Journal of Building Materials and Structures

Numerical Investigation of Fracture Behavior for Glass Fiber Composite Concretes

Meryem Charef — 2024-12-31

Waste aggregate-based composite cementitious materials preserve natural resources and reduce environmental concerns throughout green concepts. In this view, recycled waste aggregate-based concrete and its innovative design require advanced computational modeling techniques. Accordingly, this comprehensive and computational research is conducted to investigate the fracture behavior of notched glass fiber reinforced concrete beam modeled with finite element method. The impacts of substitution ratios of the waste on strains and crack opening displacements of validated beam models are investigated and argued.

Effect of Curing Methods on the Mechanical Properties of Cement Mortar Contaminated with Heavy Crude Oil

Rajab Abousnina — 2024-12-31

Crude oil contamination poses significant environmental issues, particularly in regions where oil spills affect soil and groundwater. Utilising damaged materials in construction offers a cost-effective rehabilitation strategy that repurposes waste and reduces pollution. This study examines the effects of curing methods and heavy crude oil contamination on the mechanical properties of cement mortar. Mortar samples with different amounts of heavy crude oil (0%, 2%, and 10%) were cured using air, water, and sealed plastic. Water curing attained the highest compressive strength across different pollution levels by maintaining moisture for complete hydration. In contrast, air curing resulted in the lowest strength, especially for uncontaminated and 2% oil samples, due to rapid drying that limited hydration and increased porosity. Curing techniques did not affect the strength of samples with 10% heavy crude oil, perhaps due to oil saturation impeding hydration. Increased oil contamination, particularly with heavy crude, significantly enhanced porosity and reduced compressive strength. The high viscosity and complex molecular structure of heavy crude oil form a dense coating around cement particles, hindering hydration and undermining the integrity of the cement matrix. The findings suggest that selecting an appropriate curing procedure for low-level crude oil may facilitate repurposing materials contaminated with heavy crude oil as sustainable, cost-effective alternatives for specific civil engineering applications, offering a viable option for oil-contaminated sand.

Enhancing Cementitious Materials: A Detailed Review of Bentonite’s Role in Optimizing Concrete Performance

Zakaria Mekhnache — 2024-12-31

Cement manufacturing significantly impacts global CO₂ emissions, contributing around 8% due to its high energy demand and the calcination process in clinker production. To reduce this environmental impact, the industry is exploring sustainable alternatives by integrating supplementary cementitious materials (SCMs), which enhance cement properties and lower its carbon footprint, aligning with sustainable construction goals. One such material is bentonite, a naturally occurring clay with high plasticity and excellent water retention properties. When added to cement mixtures, bentonite improves essential properties like decreasing permeability, enhancing workability, and boosting chemical resistance. Its pozzolanic activity aids in long-term strength development, making it valuable for standard and specialized applications, including geotechnical engineering and waste containment. Bentonite supports environmental sustainability by reducing cement demand thus lowering CO₂ emissions and by increasing durability, which extends the lifespan of structures and cuts down on maintenance costs. This discussion will explore the various environmental and mechanical benefits of bentonite as a sustainable additive in cementitious systems and highlight studies that have demonstrated its effectiveness in promoting more eco-friendly construction practices.

Analyse the effect of carbon fiber reinforced polymer (CFRP) strengthening of beams using ANSYS

Sabiha Barour — 2024-12-31

This paper presents a nonlinear finite element model analysis to effect of carbon fiber reinforced polymer (CFRP) strengthening of beams using ANSYS, Finite element software ANSYS 12.0 has been used for modeling the beams by conducting nonlinear static analysis. The SOLID 65 and SHELL 181, LINK180 elements have been used to, respectively; model the 3D concrete beams and the composite layer, steel rebars. The results of the finite element were compared with the experimental data The results showed that the general behavior of the finite element models represented by the load-deflection curves shows good agreement with the test data from the previous researches.

Enhancing Compressed Earth Block Performance: Effects of Gelatinized Starch and Fiber Reinforcement on Mechanical Properties

Gabo Cyprien Bailly — 2024-12-31

This study investigates the impact of starch stabilization and fiber reinforcement on the mechanical properties of Compressed Earth Blocks (CEBs). Various stabilization methods were tested to enhance the mechanical performance of CEBs, with a focus on starch as a natural binder and the incorporation of hemp as natural fibers. The research findings indicate that while starch slightly reduced internal cohesion by 13%, the addition of fibers alone significantly improved compression resistance by increasing strength by a factor of 3.57. When combined with starch, the effectiveness of fibers on compression resistance slightly decreased to a factor of 3.21. Cement stabilization, though providing the highest strength with a factor of 7, poses greater environmental challenges due to its high energy consumption and carbon emissions. In contrast, starch and natural fibers offer promising, eco-friendly alternatives that enhance CEB performance while reducing environmental impact. This study highlights the potential for integrating sustainable materials into construction practices to meet both structural and environmental objectives.

