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2023 | Buch

Proceedings of the Canadian Society of Civil Engineering Annual Conference 2021

CSCE21 Materials Track

herausgegeben von: Scott Walbridge, Mazdak Nik-Bakht, Kelvin Tsun Wai Ng, Manas Shome, M. Shahria Alam, Ashraf el Damatty, Gordon Lovegrove

Verlag: Springer Nature Singapore

Buchreihe : Lecture Notes in Civil Engineering


Über dieses Buch

This book comprises the proceedings of the Annual Conference of the Canadian Society of Civil Engineering 2021. The contents of this volume focus on specialty conferences in construction, environmental, hydrotechnical, materials, structures, transportation engineering, etc. This volume will prove a valuable resource for those in academia and industry.


Analysis of Waste Glass as a Partial Replacement for Coarse and Fine Aggregates

There has been substantial intrusion of non-renewable resources including aggregates in concrete. On the other hand, waste glass accumulates to up to 20 million tons per year in Egypt alone. The main idea of this work is to explore partial replacement for both coarse and fine aggregate with waste glass. To meet this objective, ten mixtures were prepared using various dosages of waste glass as brought from landfill and grind in the lab. Experimental work includes fresh and hardened concrete have been conducted on these mixtures. Specialized tests, namely brightness and reflection, are conducted to explore architectural merits of such concrete incorporating glittery glass. Results reveal moderate to good concrete quality in almost all tests. Tests also pinpoint the architectural merits for using such concrete of glass waste. A simple feasibility study is also provided to examine the economic aspect of using such concrete in concrete industry.

Kirolos Wagdi, Mohab El-Dyasity, Nouran Gohar, Omar Assem, Sandra Ghaly, Youssef Mokhtar, Mohamed Abou-Zeid
Effect of Zycosoil as an Additive on VG30 Bitumenous Concrete

The expansion of urban population with the industrial revolution, increasing the high demand for vehicles coupled with highly efficient roads, unable to sustain extreme pressures of heavy traffic loads safely. India, the second pre-eminent country, in terms of, the largest road network of 55 lakh Km length in the world, having 98% of flexible and just 2% of rigid pavements with diverse climatic conditions that affect the properties of natural bitumen as a binder content in the flexible pavement, undergo failure and cause serious problems. In order to ameliorate this complication, bitumen modification is required to enhance its properties for better serviceability with regards to the pavement surface. Recently invented Nanomaterial namely Zycosoil a chemically reactive anti strip additive used to check the strength characteristic of bitumen. The present paper, hence, exhibits the studies of effects of Zycosoil on the physical properties of modified and unmodified bitumen (VG 30). An optimum bitumen content by Marshal Mix Design which attained maximum stability was evaluated, without and with required dosages of Nanotechnology Zycosoil chemical such as 0.03%, 0.04%, 0.06% and 0.07%. Further, comparisons were made between neat bitumen (VG 30) and Zycosoil modified bitumen for physical and Marshall properties. As per result of this study, even though Zycosoil modified bitumen when put to penetration, softening point and ductility tests showed altered properties but overall, Zycosoil inclusion had an insignificant effect on physical properties. Next to this, Marshall results in exhibits that incorporation of Zycosoil with bitumen imparts marginal strength as compared to the neat bitumen, albeit at small scale as per dosage. From mixtures, modified bitumen containing 0.07% Zycosoil demonstrated the utmost stability value. Therefore, 0.07% Zycosoil cooperation with bitumen at 5.3% optimum binder content exhibits the improved upgraded results for the mix that can be suggested for the construction of flexible pavement.

Sukhjinder Singh Kahlon, Gurpreet Singh, Gursharn Singh
Incorporating Carbon Dioxide into Portland Cement Concrete

The significant increase in the global carbon footprint is detrimental to the planet. Within this context, this study explores the possibility of trapping carbon dioxide into concrete in a permanent manner. The process of trapping carbon dioxide into concrete involves a chemical reaction between hydrated cement and carbon dioxide. This reaction results in the transformation of carbon dioxide into nano in-situ particles of calcium carbonate. Trapping carbon dioxide in concrete can be beneficial to both the environment as well as the construction industry since the strength properties of the resulting concrete are maintained, if not improved. To meet the objective of this study, various concrete mixtures were prepared, incorporating different forms and dosages of carbon dioxide. The produced concrete was assessed for its fresh concrete properties through tests such as slump, slump retention, temperature, unit weight, and air content, as well as hardened concrete properties such as compressive strength and flexural strength. The resulting concrete’s chemical properties were examined through specialized tests namely, chemical resistance analysis, pH meter, and Energy Dispersive X-ray Spectroscopy (EDX). This work provides a better understanding of the properties of concrete incorporating carbon dioxide along with potentially finding good ways of making use of carbon dioxide waste in the construction industry. The results show that carbon dioxide has been successfully trapped in the concrete mix, thereby contributing to a healthier environment by reducing the carbon footprint.

Sara El-Gamal, Habiba El Khouly, Shaden Fayek, Merna Mohamed, Gina Roupheil, Nada Aly, Athnasious Ghaly, Mohamed Abou-Zeid
Effect of Admixtures on the Performance of Anti-washout Concrete

Pouring underwater concrete has always been a challenge. It involves the use of a variety of techniques and equipment. Anti-washout concrete was introduced more than two decades ago to allow casting concrete underwater. This paper aims at investigating the effects of various mineral and chemical admixtures on the properties of underwater concrete. Performance-enhancing admixtures are used herein to produce quality concrete that can be used in the construction of submerged structures like harbors, bridges and other maritime projects as an alternative to the traditional methods. Concrete mixes were prepared involving different combinations of polypropylene fibers, nonionic cellulose ethers, high range water reducer, silica fume, fly ash, natural zeolite, limestone, and bentonite powder. Viscosity modifying agents and super-plasticizers were optimized to clearly study the effects of mineral admixtures. Each mix was poured from the surface of water and traveled 400 mm into the molds. The concrete was compacted under its own weight and no compaction energy was induced to examine the effect of flowability on self-compacting properties and washout loss. Fresh and hardened testing was conducted to examine durability, flowability, and washout resistance of concrete. The results suggest that adding rheology modifying admixture nonionic cellulose ethers (0.7–1.0%) combined with a dosage of the high range water reducer (5–11%) and maintaining a silica fume percentage of (12%) can result in a concrete mix that has good flowability and washout resistance. This is the first-time natural zeolite has been tested in anti-washout concrete. Results reveal that using a combination of silica fume along with natural zeolite can result in a relatively high-quality anti-washout concrete strength.

Ahmed Abbas, Ahmed El-Wakil, Eslam El-Basel, May Hassan, Nada Abo-ElMagd, Yasser Kilany, Aya El-Desouky, Magdi Madi, Mohamed Abou-Zeid
Thermally Controlled Concrete Incorporating Waste Materials and Byproducts

Global energy consumption has drastically increased over the past years. A huge percentage of this increase tracks back to the buildings and construction industry. A bulk of this energy denotes to providing a suitable indoor environment for the structure. The thermal properties of the structural elements of a building are highly overlooked in the construction industry. Thus, this study aims at shedding light on the possible utilization of the thermal properties of concrete by exploring its thermal behavior upon incorporating three different materials with various dosages without compromising its mechanical behavior. Firstly, blast furnace slag was used to produce and test potentially conductive concrete. Secondly, incorporation of spent coffee grounds is explored in order to improve the insulating properties of concrete, which can contribute to alleviating environmental drawbacks. Moreover, the third material considered was paraffin wax, a phase changing material (PCM), which utilizes thermal energy storage. The work is expected to highlight the utilization of thermal properties of concrete in the construction industry. Furthermore, it shall assess the possible introduction of the aforementioned materials in the construction market for the purpose of producing thermally controlled concrete. The testing scheme targets fresh and hardened concrete properties as well as thermal conductivity. A data logger is used to evaluate the thermal properties of the materials in miniature chambers. Results revealed a good potential for the use of such material in adjusting the thermal properties of the concrete produced. The ultimate goal of this research is to contribute to the assessment of concrete while in service based on its thermal behavior together with its other well-established properties.

