italian steel mills are almost all equipped with electric arc furnaces from which, in addition to the primary material, an estimated 2.1 to 3.1 million tonnes per year of EAF slags can be generated. Unfortunately, about 15–20% of these slags are still destined for landfill disposal. Given the advantages and disadvantages that EAF slags provide to the mix and the possibility of the Italian concrete market to incorporate the entire quantity of slags produced at national level, even with limited replacement percentages, the present work aims to provide a contribution on the study of concrete made with electric arc furnace slags (EAF). Three concrete mixtures have been produced and in two of which the natural fine and coarse aggregates has been replaced by two different percentage of EAF slag, 25 and 50%. Once the mechanical characterisation of the mixtures had been carried out, they were then used to produce full-scale beams in order to study both flexural and shear behaviour. -
Understanding the Effects of Wood Biomass Ash on Brick Quality
Ivana Banjad Pečur, Matija Vujec, Ivana Carević, Ivan Koloda, Anđelina Bubalo, Dražen Vouk, Nina ŠtirmerThe chapter delves into the historical significance of bricks and the evolution of brick construction. It examines the potential of integrating wood biomass ash (WBA) into brick production as a sustainable alternative, addressing the environmental challenges posed by WBA accumulation. The study evaluates the impact of WBA on brick properties, including dimensional stability, water resistance, and mechanical strength. It also highlights the importance of sample preparation and the need for collaboration with brick manufacturers to ensure the practical applicability of laboratory results. The chapter concludes by emphasizing the significant impact of WBA on brick properties and the necessity for further research to optimize its use in brick manufacturing.AI Generated
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AbstractThe aim of this study is to determine the impact of wood biomass ash (WBA) as a substitute for part of the clay on the properties of bricks and to validate laboratory tests in collaboration with brick manufacturers to ensure consistent product quality at industrial production level. Six samples of WBA from different locations in the Republic of Croatia were taken for testing purposes. This work examines the properties of bricks in which WBA partially replaces clay, employing the hand moulding method for brick preparation. Bricks are shaped into both disc and prism forms, allowing us to assess the impact of WBA on various properties such as shrinkage during drying and firing, compressive strength, and water resistance properties, including water absorption by boiling, absorption, and saturation coefficient. The results indicate that even a minimal substitution of only 3% of the clay with WBA significantly influences the water resistance and shrinkage properties. The sample preparation process significantly influences the properties of the bricks, which underlines the need to clearly outline how the samples were fabricated. -
Excavated Earth Incorporating Hemp and Tannin for the Manufacture of Thermally Insulating Mortars for Wall Panels
Elhem Ghorbel, Filippo Cuccagna, Valerie Mignot, Mohammed NoualiThe chapter delves into the ambitious Grand Paris Express project, highlighting the massive excavation of earth and the potential environmental risks. It explores the value of surface earthwork-excavated material in construction engineering, specifically for earth-based mortars and thermal insulation. The study investigates the effects of incorporating hemp fibers and tannin into mortars made from tunnel earth, aiming to create standard-compliant materials for partition walls or interior coatings. The research compares these mortars with raw earth-based ones, analyzing both fresh and hardened properties. The use of tannin not only colors the material but also enhances its mechanical and physical properties, making it a promising solution for sustainable construction practices.AI Generated
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AbstractThis work aims to investigate the possibility of reusing tunnel excavated material to produce an earth-based mortar. The elaborated earthen mortars will be used as interior partition walls or coating to replace plaster materials. The challenge of this technic is multiple, in the context of a strategy to achieve a neutral carbon footprint in building: (1) to avoid the use of gypsum-based materials which, during demolition, can pollute the waste destined for re-use; (2) to reduce as far as possible the need to landfill excavated earth; (3) to develop panels or coating materials with improved thermal efficiency and environmental impact.The mechanical, thermal and hydric properties of excavated earth mortars were characterized after 28 days. A previous study pointed out that the increase of cement content improves the mechanical characteristics but at the same time affects negatively the thermal properties as well as the environmental factor. Hence, all mortars developed were stabilized with cement at 5% by mass. In total, 9 formulations were developed by varying the amount of hemp fibres and tannin powder. It is established that the addition of 1% tannin and 1.2% hemp fibres provided the best solution for optimum mechanical, thermal and hydric properties.This study not only facilitates the development of a material with favourable thermal properties and other suitable usage characteristics but also addresses a crucial issue concerning the management of excavated materials from major infrastructure projects. By proposing a solution aligned with the principles of the circular economy and sustainable development, it offers a practical approach to handling excavated materials in an environmentally responsible manner. -