A Reliability-Based Design of Africa-Birch Timber-Reinforced Concrete Beams

Alhassan Aliyu Abdulrazaq — 2024-12-31

This study investigates the reliability-based design of African-Birch (AB) timber-reinforced concrete beams. This study investigated Some of the physical and engineering properties of the constituent materials for the reinforced concrete beams were tested and preparing the reinforcement in four different composition and configurations (steel-steel, Steel- AB, AB-Steel, and AB-AB) of the beams were prepared, cast and cured for varying durations (3, 7, 14, 21, and 28 days), and the concrete was tested for its flexural strength and deflection and consequently reliability analysis (in terms of flexural strength and deflection) of all the beam configurations using First Order Reliability Analysis-5 (FORM5) to assess the beam performance was carried out. The flexural strength and deflection analysis reveals Steel-AB outperforming other sections and was found to be optimal under various loading conditions. For flexure, Steel-AB achieved a safety index (β) of 1.98 and probability of failure (Pf) of 0.0238 at a span length of 10,000mm and effective depth of 400mm. Similarly, for deflection, Steel-AB demonstrated a safety index (β) of 1.786 and probability of failure (Pf) of 0.037 at a span length of 2500mm. This study demonstrates that African-birch timber is a viable and sustainable alternative to traditional steel reinforcement for structural applications, particularly for medium span and depth beam-configurations.

Structural Performance of Reinforced Concrete Beams with Steel Fibres as Secondary Reinforcement: Experimental and Pre-peak Numerical Modelling

Hadjer Belkadi — 2024-12-31

This research consists of an experimental and a numerical investigation into improving the structural performance of reinforced concrete (RC) beams by incorporating hooked-end steel fibres. Experimentally, steel fibres were added to the concrete matrix of 80 mm × 180 mm × 1500 mm RC beams with fibre contents of 0%, 0.5%, and 1%, without replacing traditional reinforcement bars. Each beam underwent a four-point flexural test using a hydraulic press under static loading to evaluate the influence of fibres on flexural behaviour. The numerical analysis aimed to model the macro-scale flexural behaviour of RC beams using a 3D finite element approach in ABAQUS. Challenges in modelling steel fibres include their discrete nature and computational demands due to intricate meshing and convergence issues. The Simplified Concrete Damaged Plasticity Model was used to characterize the compressive and tensile behaviours of plain and steel fibre reinforced concretes. Nonlinear finite element analysis was performed to predict pre-peak load versus mid-span deflection and crack propagation. The model, which does not explicitly simulate steel fibres, was validated against experimental data, showing strong agreement and confirming its effectiveness in capturing the flexural behaviour of steel fibre reinforced concrete beams. Experiments Results showed that steel fibres enhance the flexural performance. Beams with steel fibres exhibited higher first crack loads, ultimate loads, flexural strengths, and toughness. Additionally, the fibres increased crack numbers, reduced crack spacing and length, and improved post-cracking behaviour. The simulation results were subsequently validated against experimental data. The results of the numerical finite element analysis were in good agreement with those of the experiments.

Producing 100+ MPa Field Concrete in Developing Countries: Requirements and Challenges

Youssef ElHawary — 2024-12-31

Over the past three decades, there has been a paradigm shift in the concrete industry in which high strength and high performance concrete became more widely in use. However, producing ultra-high strength concrete surpassing 100 MPa compressive strength in the field remains a challenging task. This is primarily due to the various factors involved in such concrete and its sensitivity to many of these factors. This study aims at producing field concrete surpassing 100 MPa compressive strength using readily available materials worldwide. The study also addresses the requirements and challenges of 100+ MPa concrete in the field in order to possess similar properties to conjugate mixtures produced in the laboratory having same mix proportions. Concrete mixtures were prepared with different water-to-cement ratios and incorporated variety of chemical and mineral admixtures. Tests included fresh concrete, self-consolidation as well as hardened concrete properties in order to determine the properties of the concrete produced. The impact of other vital factors such as mixing process, ambient temperature, curing process and pumping are addressed taking field conditions into consideration. Several field visits were conducted to monitor field concrete that was produced using the designated mixtures. The study herein revealed that reaching 100 plus MPa concrete is doable using variety of readily-available constituents and mix proportion. However, the study pinpoints the importance of other crucial factors and field practices. Recommendations are provided to concrete users and practitioners to exercise better quality control and ensure high rate of success in producing ultra-high strength concrete in the field.

Management and quality control of construction materials standards, techniques, and challenges

Severin Jean Maixent Loubouth — 2024-12-31

Construction materials are crucial for the safety and longevity of structures, as they must withstand environmental conditions and be durable. Adherence to stringent standards and regulations is essential for materials like concrete, steel, wood, bricks, and composites. Common defects include manufacturing flaws, storage issues, non-compliance with standards, and variability in quality. To minimize quality problems, rigorous control techniques like material testing, visual inspections, performance testing, and certifications are applied. Proper finishing enhances aesthetics, durability, and performance, while surface preparation, installation, and maintenance are critical for plumbing and electrical systems.