Ahmed Badawy, Amr ElSabagh, Ahmed Farrag, Heba Gad, Mai Hassan, Sondos Mansour, Mariam Zaki, Hossam Zaher, Reem Abou Ali, Mohamed Abou-Zeid
Properties of White Portland Cement Concrete

White cement has been produced for several decades. Yet, it is only quite recent that designers have been expanding in its use in structural application for a variety of reasons. This includes its remarkable white color effect and its better ability for pigmentation by a set of colors thereby requiring less or no plastering. On the whole, white Portland cement has similar chemical composition to that of conventional grey cement with the exception of few oxides alterations. The question always remains as to how well such cement can perform in concrete load-bearing elements. This work aims at achieving better understanding of the properties of white cement when incorporated in concrete mixtures. To meet these objective, several types of commercially available white cement have been acquired and tested together with conventional grey cement. The testing scheme involved chemical analysis and fresh concrete properties such as unit weight, slump, temperature and air content. Hardened concrete properties were evaluated through compressive strength testing after 3, 7 and 28 days as well as flexural strength after 28 days. In addition, samples were made of pigmented concrete and were evaluated for thermal insulation and light reflection. A comparison was held to assess the sensitivity to pigmentation of each cement types. Results reveal that, overall, white concrete has good-to-high performance that can surpass grey cement. The mechanical properties, long term properties as well as environmental merits, all suggest that such cement should be applied on a wider scale in structural concrete and not only be limited to decorative purposes.

Riham Abuzaid, Mina Rofael, Salah ElGamal, Hussein Enaya, Mohamed Bahaa, Fady Akhnoukh, Mayer Farag, Reem Abou Ali, Mohamed Abou-Zeid
Porous Rubber Pavement—In Situ Performance Evaluation of Stiffness and Friction in Canada

Porous Rubber Pavement (PRP) is a relatively new material for low-trafficked pavements. This material consists of rubber aggregates, granite aggregates and polyurethane as a binder and is proportioned to attain a very high content of interconnected air voids. PRP has widespread environmental and safety benefits. While conventional impermeable paving materials interrupt our natural hydrological system by replacing natural soil surface, porous rubber pavement could reduce surface runoff, maintain the underground water table and improve water quality by its filtering capability. However, this low-impact design material is not currently widely used in pavements. Specifically, in Canada, its use is only limited to low volume traffic and low driving speed areas like parking lots and driveways. As a pavement material, its performance is still unexplored for the Canadian climate. Exhaustive research has been designed to investigate this material in this climate. This paper presents a part of the initial investigation of this material, which evaluates the performance of the existing PRP in terms of its strength and friction on the field. To examine the stiffness of this material, Lightweight Deflectometer was used. Friction is examined and compared using British Pendulum Tester and T2GO friction analyzer. The average Modulus of Elasticity of PRP is noted to be between 33 and 37 MPa that is significantly lower than conventional asphalt pavement. Average BPN was found to be between 57 and 74 and frictional values significantly reduced (almost 22%) under the wheel path. T2GO results also show a lower coefficient of friction value below 0.4 under the wheel path. Although both of the friction analyzing equipment show a similar trend, the T2GO produced more consistent results. The overall result shows that the stiffness of PRPs is considerably low as a pavement material. However, it exceeds the frictional threshold value for pavements. This study provides insight into the existing performance of PRP and the basis for future studies to improve its performance for broader pavement applications.

Tamanna Kabir, Abimbola G. Oyeyi, Hanaa Al-Bayati, Daniel Pickel, Susan Tighe
Effects of Chemical Parameters on the Fresh State Properties of CDW-Based Geopolymer Systems

The fresh properties of construction and demolition wastes (CDW)-based geopolymer pastes depend on various factors such as the contents of aluminosilicates in precursors, the combination of precursor powders and the contents of alkaline solutions and water. In order to quantify the effects of the aforementioned factors on the fresh properties of CDW-based geopolymer compositions, an algorithmic mix design method was employed based on precursors contents, liquid/solid (L/S) and synthesis chemical oxide values. This study presents the influence of SiO2/Al2O3 (Si/Al) and Na2O/SiO2 (Na/Si) molar ratios and precursors contents on the flowability and setting behavior of mono and binary geopolymer systems prepared with red clay brick waste (RCBW), ceramic tile waste (CTW) and concrete waste (CW). Binary systems were adjusted to include precursors contents between 20 and 80%. The results confirmed a high correlation between the oxide ratios and the followability and setting times of geopolymers, though the same L/S ratio was used for all compositions. Overall, increasing Si/Al and Na/Si ratios resulted in increased flowability. In addition, increased ratio of Si/Al resulted in increased setting times; while increased Na/Si caused the setting times to reduce. It was determined that Si/Al was more influential than Na/Si on the flowability of geopolymer pastes. However, the effect of Na/Si was more dominant on setting times compared to Si/Al ratio.

O. Mahmoodi, H. Siad, M. Lachemi, M. Sahmaran
Mechanical Performance of the Composite Concrete System Under Fire Exposure

This paper investigates the performance of composite systems combining self-consolidating concrete (SCC) and normal strength concrete (NSC) under fire exposure. SCC was used in the compression zone while NSC was overlaid in the tensile zone. The resulting systems were exposed to high temperatures ranging from 23 to 800 °C. Two types of cooling regimes have been considered i.e. water and air cooling. The primary objective of the study was to analyze the interfacial bond deterioration and the variation in mechanical strength. Test results indicated that the mechanical strength and mass decreases with rise in exposure temperature. The interface remained intact without excessive damage. Further, the thermal shock experienced during the water cooling negatively impacts the composite system.

Waqas Latif Baloch, Hocine Siad, Mohamed Lachemi, Mustafa Şahmaran
Mechanical and Durability Properties of Fly Ash Blended Concrete with Gi Fiber

Over the last few decades, the global production of building materials has increased. Concrete is one of the highly used construction materials and in recent year different types of concretes are prevailing. Fly ash blended concrete with galvanized iron (GI) fiber is a type of concrete in which the cement can be partially or fully replaced by fly ash. This study investigates the influence of fly ash and GI fiber on the engineering properties of concrete by replacing different percentages of cement (5, 10 and 15 by weight) with fly ash and by adding 0.5% (by volume) GI fiber into the concrete. Workability, compressive strength, splitting tensile strength, flexural strength, stress strain response under axial compression, durability at high temperature are the engineering properties that have been investigated. It was found that concrete up to 15% fly ash and fiber showed better result of compressive strength than concrete without fly ash and fiber. The splitting tensile strength was also found to be highest in concrete with 15% fly ash and 0.5% fiber. The flexural strength of fiber reinforced concrete with fly ash has been examined by loading concrete beams. According to the findings, increasing the percentage of fly ash and adding GI fiber improved flexural strength and changed the stress strain response of fly ash blended concrete with GI fiber from brittle to ductile. The durability test results showed that higher percentages of fly ash decreased the strength reduction between compressive stresses at high temperature (500 °C) and room temperature (25 °C).

Md Jahidul Islam, Nishat Tabassum Borsha, Nishat Naila Meghna, Rahi Bin-te Enam
Effect of Fiber Type and Length on the Mechanical Properties of Recycled Aggregate Concrete

Substantial volumes of concrete waste are generated every day from construction and demolition activities, and this has become a global concern from an environmental perspective. Recycled aggregate generated as a by-product of construction and demolition waste can be used as an alternative to natural aggregates, which are being depleted in many countries, including Bangladesh. Although recycled aggregate has lower density, higher water absorption, and lower mechanical properties compared to natural aggregate, the incorporation of fiber in recycled aggregate mixes can improve the mechanical properties. This study investigates the physical and mechanical properties of recycled aggregate concrete reinforced with 0.51 mm diameter galvanized iron and 12 mm diameter polypropylene fibers. The test variables are fiber type and galvanized iron fiber length (15 mm, 26 mm, and 36 mm). Four different concrete mixes with 0.5% fiber content (by volume) are considered, along with one mix without fiber. Slump value, compressive strength, splitting tensile strength, flexural strength, and stress–strain behavior are analyzed and compared. The results indicate that the inclusion of fiber significantly reduces the workability of concrete. However, it enhances the mechanical properties of recycled aggregate concrete compared to the control concrete. Concrete mixtures containing galvanized iron fibers with lengths of 26 mm and 36 mm show the highest strength among the five mixes under study. However, concrete mixtures reinforced with shorter lengths of fibers are found to be more workable.

Khatun Ehsani, Islam Kamrul, Islam Md Jahidul
Reliability Analysis of Slope Stability Using Censored Samples and Genetic Algorithm

In geotechnical slope stability analysis, soil properties have a great extent of randomness and thus are extremely amenable to comprehensive probabilistic treatment. The randomness of soil parameters is involved in slope analysis using probability distributions. Due to technical and economic reasons, it is sometimes difficult to collect complete information of soil properties in full or non-censored domain. In such special cases, the analysis of slope stability needs to be conducted with truncated random variables, which are characterized by truncated probability distributions. The contributions of the extended abstract include twofold: Firstly, censored samples are used to determine truncated probability distributions based on the principle of maximum entropy and Akaike information criteria, which is the least unbiased as it is derived from a systematic maximization. Secondly, the truncated probability distributions obtained are implemented in a first order reliability method to calculate the probability of failure or reliability index of geotechnical slopes. Genetic algorithm is used to tackle the problem of convergence that arises in the usual iterative algorithm of the first-order reliability method when one or more of the random variables are described by truncated probability functions. The application of the proposed method is demonstrated by performing reliability analysis of a slope with censored samples to determine the probability of failure.