Comparative Effects of Polyethylene and Polypropylene-Based Waste Fishing Gear Fibers on Mechanical Parameters and Porosity of Cementitious Materials
Ali Hussan, Nassim Sebaibi, Badreddine El Haddaji, Mohammed ZelloufiThe chapter delves into the comparative effects of polyethylene and polypropylene fibers derived from waste fishing gear on the mechanical properties and porosity of cementitious materials. It begins by discussing the general information and significance of fiber reinforcement in concrete, highlighting the environmental benefits of repurposing waste fishing gear. The study focuses on the physical and mechanical characterization of waste fishing trawl (WFT) and waste fishing rope (WFR) fibers, and their incorporation into cementitious materials. The results show that both types of fibers enhance flexural and tensile strength, though at the cost of reduced workability and increased porosity. The chapter concludes by emphasizing the potential of WFT and WFR fibers in improving the mechanical characteristics of cementitious materials, while also noting the increase in porosity. This research offers valuable insights into the sustainable use of waste materials in construction, contributing to both environmental conservation and structural performance.AI Generated
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AbstractThe current global trend towards sustainability has generated a fresh enthusiasm for the conversion of waste materials into useful resources across all industries. Within the construction industry, conventional cement-based materials have played a crucial role in the advancement of infrastructure. However, there is a growing recognition of the pressing requirement for more environmentally sustainable alternatives. Within this particular framework, the reclamation and repurposing of Waste Fishing Trawl (WFT) fibers made from polyethylene and Waste Fishing Rope (WFR) fibers made from polypropylene emerge as a noteworthy strategy that combines environmental awareness with innovative manufacturing techniques.This study investigates the impact of polyethylene-based WFT fibers and polypropylene-based WFR fibers on the mechanical characteristics of Cementitious Composites (CC). The study sheds light on the difference in the effects of the two types of fibers on the mechanical properties of the CC. Significantly, the incorporation of these fibers elicits discernible alterations in the mechanical characteristics. The mechanical properties, particularly flexural and tensile strength, demonstrate a notable enhancement, but the compressive strength remains nearly unchanged. Additionally, an intriguing fact emerges about the porosity of the cement-based material. The present work provides evidence of an observed increase in porosity as a consequence of the inclusion of WFT and WFR fibers. When discussing the fresh state properties, the incorporation of both types of fibers led to a reduction in the workability of the cementitious matrix. -
Gypsum as a Bloating Agent for Expanded Concrete Waste Fines LWA
Smadar Kedem Elmachily, Semion ZhutovskyThis chapter delves into the recycling of concrete waste fines (CWF) into self-expanding lightweight aggregates (LWAs) using gypsum as a bloating agent. It examines the impact of chemical composition and sintering temperatures on the bloating efficiency of LWAs, highlighting the importance of understanding the bloating process to achieve optimal physical properties. The study involves the analysis of CWF material using ICP-OES and XRD techniques to determine its chemical and mineral composition. The results show that high-calcium samples form liquid phases with lower viscosities and emit more gaseous phases during sintering, contributing to the formation of larger pores in the LWAs. This research offers a viable alternative to landfill disposal, promoting the sustainable use of concrete waste fines in the construction industry.AI Generated
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AbstractConcrete waste fines (CWF) are a major by-product of concrete recycling. Recycled coarse aggregates have already been introduced into the construction industry. However, little has been done on the utilization of the fine fraction of concrete waste. This research investigated a method of recycling CWF to produce expanded lightweight aggregate (LWA) using gypsum as a foaming agent. Further, the effects of quartz and bauxite addition on the bloating characteristics of LWA were studied by utilizing the CWF by different ratios of 25, 36, 72, and 100%. This was done to modify the chemical composition of the mixture in accordance with Riley’s ternary diagram. A physical and chemical analysis of the raw materials was conducted initially using X-ray diffraction, and inductively coupled plasma spectroscopy. A series of tests were conducted with the burning temperatures and gypsum content as experimental variables. A detailed analysis of the apparent density, water absorption, and bloating index was conducted and the microstructure of LWA particles and pore sizes were studied using optical fluorescence microscopy. The experimental results demonstrated that adding 15% of gypsum by weight to the 25% CWF mixture and a maximum heating temperature of 1200 ℃, resulted in a bloating index of 155%, an apparent density of 573 kg/m3, and a water absorption of 128 wt. %. This expansion of LWA was achieved primarily due to the gypsum acting as a bloating agent. The research confirmed the feasibility of producing high-quality LWAs by combining fine concrete waste with gypsum. -
Exploring Sustainable Alternatives to OPC: Incorporation of Recycled Ceramics into Limestone Calcined Clay Cement