S. Yerra, J. Deng
Application of Artificial Neural Networks (ANNS) in Prediction of Compressive Strength of PCM-Integrated Concretes

Phase Change Materials (PCMs) have been proven to enhance the thermal performance of cementitious composites owing to their thermal energy storage (TES) capacity. Nevertheless, they can hamper the compressive strength of the concrete. Several pertinent factors have a complex and non-linear negative influence on the compressive strength, and thus it is difficult to model the mechanical strength development of such composites using conventional statistical procedures. Therefore, this study explores the feasibility of using Artificial Neural Networks (ANNs) to predict the compressive strength of cement mortar and concrete integrating PCM microcapsules. For this purpose, a dataset comprising 160 examples of mixture proportions and 10 input features is used to create the ANN model. The dataset is currently the largest that could be extracted from studies in the open literature. Several statistical metrics are used to evaluate the performance of the proposed model. It is demonstrated that the developed ANN has a very promising capability in predicting the compressive strength of cementitious composites incorporating PCM microcapsules with desirable accuracy.

Marani Afshin, Nehdi Moncef L
Climate Change Adaptation of CSA Standards for Masonry Connectors

During a recent review of its standards, the CSA Group identified CSA A370:14 Connectors for masonry as a high priority for modification and adaptation to climate change. This assessment was based primarily on the inclusion of annual Driving Rain Index (aDRI) values in the standard for various locations in Canada. These aDRI values are an important factor in the determination of corrosion protection requirements for masonry ties. Research has shown that climate change has resulted in altered precipitation patterns in some regions in Canada, and models forecast these changes to continue in the future; a review of the design requirements for corrosion resistance of masonry ties is therefore warranted. A research team from York University is currently engaged in a review of current CSA masonry standards with the goal to provide recommendations for climate change adaptation to CSA standards committees for the next round of standards updates. This review paper specifically includes an overview of the state of current knowledge regarding sources of moisture in masonry wall cavities, and factors affecting the corrosion of masonry ties. A comparison with how other CSA and international standards provide guidance to designers on appropriate protection from moisture-related deterioration is also included. Recommendations arising from this review include guidance to designers on accurate methods for determining the expected service life of galvanized steel masonry ties (accounting for climate change) and updated simplified guidance on minimum corrosion protection for connectors. These recommendations will help better prepare masonry construction for the effects of future climate change.

A. Sparling, D. Palermo, U. T. Khan
Influence of Various Recycled Aggregates on the Compressive Strength, Thermal Conductivity, Water Sorption and UPV of Fibre-Reinforced Composites

In order to improve the energy efficiency of buildings, there is a need to develop and utilize composites with good thermal, mechanical and durability properties in the construction of buildings. Comprehensive development and evaluation of energy-efficient fibre-reinforced composites for the construction of building walls are being undertaken at the University of Windsor. This paper presents some preliminary results on the influence of various recycled aggregates on the compressive strength, thermal conductivity, water sorption and ultrasonic pulse velocity (UPV) of the developed composites. In this study, a high volume of Portland cement was replaced with fly ash, and recycled concrete, recycled asphalt, recycled glass, and recycled rubber were used as a total replacement of the natural aggregates. The results of this study showed that the sustainability and thermal properties of fibre-reinforced composites can be improved with the utilization of recycled aggregates. However, there could be a slight detrimental impact on the compressive strength of the composites due to their lower stiffness/high water absorption. Nonetheless, fibre-reinforced composites with good mechanical and durability properties can be produced with recycled aggregates and used for the construction of walls in buildings in order to improve the energy efficiency of buildings.

Adeyemi Adesina, Sreekanta Das
Flexural Characteristics of Fibre-Reinforced Alkali-Activated Composites

The need for environmentally friendly and high-performance composites for various construction and rehabilitation applications has resulted in the use of alternative binders and reinforcements. In this study, fibre-reinforced composites were made with lime-activated slag/fly ash as the binder and Polyvinyl alcohol (PVA) fibres as reinforcement. The fly ash was used as 0, 50, and 100% replacement of the slag and the corresponding performance of the composites evaluated in terms of the flexural and crack properties one year after they were made. The flexural properties evaluated are flexural strength, deflection and toughness. Image analysis was used to assess the crack properties and results presented in terms of the crack widths and areas. The findings from this study showed that alkali-activated binders can be utilized to produce fibre-reinforced composites for various construction and rehabilitation applications. It was also evident that the use of fly ash as a replacement of slag in the binder resulted in an increase in the ductility of the composites. However, higher content of slag resulted in higher flexural strength. Nonetheless, findings from this study showed that the content of fly ash used as a replacement of slag can be optimized depending on the performance required.

Adeyemi Adesina, Sreekanta Das
Performance of Steel Kerf Plates as Shear Connector for Cross-Laminated Timber-Concrete Composite Systems

In this paper, experimental investigations of the performance of Timber-Concrete Composite (TCC) systems with steel kerf plates as shear connectors are presented. The stiffness, strength, and failure modes of small-scale TCC specimens with steel kerf plates were evaluated in quasi-static monotonic tests. The specimens were comprised of 245 mm thick, 7-ply CLT panels with 150 mm concrete topping connected with steel plates. The embedment depths of the steel plates in the CLT were varied from 35 to 90 mm to investigate the performance variation. Eighteen tests were conducted with six replicates from each type. The load-deformations and connector slips at the CLT-concrete interfaces were measured. Results showed that load carrying capacity and stiffness of all test series were comparable and that the shallow 35 mm steel plate embedment depth into CLT resulted in sufficient composite action for the TCC composites. The steel kerf plates showed excellent performance and can be deemed a promising and economical solution for shear connectors in TCC members.

Md Shahnewaz, Robert Jackson, Thomas Tannert
A Few Mechanical and Flexural Properties of Brick, Recycled and Natural Aggregate Concrete

The need for finding sustainable alternative sources of coarse aggregates as an ingredient for concrete has been increasing globally. Recycled and brick aggregates are two viable options in this regard. Many properties of recycled and brick aggregate concrete remain to be investigated to predict their behaviour accurately and to set proper code guidelines. In this study, a few properties of recycled and brick aggregate concrete and their behaviour in flexural members have been investigated. In particular, the stress–strain relationship, modulus of elasticity and splitting tensile strength of concrete made of brick, recycled and natural aggregate have been analysed. Using these properties, some of the flexural properties of reinforced concrete members made with these three types of aggregates have been determined and compared. To the best of our knowledge, for the first time, a comparative analysis of these properties of brick, recycled and natural aggregate concrete has been conducted in this study. Results from the study show that while the code equations for predicting some of the important mechanical properties of concrete are suitable for natural aggregate concrete, they are not appropriate for recycled or brick aggregate concrete. The moment–curvature response and deflection properties in flexural members made of recycled and brick aggregate concrete are affected by the difference in the properties of the aggregate. Finally, it is suggested that the utilization of recycled and brick aggregate in concrete is likely a feasible option without any significant degradation in the mechanical and flexural properties of the structural members.

Mehsam T. Khan, Anindya S. Saha, Khan M. Amanat
Reducing Concrete Drying Shrinkage Using Superabsorbent Cellulose Fiber

The presence of shrinkage cracks in concrete is one of the major issues affecting concrete durability. Loss of moisture, changes in temperature, and hydration process are few reasons that cause shrinkage cracks in concrete. Among all types of shrinkage, drying shrinkage contributes a major portion of shrinkage strain in conventional concrete. Various parameters that affect the drying shrinkage of concrete are the element thickness, porosity, paste volume, fineness of the binder, water-cement ratio, fiber content, temperature, and relative humidity. The objective of this study is to develop a pulp fiber-based concrete mix that is capable of reducing concrete drying shrinkage. This study aims at developing a concrete mix that is acceptable for both its fresh and hardened properties with low drying shrinkage and cracking. To achieve this objective, Superabsorbent Cellulose Fibers (SCF) derived from water-insoluble, lignin-free Softwood Kraft Pulp fibers is used in concrete mix as a percentage of the total weight of water and cement content. Concrete mix design is performed for a target compressive strength of 35 MPa for exposure class C-1. Mix proportions are systematically designed to capture all the variables that affect the fresh and hardened concrete properties. The microstructure of hardened SCF concrete is studied using Scanning Electron Microscope (SEM) images. Test results for both fresh and hardened concretes are analyzed prudently to define the optimum SCF content. It is expected that the outcome of this study will aid in reducing the drying shrinkage in concrete.