Lucia Ferrari, Anastasiia Nagmutdinova, Maria Chiara Bignozzi, Elisa FranzoniThe chapter delves into the sustainable alternatives to Ordinary Portland Cement (OPC) by focusing on the integration of recycled ceramics into Limestone Calcined Clay Cement (LC3). It begins by introducing the advantages of LC3 over OPC, including reduced CO2 emissions and enhanced durability. The study then examines the potential of ceramic waste materials, such as tile and roof tile residues, as viable constituents in cementitious formulations. The characterization of two specific ceramic waste powders (RC1 and RC2) is conducted, revealing their unique properties and how they influence the final material performance. The formulation of LC3 with these recycled ceramics is compared to a reference LC3 with calcined clay, assessing rheological properties through flow table tests and mechanical strengths at 2 days. The use of Time-Domain Nuclear Magnetic Resonance (TD-NMR) provides insights into the water distribution in fresh paste, while colorimetric analysis and mechanical strength tests offer a comprehensive evaluation of the hardened properties. The findings highlight the impact of particle size and specific surface area on rheological properties and mechanical performance, suggesting that finer powders enhance reactivity and strength. The chapter concludes by emphasizing the potential of recycled ceramics to improve the sustainability and performance of LC3, offering promising avenues for the construction industry.AI Generated
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AbstractLow-carbon binders, particularly Limestone Calcined Clay Cement (LC3), are emerging as sustainable alternatives to Ordinary Portland Cement (OPC). LC3 significantly reduces CO2 emissions, offering satisfying mechanical strength, increased durability, and reduced environmental impact. Simultaneously, the traditional ceramic production process generates residual powder that could serve as a viable cement substitute. Ceramic waste materials, including scraps, waste powder, sludge, and tile residues, may exhibit pozzolanic behaviour, making them valuable in construction materials.This research investigates potential benefits and challenges of incorporating grinding powders of porcelain stoneware into low-carbon cement. The LC3 formulated with recycled ceramic was analysed and compared to reference cement containing 50% of clinker and calcined clay to limestone proportion of 2:1. Mortar rheology was investigated by flow table test at different superplasticizer dosage and the fresh material was further investigated by 1H Time Domain-Nuclear Magnetic Resonance (TD-NMR) to detect the amount of capillary water available to fluidify the mixture. Colorimetric analysis was performed to quantify the visual impact of ceramic substituents on the material. Mechanical strength at 2 days enabled to validate the suitability of industrial waste to prepare eco-friendly mortar.The results show that the particle size distribution plays a crucial role in regulating superplasticizer need to reach acceptable workability. The TD-NMR findings validated that the cement composition influences the amount of detectable capillary water. However, the assessment of mechanical strength highlighted that ceramic waste can provides comparable performance to reference material encouraging the possible integration of recycled ceramics into low-carbon cement. -
Valorisation of Recycled Concrete Aggregates via Calcium Carbonate Precipitation Through Urease Enzyme Extracted from Watermelon Seeds
Snigdha Bhutange, Salman MuhammadThe chapter delves into the innovative use of crude urease extracted from watermelon seeds to treat recycled concrete aggregates, enhancing their properties through calcium carbonate precipitation. By treating the aggregates with urease, water absorption and total porosity are significantly reduced, leading to improved durability and strength. The study compares different treatment methods, including cement slurry and enzyme treatment at various temperatures, highlighting the effectiveness of the enzymatic approach. The research also provides insights into the extraction and activity measurement of the urease enzyme, demonstrating its potential for sustainable waste management in the construction industry.AI Generated
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AbstractThe current study attempts to utilize crude urease extracted from watermelon seeds along with urea and calcium source, for the treatment of recycled concrete aggregates. The experimental program involved extraction of urease in a phosphate-EDTA buffer to ensure the stability of the active sites of the enzyme. Its activity was assessed using spectrophotometric method. Subsequently, varying concentrations of this crude urease extract were used to treat recycled concrete aggregates at different temperatures. The results indicated a significant reduction in water absorption for the treated aggregates compared to untreated ones. Furthermore, image analysis of scanning electron images revealed a notable decrease in total porosities of the treated recycled aggregates compared to their untreated counterparts. X-ray diffraction analysis confirmed the presence of calcite, vaterite and aragonite polymorphs of calcium carbonate in the precipitates produced by the activity of the urease enzyme.
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- Title
- Proceedings of the RILEM Spring Convention and Conference 2024
- Editors
-
Liberato Ferrara
Giovanni Muciaccia
Niki Trochoutsou
- Copyright Year
- 2025
- Publisher
- Springer Nature Switzerland
- Electronic ISBN
- 978-3-031-70277-8
- Print ISBN
- 978-3-031-70276-1
- DOI
- https://doi.org/10.1007/978-3-031-70277-8
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