A. L. Hassan, A. H. M. M. Billah
Silicate-Based and Alkali-Free Accelerators for Shotcrete Applications: A Comparative Study

Rapid set accelerating agents are added to shotcrete mixtures to speed up the hydration process targeting short setting time and high early strength. Silicate-based and alkali-free are the two main accelerating admixture categories that are being used in shotcrete. The effectiveness of these accelerators varies significantly based on the chemical composition of the binding material. Therefore, this study examined and compared the behaviour of shotcrete mixtures accelerated by silicate-based and alkali-free accelerators. Different accelerator dosages of 2, 4, and 6% by binder weight were tested. Flowability, and compressive strength development were evaluated. Results reveal that increasing the dosage had adversely affected the flowability of the mixtures. The threshold to achieve high strength was higher for silicate-based accelerator compared to that of the alkali-free accelerator. Based on the findings, it is recommended to contact trial batches to identify the optimum accelerator dosage based on targeted performance.

Esraa ElSayed, Ahmed Soliman, M. Hesham El Naggar
Concrete Repair with Alkali Activated Materials: A Review

Cement is the most used inorganic building material on earth due to its versatility and low cost. Its worldwide production in 2019 amounted to about 4.2 billion metric tons, which has a significant environmental impact. Around 8% of the global anthropogenic carbon dioxide (CO2) emissions are released from the cement production process. Under current ambitious environmental programs to achieve carbon–neutral buildings, cement industries are facing challenges. Several binding systems had been proposed as an alternative for ordinary Portland cement (OPC). These low carbon binders are showing promising performance in the area of repair and strengthening of deteriorating concrete structures. Hence, this study explores a review of the properties of various binding systems and successful repair applications. This is anticipated to provide engineers with more information about available alternative cement for repair and encourage them to use it as a replacement for cement.

Ahmed Khaled, Ahmed Soliman
Evaluating the Properties of Alkali-Activated Materials Incorporating Waste Materials Using Non-destructive Testing: A Review

In recent years, industrial waste disposal has become a major environmental issue. Researchers have reported several ecological, economic, and environmental benefits for recycling such wastes for making concrete. The addition of some wastes was found to improve concrete’s mechanical and durability performance due to their physical and chemical properties. On the other hand, the application of Alkali-Activated Materials (AAMs) as one of the best substitutes for the Ordinary Portland Cement (OPC) materials due to their long-lasting durability and low carbon emission can be a perfect solution for reducing the impact of construction industry on our environment. Although plenty of researches have focused on OPC materials incorporating such wastes, limited studies have explored their effect on AAMs. Furthermore, the application of Non-Destructive Testing (NDT) provides many advantages such as time and cost-saving for engineers to assess the structures in comparison with destructive testing. Among the studies on the AAMs incorporating wastes, there are few applications of non-destructive testing. Hence, this paper provides a review on the application of NDT on AAMs incorporating waste materials and compares the results with OPC materials. Moreover, the correlation between the destructive and non-destructive testing for AAMs incorporating waste materials is demonstrated. This study provides a basic knowledge for in-situ engineers to select a fast and convenient tool for evaluating the produced elements.

Farshad Meftahi, Ahmed Soliman
Effect of Various Temperatures and Relative Humidities on Crack Self-healing in Fiber-Reinforced Mortars Incorporating Crystalline Additives

In this study, the self-healing behavior of fiber-reinforced mortars incorporating crystalline additives under various temperatures and relative humidities was investigated. Optical microscopy, scanning electron microscopy with energy dispersive X-ray (SEM–EDS) analysis, were conducted to evaluate and characterize the self-healing. Pre-cracked reference specimens were cured underwater, while identical specimens were subjected to cyclic temperature and relative humidity. Results show that specimens incorporating crystalline additives exhibited more significant crack-healing after water submersion compared to that of the control specimens. In contrast, no considerable crack self-healing occurred in both control and specimens incorporating crystalline additives when exposed to cyclic temperature and relative humidity. SEM–EDS analysis confirmed that the main self-healing compound was calcium carbonate. It was found that the exposure environments of specimens played an essential role in crack self-healing.

Lei V. Zhang, Ahmed R. Suleiman, Afshin Marani, Moncef L. Nehdi
Structural Seismic Applications of Shape Memory Alloys: A Review

Shape memory alloys (SMAs) are metallic materials that possess superelastic properties and can undergo large deformations. There are mainly two types of SMAs that are commercially available in the market: NiTi-based alloys and Cu-based alloys, with the first being the most common. SMAs have the ability to return to their pre-deformed state through heating or stress removal due to a phase change in the material. Such service-mechanical properties are commonly known as shape memory effect, superelasticity, and hysteretic damping. SMAs are also known to have high-cycle fatigue resistance, corrosion resistance as well as high strength. Superelastic SMAs undergoing cyclic loading experience austenite–martensite phase transformations in its hysteresis. During the phase change, the elastic properties of the SMA increase. Through building and design, research and use of shape memory alloys have started to become more prevalent, including applications in structures located in seismic regions. The objective of this paper is to provide an overview of the applications of shape memory alloys in seismic-force-resisting elements of buildings and bridges in seismic regions. Several studies suggest that SMA technology significantly enhances the resistance to seismic loads and improves life cycle performance in structures. This makes SMA a promising alternative to conventional reinforcing steel since from the history of past earthquakes, civil infrastructures built across the world have proven to be susceptible to significant damage. Although the cost of SMA is higher compared to conventional construction material, implementing it into the structural design will resist drastic permanent deformations from seismic related activity and could prove to be beneficial considering the life cycle cost of the structure. Considering its superior self-centering property, there are many opportunities to investigate the use of SMA’s in civil structures in seismic regions.

A. Kandola, J. Wong, J. Bhandher, K. Cowan, S. Aldabagh
Analytical Investigation of Wood Material Properties on the Flexural Behaviour of FRP Reinforced Glulam

An analytical investigation examining the effects of wood properties on the flexural behaviour of glulam beams with fibre reinforced polymers (FRPs) was undertaken. A total of three different wood tension-to-compression strength ratios were investigated along with simple and U-shaped FRP configurations. A Visual Basic Application (VBA) module was developed to conduct moment–curvature analyses using published material models. Moment resistance increases of 1.95 and 1.19 were observed for members having tension-to-compression strength ratios of 0.5 and 2, respectively. The results also showed that the addition of FRP flexural reinforcement on members having a tension-to-compression strength ratio greater than one were the least effective, with the bending capacity being governed by the compressive strength in the wood. Moreover, the results also demonstrated that providing reinforcement beyond a certain limit did not contribute to a proportional strength increase.

Y. Vetter, M. Stakheiko, H. Chen, S. Siciliano, D. Lacroix
Predicting the Compressive Strength of Alkali-Activated Concrete Using Various Data Mining Methods

Civil engineers have always considered the use of new data technologies in the construction industry. Several methods were applied to the analysis and sort the available massive data targeting accurate prediction for the performance. With the advent of alternative binding systems to ordinary cement, developing a predictive model that can offset the limitation in available data is a must. Hence, the paper focuses on predicting the compressive strength for alkali-activated slag-fly Ash concrete. Various machine learning techniques, including support vector machine and the artificial neural network, will be applied and compared. Also, the accuracy of each method will be analyzed based on the coefficient of determination (R2), root means square error (RMSE), maximum absolute error (MAE). It is anticipated that fully utilizing such new predictive techniques will provide engineers with a useful prediction tool.

Mohammad Mohtasham Moein, Ahmed Soliman
Impact Behaviour of Alkali Activated Slag Concrete at Ambient and Elevated Temperatures

Protective concrete structures are considered to be non-traditional structures. They must satisfy the required criteria that qualify them to resist fire and impact loads induced by bombs. Alkali activated material (AAM) as a green alternative to ordinary Portland cement needs more investigations to ensure their suitability for such structures. In this study, the impact behaviour of alkali-activated slag concrete (AASC) at ambient and elevated temperatures was investigated. Results indicated the stronger the AASC, the higher the resistance for impact loads at ambient conditions. Conversely, at elevated temperatures, the weaker the AASC, the better the behaviour in terms of residual impact energy absorption capacity. This is ascribed to the difference in the degree of hydration products decomposition of at ambient and elevated temperatures.

A. Abubakr, A. Soliman, S. Diab
Effects of Fibre Type on the Performance of Fibre-Reinforced Alkali-Activated Slag Concrete

Alkali activated material (AAM) is attracting the attention of the scientific community. It showed outstanding mechanical properties comparing to that of the ordinary Portland cement (OPC) concrete. Moreover, concrete is a brittle material; hence, its behaviour under tensile stress is more critical, specially, under dynamic loads such as impact loads. Many techniques were proposed and tested to improve OPC concrete tensile strength such as fibre incorporation. However, more studies are still needed to ensure the compatibility of these techniques with AAM. In this study, the effects of different fibre types (Steel, Basalt, and polypropylene fibres) and dosages, along with AAM activator natural on the cracking tendency under loads were investigated. It was found that steel fibre can achieve relatively better performance compared to other fibres at the same incorporation level. The activator natural did significantly affect the mode of fibres failure (i.e. rupture or pull out).

A. Abubakr, A. Soliman, S. Diab
Characterization of the Clay and Fibres for Hygrothermal Modelling

Ecomaterials used in traditional construction are experiencing renewed interest for their low environmental impact. However, the lack of reference values for the hygrothermal behaviour of some composite ecomaterials with a low carbon footprint prevents the overall analysis of the structures of buildings designed with these materials. The wood-clay construction system is an ecological and sustainable building system. These materials have great potential for applications in places where housing needs are high, in rural areas of Africa, and have been used for hundreds of years in Europe. The plant fibres improves the hygrothermal, mechanical and weather resistance performance of clay materials. This study determines the water content absorbed by the wheat and corn stalk fibres that will allow the water/clay ratio to be adjusted. For the characterization of red and white clay, the results obtained by the pycnometer method show that the bulk density of the clay is 2.80 and 2.73 with an absolute density of 2.79 g/ml and 2.72 g/ml. The results of the characterization of wheat and corn fibres show that they have the capacity to absorb more than 200% and 120% water by weight in only 25 min respectively at 23℃. The water absorption of fibres increases with increasing temperature. This increase contributes to the improvement of the hygrothermal performance of the materials by the restitution of the absorbed humidity, providing a very good feeling of comfort. Samples formulated with 0% to 3% wheat fibre have shown that the addition of fibre reduces the shrinkage of clay materials by 6.35 to 1.53%.

A. Kaboré, C. Ouellet-Plamondon
Effect of Mortar Consistency on Microencapsulated Phase Change Materials (MPCMs) Stability

Energy consumption is one of the challenging dilemmas the world faces now, with the endless growing economy and uprising technologies. Phase change materials (PMCs) are incorporated in construction material to control temperature fluctuation and reduce energy consumption. However, it was reported that a significant amount of PCMs is destroyed during mixing. This study aims to incorporate micro-encapsulated Phase change materials (MPCMs) in Self-compacting mortar (SCM) to examine its behaviour during mixing, mechanical behaviour after hardening, and thermal properties. Results showed improvement in the viscosity and thermal storage in the SCM.

O. Abdel Rahman, A. Soliman
Investigation of the Effects of Long-Term Aging and Testing Temperature Sensitivity on the Flexibility Index (FI) Parameter Obtained from the Illinois Flexibility Index Test (I-FIT)

Fatigue cracking, occurring at intermediate temperature, is the most prevalent mode of cracking in asphalt pavements. Due to recent significant progress in laboratory characterization of asphalt mixtures, testing notched specimens such as the one required by Illinois Flexibility Index Test (I-FIT) have shown promising to characterize intermediate cracking resistance of asphalt mixtures. I-FIT as per AASHTO TP124 standard was developed to assist in the asphalt mix design process, and at production level as a quality assurance tool. Since I-FIT is specified to be conducted at 25ºC, the effect of temperature sensitivity on I-FIT results is of interest. Currently, AASHTO R30 standard specifies forced-draft oven aging at 85ºC for 120 h of compacted asphalt mixture specimens for simulating long-term aging of asphalt pavements during service time. In this research, five plant-produced surface course asphalt mixtures that have been paved across Ontario were selected. The mixtures included asphalt binder grades of PG52-40, PG58-34, PG64-34, PG64-28, and PG70-28. First, the effect of two different laboratory forced-draft oven aging on I-FIT, at 85ºC for 120 h and at 95ºC for 72 h, was investigated. The statistical analysis of the results showed that both aging methods have comparable FI (Flexibility Index) values for five asphalt mixtures. Secondly, I-FIT was conducted at three temperatures, including 23ºC, 24ºC and 25ºC, to investigate the sensitivity of I-FIT parameters to testing temperature variations. The statistical analysis of the results showed that asphalt mixtures containing hard asphalt binders are more sensitive to the drop of testing temperature.

Saeid Salehi-Ashani, Susan Tighe
New Technology for Drying Wood Using Quicklime

There are several methods of drying wood however, each of them has its implications. This study involves a new method of drying wood which is fast, zero energy consumption, more economical and scalable. This method involves drying wood using quicklime. Raw Casuarina wood was placed in pits containing quicklime. One pit had one plank of wood and the other pit had four planks of wood. The absorption of water by the quicklime is the main idea of choosing that method to dry wood. The moisture content of the wood in both pits was measured every two days for ten days. The moisture content dropped from above 40% to 18%. To further reduce the moisture content, the same experiment was repeated with the same duration of ten days but after five days the quicklime was replaced. This has increased the rate of decrease of moisture content and dropped the moisture content from above 40% to 13%. In addition, the wood beams were graded according to the European standard of appearance grading of Oak. The wood produced through the drying method using quicklime resulted in an acceptable quality that can be used in the construction industry with a moisture content of 13%.

Mohamed Darwish, Ramy Azer, Azmy Azmy, Abdelrahman Hegazy, Sherif Elleissy, Ahmed Ahmed, Ahmed Morsi, Khaled Nassar, Passant Youssef
Influence of Wall Thickness on the Thermo-Mechanical Properties of Aging HDPE Pipes Under Freeze–Thaw Cycles in Quebec Province, Canada

The present study addresses the question of what effect wall thickness would have on the thermo-mechanical properties of corrugated HDPE pipes aging under freeze–thaw cycles in Quebec province, from the surface to its interior. Five commercial corrugated HDPE pipes for transportation infrastructure applications aging within 14 years from different locations in Quebec province (Canada) were examined. The impact of wall thickness (4.50, 7.00, 7.80, 8.90, and 10.40 mm) on decomposition, thermal properties, and long-term modulus of pipes was reported by thermal analysis techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Dynamic Mechanical Analysis (DMA). The antioxidant depletion at the exterior and interior walls of pipes was investigated by oxidation induction time (OIT) measurements. The results indicate that all investigated pipes meet a minimum 20-min OIT requirement where the antioxidant content is sufficient to withstand oxidation. The antioxidants extraction process occurred through the wall thickness which explains the significant difference in the thermal properties of pipes at the exterior and interior walls. However, the change of long-term modulus to variable wall thickness is relatively small.

Khanh Q. Nguyen, Patrice Cousin, Khaled Mohamed, Mathieu Robert, Brahim Benmokrane
Properties and Performance Metrics of Healing Agents in Self-healing Concrete

Self-healing concrete is evolving throughout the years to address concrete’s shortcomings, specifically the development of cracks due to low tensile strength. Encapsulation, a technique first developed for self-healing polymers, has been adapted to self-heal concrete. The success of encapsulation to autonomously self-heal cementitious material is highly influenced by the mechanical properties of the cementitious material, mechanical and geometrical properties of the capsules, as well as various properties of the healing agent. The aim of this study is to develop a design methodology for selecting the healing agents most suited for the application. Accordingly, the healing agent properties will be assessed for their viability and adequacy based on structural compatibility with the cementitious matrix. The healing agent properties of polymers include rheology, chemical kinetics, bond strength, stiffness, and crack-bridging of hardened agent.

Mouna A. Reda, Samir E. Chidiac
Analytical Study on Predicting the Shear Resistance of Steel Fiber Reinforced Concrete Beams

This paper presents a literature review on the shear behaviour of steel fiber reinforced concrete (SFRC) and proposes equations for predicting the shear resistance of SFRC beams. First a large database of test results is used to evaluate the effect of various parameters on the shear response of SFRC beams. In addition, the paper reviews various equations proposed in the literature to predict the shear capacity of SFRC beams. The paper then presents equations which can be used to predict the shear resistance of SFRC beams. The shear resistance equations modify the general method of the 2004 CSA A23.3 Standard to account for the effect of steel fibers on shear capacity. The method proposed in this paper and equations proposed in the literature are used to predict a large database of SFRC beam test results. The results show that the method presented in the paper provides reasonably accurate predictions of shear capacity for beams having a wide range of properties.

Michael Cohen
Developing a Novel 1D-HAM Numerical Modelling Tool for Assessing the Hygrothermal Properties of Cross-Laminated Timber (CLT) Including Adhesive Layers

Although cross-laminated timber (CLT) has been used in Europe since the early 1990s, the building material is relatively new in the North American market. CLT is an engineered wood product composed of dimensional lumber adhered in orthogonal layers. During service, CLT products are susceptible to moisture cycles which can lead to short-term performance and long-term durability issues. Numerical software packages such as WUFI are traditionally used to investigate the hygrothermal performance of CLT materials; however, these programs do not consider the impact of adhesive layers on air and moisture transfer. The purpose of this study is to develop and validate a novel 1D heat, air and moisture (HAM) numerical modelling tool that considers the impact of the adhesive layers on the moisture and air transfer in CLT. This paper establishes a novel methodology for the hygrothermal analysis of CLT products which includes the impact of adhesive layers. The methodology and model are validated using existing WUFI software and the simulation of CLT without adhesive layers. The results of the analysis show that the adhesive layers slow the rate of moisture transfer within the wood layers bounded by adhesives. Future research includes a study and analysis of the hygrothermal impact of adhesive layers in CLT in specific climate conditions as well as further validation of the model using laboratory and field testing.

Y. Vyas, D. Johns, R. Richman, Z. Liao
Hygrothermal Analysis of Cross-Laminated Timber (CLT) in Canadian Climates With and Without Adhesive Layers Using a 1D-HAM Numerical Modelling Tool

Cross-laminated timber (CLT) construction in Canada is becoming increasingly popular, however, due to a lack of local mass timber building precedents and minimal hygrothermal testing and research, the durability of the product in Canadian climates is a source of concern. Current 1D HAM (heat, air, and moisture) modelling softwares used to analyze the hygrothermal performance of cross-laminated timber (CLT) do not account for the adhesive layers integral to the composition of CLT. The purpose of this study is to investigate the impact of adhesive layers on the moisture and air transfer in CLT through the use of a novel HAM 1D numerical modelling tool. The development and verification of the 1D HAM numerical modelling tool utilized for this study was completed by Vyas, et al. To further Vyas’ research, this study investigates the impact of adhesive layers on the hygrothermal performance of CLT in a range of Canadian climate conditions. The analytical model was used to test 3-layer and 5-layer CLT with and without adhesive layers in order to determine the impact of adhesive layers on the hygrothermal performance of CLT situated in Toronto, ON, Vancouver, BC, Calgary, AB, Yellowknife, NWT, and Halifax, NS. The results of the analysis show that the adhesive layers slow the rate of moisture transfer within the 3-layer and 5-layer CLT and that the direct exterior climate conditions do not have a significant impact on the hygrothermal performance of CLT in service when insulated on the exterior. The impact of adhesive layers on the long-term durability of CLT requires further validated through laboratory testing and long-term field testing.

D. Johns, Y. Vyas, R. Richman, Z. Liao
The Effects of Aggregate Properties on Concrete Mix Design and Behaviour

Due to the fact that aggregates are the largest component in concrete (typically 60–70% by volume), the characteristics of the aggregates significantly affect the performance properties of fresh and hardened concrete. This article reviews the literature on the effects of coarse aggregate type on the mix design of concrete. Key parameters are identified, and a chart is plotted to help organize them. The relevant characteristics of aggregates are categorized into physical characteristics and geological characteristics. It is found that shape, texture and gradation have the most important role on the properties of fresh concrete, particularly workability. The porosity of the aggregate is reported to affect the workability during the first 15 min of mixing, as well as the creep and shrinkage. Depending on the mineralogy of the aggregate source, aggregates may react negatively with the matrix or beneficial interactions may occur between the matrix and the aggregates. Consequently, mechanical and strength properties of concrete can be affected by the aggregate mineralogy. Another important characteristic of aggregate is the presence and type of surface coatings which can affect workability and plastic shrinkage of concrete. Generally, an increase in dust content, increases the water demand of the mixture, which decreases workability and reduces air content. Aggregate type does not affect the setting time of concrete directly; however, the presence of soluble salts or organic contamination on the surface of aggregate may influence the setting time. Due to these impacts on the properties of concrete, adjustments to the mix designs are necessary when concrete suppliers are switching from one source of aggregate to another source.

A. Dehghan, M. L. J. Maher, M. Navarra
Experimental Assessment of Various Treatment Techniques for Enhancing the Properties of Different Types of Coarse Recycled Concrete Aggregate

The utilization of Recycled Concrete Aggregate (RCA) is becoming an exciting issue in Canada and globally, due to many reasons, including lowering consumption of natural materials, decreasing waste materials in landfills and reducing environmental problems. This research’s main objective is to investigate the effect of various treatment techniques on enhancing the physical and mechanical properties of two different Coarse Recycled Concrete Aggregate (CRCA) types. Heat treatment was performed at temperatures ranging between 250 and 750 °C. The presoaking method included the application of strong and weak acids represented by HCl and C2H4O2, respectively. The obtained results indicated that compared to untreated CRCA, a critical improvement is registered in the physical and mechanical properties of both types of treated CRCA due to the utilization of various treatment techniques. A significant difference is highly noticeable between CRCA#1 and CRCA#2 regarding physical and mechanical properties. The utilization of weak acid is more effective and suitable for all aggregate types. Of different treatments, the heat treatment at 350 °C had a maximum influence concerning enhancing various CRCA properties. The abrasion test results suggest that CRCA#2 has a lower amount of attached adhered mortar to the aggregate surface. Physical properties of CRCA, including water absorption and porosity, are strongly correlated with durability characteristics in terms of resistance to abrasion under the influence of heat treatment.

Hanaa Al-Bayati, Susan Tighe
Comparative Experimental Study of the Flexural Behaviour of UHP-SFRC and ECC Beams Reinforced with Smooth Bars

Research in seismic engineering continues to investigate the mechanical behaviour of various emerging and novel materials for application in a wide range of structural elements. This includes promising materials such as Superelastic Shape Memory Alloys (SE-SMAs) due to their self-centering properties, and high-performance concretes such as Ultra-High Performance Steel Fibre Reinforced Concrete (UHP-SFRC) and Engineered Cementitious Composites (ECC) due to their enhanced tensile deformation characteristics. Unlike traditional deformed reinforcing bars, the SMAs used in several studies for seismic applications are formed into smooth bars. This type of surface leads to reduced bond strength between the SMA and the surrounding concreting material used in a structural element. ECC and UHP-SFRC have demonstrated the ability to increase bond strength due to the presence of fibres in the matrix. This paper aims to quantify the effect of ECC and UHP-FRC on the flexural behaviour of beams reinforced with smooth bars based on increased bond capacity relative to beams with normal strength concrete. Two sets of beams consisting of ECC or UHP-SFRC reinforced with smooth bars were subjected to four-point loading. All beams were designed to ensure that flexural failure would occur in the constant moment region. Included in the experimental results was a set of control beams consisting of the same reinforcement but with normal strength concrete. The results demonstrated that the beams with ECC and UHP-SFRC provided improved flexural strength across all beams with deformed and smooth reinforcement relative to beams casted with normal strength concrete. In all tests, beams with UHP-SFRC provided higher flexural strength capacity than beams with ECC.

A. Martins-Robalino, D. Palermo
Mechanical Properties of FRCM at High Temperatures

Fibre-Reinforced Polymer (FRP) sheets are commonly used to increase the load-carrying capacity and stiffness of deficient structural members; however, there are concerns regarding the use of unprotected FRP in strengthening applications when exposed to fire. Fabric Reinforced Cementitious Matrix (FRCM) systems have emerged as a promising alternative for strengthening applications, replacing polymeric resins such as epoxy with an inorganic cementitious matrix. Although FRCM systems are generally expected to perform more favourably in fires because the cementitious matrix protects the fibres from direct exposure to elevated temperatures, limited experimental data is available to quantify the effect of temperature on its mechanical properties. This paper first presents a review of available literature on FRCM and identifies the parameters influencing the properties of FRCM at room and high temperatures. This sets the path for experimentally investigating the tensile behaviour of FRCM coupons under different heating regimes, namely: steady-state and transient temperatures. Progress is presented to-date on a study of the mechanical properties of carbon FRCM specimens, including tensile strength and modulus of elasticity, during exposure to elevated temperatures. The variables in the experiments include the number of layers of fabric (1, 2, 3 layers) in the composite test specimens, the thickness of the specimens (20, 30 and 40 mm), the fabric orientation (unidirectional vs. bidirectional), and the exposure temperatures. Results from a preliminary heating test shows a significant thermal gradient through the FRCM sample. The results are expected to enhance the understanding of the FRCM behaviour under heat effects.

H. Asghari, M. Noel, H. Hajiloo
Permeability Measurements of Reinforced Asphalt Overlays

Rutting, fatigue and thermal cracking are the most prominent pavement degradation observed in Canada. The presence of cracks on the surface allows water to seep into the pavement structure and accelerate its degradation. One of the options to remove cracks is to mill a thin layer and replace it with a new layer. Unfortunately, reflective cracking reappears very quickly on the surface. It is, however, possible to add a layer of reinforcement, a geotextile (paving fabric), or a geogrid that can help resolve this problem. The objective of this study is to investigate the effect of the addition of an impregnated paving fabric over a cracked surface. To do that, a new test was developed to simulate the crack propagation in the lab when a paving fabric is used. Permeability tests were then performed on cracked specimens to evaluate if the paving fabric can still function as a waterproofing layer even if the asphalt is cracked below and above it. Finally, rutting resistance tests were done to check if the paving fabric impacts this property. The results have shown that the developed test setup for cracking propagation with a paving fabric works very well. It was demonstrated that even with a crack width of 6 mm on the surface mix, the overall system remains waterproof, which means that water will not accelerate the pavement degradation. However, the rutting test has shown that the presence of paving fabric has a negative effect on the rutting resistance. Overall, the results show that the use of impregnated paving fabric over a cracked surface does increase the rehabilitated pavement performance.

Ehsan Solatiyan, Nicolas Bueche, Michel Vaillancourt, Alan Carter
Defects and Quality Control of Friction Stir Welded Joints in Aluminum Bridge Decks

Aluminum vehicular bridge decks figuhave been increasingly used for the replacement of deficient bridge slabs made from reinforced concrete or steel. The design of these decks has been under increasing development since the late 90s and different types of vehicular bridge deck profiles have been industrialized. Aluminum vehicular bridge decks are mainly manufactured through joining several extrusions together by means of welding. Initially, traditional fusion welding techniques were used in the fabrication process. However, more recently, a relatively new technology, friction stir welding (FSW), was used in certain bridge projects. FSW is proving to enhance the welding quality and the overall mechanical performance of the joint compared to traditional welding techniques. However, unlike fusion welding techniques, FSW standards and specifications still lack important quality control criteria and tolerance levels for common FSW defects. In this context, this paper aims at defining tolerance levels for common FSW fit-up defects in aluminium bridge deck application. First, FSW trials of typical vehicular bridge deck extrusions were conducted to determine the welding parameters yielding a sound welding quality. Then, fit-up defects such as gap and tool offset were investigated experimentally, and tolerance levels were determined following a concise stage prequalification process. It was found that a gap of 1.5 mm and a tool offset in the retreating side (RS) of 1.5 mm were acceptable limits. It was also shown metallographically that the level of the tool offset in the advancing side (AS) of 5 mm presented a sound weld quality with a continuous remnant oxide layer within the weld nugget.

M. Trimech, C.-D. Annan, S. Walbridge, S. Amira, F. Nadeau
Development and Volumetric Change Evaluation of Geopolymer Binders in Water Curing Regime

Geopolymer binders are developed through alkali activation of aluminosilicate-rich materials using alkaline reagents. This article presents the development of these geopolymer binders using a novel dry mixing technique incorporating powder-based reagents. The performance of developed geopolymer binder systems is assessed in terms of their strength and durability (volumetric change) characteristics. The effects of two binary combinations of supplementary cementitious (SCMs) with powder-based reagent and the fundamental chemical ratios (silicon dioxide: aluminum oxide, sodium oxide: silicon dioxide, calcium hydroxide: silicon dioxide and sodium oxide: aluminum oxide) on compressive strength and expansion/shrinkage in terms of length and mass change in water curing condition have been investigated. The length and mass change of all the binder prism specimens were observed at 1, 7, 28, 56 and 90 days post casting. The compressive strength of the mixes were also evaluated at 7, 28 and 56 days to derive their correlations with the length and mass change values. The mixture composed of binary SCMs combination (50% fly-ash class C and 50% ground granulated blast furnace slag) with multi-component reagent combination (calcium hydroxide: sodium metasilicate = 1:2.5) achieved a compressive strength of 41.5 MPa at 28 days and obtained lower shrinkage strains at 28, 56 and 90 days than its binary counterpart having a lower GGBFS content. All the binders exhibited a lower change in mass, expansion, and shrinkage strains after 56 days.

D. Sood, K. M. A. Hossain
Electrical Properties of Conductive Concrete Containing Graphite

Electrically conductive concrete has various potential non-structural functions such as self-sensing and electromagnetic shielding. Conventional concrete is a non-conductive composite, but electrical conductivity can be imparted and controlled by adding conductive additives. Since conductive concrete is a composite containing moisture and discrete conductive additives, the electrical properties of conductive concrete are very complex in nature. Understanding these properties are the fundamental requirements for developing its non-structural applications. In this research, graphite powder is used as a conductive additive for concrete with 3% by volume of cement paste. For characterizing the electrical properties, both AC (Alternating Current) impedance analysis and DC (Direct Current) measurement is performed in both wet and dry conditions, and their resistivities are calculated. The resistivity measured using DC increased with time of measurement. On the other hand, AC measurements show a consistent Bode diagram, but the resistivities decrease with the increase in AC frequency. These indicate conductive concrete with graphite is acting like a circuit containing a capacitor that stores electrical energy. Moisture plays a significant role in the electrical properties of concrete. The resistivity of concrete is lower in wet (saturated surface dry) conditions than in dry conditions. The results show that the electrical properties of conductive concrete cannot be represented by a single resistivity value and AC impedance spectroscopy is a useful method to characterize the electrical properties of concrete.

K. I. M. Iqbal, Paul Y. Choi, Nazmul Islam, Philip Park
Rubberized Alkali-Activated concrete—A Review

Over the past few years, the construction industry has entered new challenges in production. One of the main challenges is utilizing solid waste as aggregates to achieve environmentally friendly construction materials. Moreover, with the advent of alkali-activated materials, as a replacement of cement, more potential for achieving sustainability became possible. Hence, this paper highlights rubber's potential, as a replacement to natural aggregate, in alkali-activated concrete. The paper discusses rubber effects on fresh, hardened, and durability performance of AAC compared to cement-based concrete. This information will be helpful in extending the use of rubber in construction applications.

Arman Hatami Shirkouh, Ahmed Soliman
Properties of Sustainable Self-Compacting Mortar Incorporating Limestone Filler

Limestone filler (LF) is a natural material produced from grinding calcitic-limestone rocks in fine powder. The LF usage in the self-compacting mortar (SCM) can lower its cost and resolve the LF disposal problem. Hence, This research’s primary purpose is to optimize limestone filler content in the SCM to maximize the SCM sustainability level without compromising its properties. Limestone filler was used as a partial replacement of cement with percentages up to 15%. The fresh, hardened properties and hydration kinetics of self-compacting mortar were evaluated. Results show LF content improved early strength and hydration. Increasing LF content can reduce the adverse effect on the mechanical properties due to cement dilution.

O. Abdel Rahman, A. Soliman
Incorporation of Combined Rice Husk and Straw Waste in Concrete Production

The rice industry is one of the largest globally and it is one of the most grown crops worldwide, thus producing a significantly large amount of rice waste including straw and husk. The strategy of many countries to get rid of such waste is burning which causes adverse environmental effects as it increases emissions of greenhouse gases and causes severe health issues. This study aims at finding various forms of using rice waste in an adequate way to produce quality concrete without a large carbon footprint. Rice waste has been used in the form of rice husk ash, rice husk and rice straw fibres, both individually and combined. The rice straw fibres was added to mix as a percentage by weight of cement and the both the raw rice husk and rice husk ash were utilized as a cement replacement. Testing involved fresh, hardened, thermal testing as well as EDX analysis. Results revealed a good potential for the use of rice waste into concrete and an ability to minimize cracking. Conclusions and recommendations are provided for safe handling and minimization of negative environmental effects in producing concrete.

Zamel Serageldin, Gad Mohamed, Issa Abdelrahman, Al Ahmar Karim, Abdou Ahmed, Aboulatta Islam, El Kassas Hassan, Abou-Zeid Mohamed
On the Effect of Thermal Cycles on the Tensile Behavior of Rigid Fiberglass Geogrid

Studying the effect of temperature cycles on the mechanical behavior of geosynthetic material is essential for the analysis and design of reinforced soil structures in cold climate. High-strength fiberglass geogrids are relatively new soil reinforcement materials that have improved properties with a potential for a wide range of applications. This research involves a preliminary experimental investigation that has been performed to examine the effect of temperature cycles on the response of high strength biaxial geogrid material, namely stiff fiberglass geogrids. Single ribs of geogrid were subjected to different thermal cycles and a series of tensile tests were performed to measure the ultimate strength and strain at failure for each sample. The experimental results are compared and the differences in mechanical properties in each thermal cycle are highlighted. Results indicated that, for the temperature range used in this study, thermal cycles have minimal effects on the mechanical properties of stiff fiberglass geogrids. The results also showed that fiberglass geogrid presents superior mechanical properties with significantly lower strains at failure.

Shokr Mohamed, Meguid Mohamed, Bhat Sam
Stress Crack Resistance of Recycled and Virgin HDPE Corrugated Pipe for Transportation Infrastructure Applications

As the use of recycled high-density polyethylene (HDPE) corrugated pipes is interested in road-drainage systems, their long-term properties need to be clarified. Recently, a research project was initiated at the University of Sherbrooke in collaboration with Quebec’s Ministry of Transportation (MTQ) to evaluate the durability of recycled and virgin HDPE pipes. The present study presents the stress crack resistance (SCR) part of the project. Notched specimens were cut from two corrugated HDPE pipe liners 900 mm in diameter for SCR tests. The SCR tests were performed in water at three different combinations of pressure/temperature of 650 psi/80 ℃, 450 psi/80 ℃, and 650 psi/70 ℃ according to FDOT FM5-573. Two extrapolation methods, Popelar’s Shift Method (PSM) and Rate Process Method (RPM), were used to generate a failure curve for each product. The results show that the RPM method is more reliable and is used to estimate 100 years of pipe lifetime. At service conditions of 10 ℃ and 500 psi, recycled pipes guarantee 100 years of service life as virgin pipes.

Khanh Q. Nguyen, Khaled Mohamed, Patrice Cousin, Mathieu Robert, Brahim Benmokrane
Flexural Ductility of Concrete Beams Reinforced with High Strength Steel

This paper presents preliminary findings of a study of the flexural ductility of beams reinforced with ASTM A615 Grades 60 and 100, A706 Grades 60 and 80, or A1035 Grade 100 longitudinal steel bars. Moment–curvature relationships were generated for beams with reinforcement ratios varying between 0.3 and 1.5% with concrete compressive strengths between 30 and 90 MPa. Curvature ductility factors were computed. Regression analysis techniques were used to assess whether the ductility corresponding to a given mechanical reinforcement ratio were significantly different for the different steel grades. It is concluded that the curvature ductility factor is, in all cases investigated, essentially proportional to the inverse of the mechanical reinforcement ratio. The ductility factors for ASTM A615 Grade 100 reinforcement are markedly less than those for the other grades, suggesting that a more stringent target reliability index should be used to calibrate the resistance factor for ASTM A615 Grade 100 reinforcement.

Sohaib Akbar, F. Michael Bartlett, A. Maged Youssef
3D Printing Concrete Incoroprating Environmentally Friendly Materials

With the development, the world is experiencing, building methods have had to be innovated to maintain the demands of the new world. 3D printing concrete (3DPC) has demonstrated its potential advantages over traditional building methods. This project aims to explore the technology of 3D concrete printing application and the ways by which it can be innovated through the research of using environmentally friendly partial replacements for Portland cement. Portland cement is the main component in the mixtures used in 3D printing worldwide; however, while this technology is gaining momentum in developed countries cement has disadvantages as it contributes significantly to the increase of CO2 emissions for the construction process. Accordingly, this research aims to partially reduce the cement content with an environmentally friendly alternative. Proposed 3D concrete mixes were composed of Fly Ash, Silica Fumes and Ground Granulated blast-furnace slag (GGBS) or Water Hyacinth Ash (WHA). Properties of the 3D printed mixes are challenging to achieve as the 3D concrete should have a certain flow ability to not have extrudability or buildability problems. Through experimental work it was found that WHA 10% and GGBS 30% partial replacements samples had acceptable 28-day compressive strength results which could be recommended for more investigation and use in the future.

F. Said, D. Eldwib, M. Zaytoun, A. Abd Elsalam, M. Bakhoum, O. Elshehemy, R. Abou Ali, S. El-Gamal, M. Abou-Zeid
Effects of Different Patterns of Reinforcement Corrosion on Concrete Cover and Residual Strength in Aged Bridge Piers: State-Of-The-Art-Review

Canadian infrastructure is exposed to extreme climate conditions from temperature fluctuations and cyclic precipitations, which are expected to increase. The effect of climate change exacerbates the condition of aged reinforced concrete (RC) infrastructure exposed to multiple environmental deteriorating mechanisms in the presence of service loads. Over time, the increase of wet and dry cycles in the presence of de-icing agents leads to premature deterioration of aged infrastructure due to reinforcement corrosion. This is apparent in material degradation (cracking and spalling) and overall reduction in strength and resiliency of aged bridge piers. The damage degree and pattern of reinforcement corrosion that aged columns suffer from are variable. The objective of this paper is to review available research on the effects of different reinforcement corrosion levels and patterns on the degradation of the concrete cover, residual strength, stiffness, ductility and confinement of RC columns subjected to eccentric loads. This paper also reviews research methods utilized to evaluate concrete cover loss and residual capacity and confinement. The paper is organized as follows: (i) experimental, (ii) analytical and (iii) numerical studies that evaluate corrosion effects on RC columns in terms of residual strength, ductility, stiffness and confinement effect; (iv) estimation of concrete cover loss; (v) existing research gaps to evaluate performance of RC columns and future work to address them.

Dabas Maha, Martín-Pérez Beatriz, Almansour Husham
Impact of Climate Change on the Construction Industry in Egypt

Climate change is one of the most critical issues that need to be considered due to the massive effect that it is expected to have on different areas. However, through conducting primary research, it was noticed that this phenomenon was not the main concern for several individuals working in the construction engineering field. It was essential to start shedding light on this topic, and therefore, the main objective of this thesis project is to identify the long-term impacts of climate change globally and on the construction industry in Egypt in specific, with emphasis on a case study located in New Alamein City. The main impacts that this project is going to be based on are sea-level rise, carbonation, and an increase in temperature. The scope of this project includes assessing the main precautions that are currently being undertaken, especially in coastal areas, to overcome the effects of these specific impacts and to highlight and evaluate key actions to be taken by the construction industry through guidelines and provisions that can be introduced to the project specifications and the codes of practice. These guidelines will include some recommendations to the concrete mix design (such as increasing the concrete cover and decreasing the water to cement ratios), the type of breakwaters that can be used, a system of moisture insulation for foundations, and a system of thermal insulation for the building. This will be done through extensive research and through conducting experimental work.

Effat Aya, Moharram Raghda, Soliman Nouran, Zahwy Mariam, Abou-Zeid Mohamed
Design of Haul Road on Soft Soil Using 3D Cellular Confinement

The stability of haul roads at oil drilling pads, ports, and marine reclamation areas is paramount for the better performance and economy of the project. These roads are generally made on extremely soft soils with low CBR values like 2–3%. An increase in the truckload, unavailability of better construction material, and environmental conditions pose major challenges like wheel rutting, differential settlements, and deterioration. In this study, the performance of haul roads on soft soils reinforced with 3D cellular confinements (Geocells) has been studied. The analysis is done based on a simple linear elastic approach given in the Indian Roads Congress (IRC) code. 3D cellular confinement reinforced with available soft soil was used for soil strength improvement in unpaved haul roads.

Uma Chaduvula, Pathik Bhagat
Differential Settlement Effect on RC Framed Structures

Differential settlement could be triggered by many factors within the soil strata, including frost heave, seismic activities, collapse of sinkholes, poorly compacted soil, or adjacent excavation activities. Such activities result in an uneven relaxation within the soil, forming undesirable settlements and imposing stress conditions, which are unaccounted for in the design process. Ground settlements can inflict serious, and in some cases, irreparable damage to pre-existing structures. Understanding the impact such settlements could have on structural systems is vital in developing effective preventative measures that would help mitigate such effects. Hence, this study investigates the effects of the differential settlement on a reinforced concrete framed structure by examining the structural behaviour considering different spans and heights. The nonlinear behaviour of the structure is simulated through two-dimensional (2D) frame finite element simulations. The propagation of mechanical damage within the structural members and the plastic hinge formation with respect to the induced settlements are then analyzed. The affect of ductility on the frame’s behaviour is demonstrated, and comparisons with settlement tolerances proposed in literature are drawn to assess the effectiveness of these limits.

A. El Naggar, M. A. Youssef, H. El Naggar, A. M. El Ansary
Investigation on Bond Performance Between Basalt FRP Rebars and Recycled Aggregate Concrete

Bond development between rebars and concrete matrix is important for the reinforcing rebars to function effectively. In this research, a set of specimens were prepared to investigate the required development length for sand coated basalt fiber polymer bars (BFRP) embedded in recycled aggregate concrete. Samples with steel rebar were also prepared and tested and used as a reference. Two bar diameters for both steel and BFRP were tested (between 10 and 12 mm). Different embedment lengths were investigated in order to find the optimum development length for BFRP rebars. Recycled aggregate concrete mix with an average compressive strength of 40 MPa was used. The bond behavior of steel and BFRP bar was evaluated using the direct in situ pullout test. The paper investigates the effects of various parameters on bonding strength including embedment length, BFRP rebar diameter and effect of recycled aggregate concrete. The results show that sand-coated BFRP bars have adequate resistance to pullout.

Samer Al Martini, Nabil AL Mzayyen, Reem Sabouni, M. Shahria Alam
Proceedings of the Canadian Society of Civil Engineering Annual Conference 2021
herausgegeben von
Scott Walbridge
Mazdak Nik-Bakht
Kelvin Tsun Wai Ng
Manas Shome
M. Shahria Alam
Ashraf el Damatty
Gordon Lovegrove
Springer Nature Singapore
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