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Concrete is classified as a multi-composite material comprising three phases: coarse aggregate, mortar, and interfacial transition zone (ITZ). Fine and coarse aggregates occupy approximately 70–85% by volume, of which coarse aggregate typically constitutes more than two-thirds of the total quantity of aggregate by volume. The current study investigates the concrete performance produced using various recycled construction and by-product industrial waste coarse aggregates. Six types of coarse aggregates: manufactured limestone, quartzite, natural scoria, by-product industrial waste aggregate, and two sources of recycled concrete aggregates with densities ranging from 860 to 2300 kg/m3 and with different strength properties were studied. To determine the coarse aggregate contribution to the overall concrete performance, lean and rich concrete mixtures (Mix 1 and Mix 2) were used. Mix 1 (lean mixture) consisted of a ratio of water to cement (w/c) of 0.5 and cement content of 300 kg/m3, whereas a higher quantity of cement of 500 kg/m3 and a lower w/c ratio of 0.3 were used for Mix 2 (rich mixture). The results showed that while the compressive strength for different aggregate types in Mix 1 was comparable, the contribution of aggregate to concrete performance was very significant for Mix 2. Heavyweight aggregate produced the highest strength, while the lightweight and recycled aggregates resulted in lower mechanical properties compared to normal weight aggregates. The modulus of elasticity was also substantially affected by the coarse aggregate characteristics and even for Mix 1. The ACI 363R-92 and CSA A23.3-04 appeared to have the best model for predicting the modulus of elasticity, followed by the ACI-318-19 (density-based formula) and AS-3600-09. The density of coarse aggregate, and hence concrete, greatly influenced the mechanical properties of concrete. The water absorption percentage for the concrete produced from various types of aggregates was found to be higher for the aggregates of higher absorption capacity.

Purpose Building information modelling (BIM) has transformed the traditional practices of the Architecture, Engineering and Construction (AEC) industry. BIM creates a collaborative digital representation of built environment data. Competitive advantage can be achieved with collaborative project delivery and rich information modelling. Despite the abundant benefits, BIM’s adoption in the AEC is susceptible to confrontation. A substantial impediment to BIM adoption often cited is data interoperability. Other facets of interoperability got limited attention. Other academic areas, including information systems, discuss the interoperability construct ahead of data interoperability. These interoperability factors have yet to be surveyed in the AEC industry. This study aims to investigate the effect of interoperability factors on BIM adoption and develop a comprehensive BIM adoption model. Design/methodology/approach The theoretical foundations of the proposed model are based on the European interoperability framework (EIF) and technology, organization, environment framework (TOE). Quantitative data collection from construction firms is gathered. The model has been thoroughly examined and validated using partial least squares structural equation modelling in SmartPLS software. Findings The study’s findings indicate that relative advantage, top management support, government support, organizational readiness and regulation support are determinants of BIM adoption. Financial constraints, complexity, lack of technical interoperability, semantic interoperability, organizational interoperability and uncertainty are barriers to BIM adoption. However, compatibility, competitive pressure and legal interoperability do not affect BIM adoption. Practical implications Finally, this study provides recommendations containing the essential technological, organizational, environmental and interoperability factors that AEC stakeholders can address to enhance BIM adoption. Originality/value To the best of the authors’ knowledge, this paper is one of the first studies to combine TOE and EIF in a single research model. This research provides empirical evidence for using the proposed model as a guide to promoting BIM adoption. As a result, the highlighted determinants can assist organizations in developing and executing successful policies that support BIM adoption in the AEC industry.

This study evaluates the structural safety of composite RC wall systems, which consist of outer and inner RC walls with either an empty or a filled gap, against projectile impacts. The system is considered to have failed if its ballistic limit falls below the projectile’s striking velocity. To determine this limit, the wall system is transformed into an equivalent monolithic wall of the same total reinforcement and perforation energy. A modified UKAEA formula was employed to estimate this limit. To perform the reliability assessment, as the experiments were limited, over one million composite walls were simulated, and the probability of failure and reliability were estimated. Results show that, by leaving the gap unfilled between equally thick inner and outer walls, safety improves by 49.2% compared to a monolithic wall; the safety increases further to 68.2% and 68.9% by filling the gap with sand and recycled concrete aggregate, respectively. Greater gains occur with unequal wall thicknesses: 62% (no fill), 95% (sand), and 96% (recycled aggregate). Parametric analysis demonstrated the influence of filling density, gap thickness, and wall thickness ratios on system reliability. Overall, the findings confirm the superior protective performance and higher safety of composite wall systems compared to monolithic walls.

Fiber-reinforced polymer (FRP) composites have become a popular solution for upgrading reinforced concrete (RC) structures due to their corrosion resistance, high strength-to-weight ratio, and speed of implementation. However, their organic resin binder has issues, including temperature sensitivity, poor performance in moist conditions, a high cost, and potential health risks. Additionally, reversing FRP repair can be difficult and may damage the original structure, posing a significant reversibility issue. A promising alternative to FRP is the fiber-reinforced cementitious matrix (FRCM), which replaces the organic resin with an inorganic cementitious mortar. This new class of composite uses a breathable textile instead of the tightly packed fibers in FRP. The present article provides a comprehensive assessment of the two composites (FRP and FRCM) used for the retrofitting of RC compression members, with the purpose of identifying existing knowledge gaps and outlining future research objectives. The materials used in different strengthening approaches using both FRP and FRCM have been identified, and their stress–strain characteristics under tensile load have been outlined. The study also explores techniques of implementation using the two materials. This study presents available studies comparing the utilization of FRCM composites with FRP for the axial retrofitting of RC compression members in both ambient and high-temperature conditions.

This study investigates an innovative and sustainable hybrid approach combining enzyme-induced carbonate precipitation (EICP) with inclined micropile reinforcement systems for improving the soil bearing capacity of existing footings. The research evaluated two distinct EICP implementation methods across eleven experimental configurations, including three micropile inclination angles (90°, 105°, and 120°) for improving the bearing capacity of a square footing. The first method (method M1) involved injecting 150 mL of EICP solution through each of the eight perforated micropiles with a 21-day curing period, while the second method (method M2) employed staged injections around the footing totaling 1200 mL over two days with a 21–22-day curing period. Results demonstrated that the micropile-confined system combined with the EICP treatment significantly enhanced bearing capacity, with effectiveness increasing proportionally to pile inclination angles. While the EICP injection method M1 caused a 32% to 83% increase, method M2 exhibited 66% to 125% enhancement in bearing capacity for different micropile inclinations. Based on experimental validation, an analytical procedure was developed for predicting the bearing capacity of footings. This hybrid technique not only ensures structural effectiveness but also represents a sustainable, eco-friendly alternative to conventional ground improvement methods by reducing reliance on energy-intensive or chemically hazardous processes.

Reinforced concrete (RC) non-seismic frames in Middle Eastern multistory buildings often have beam–column connections with discontinuous bottom reinforcement, heightening the risk of progressive collapse if an outer column fails. This study aimed to reduce the potential for progressive collapse when a column is lost by investigating the use of bolted steel plates to enhance the beam–column joints of such frames. In this regard, high-fidelity finite element (FE) analysis was carried out on ten half-scale, two-span, two-story RC frames to simulate the removal of a center column. The numerical analysis accounted for the nonlinear rate-dependent response of steel and concrete, as well as the bond-slip model at steel bars/concrete interaction. The analysis matrix had three unstrengthened specimens that served as references for comparison, in addition to seven assemblies, which were strengthened using bolted steel plates. In the upgraded assemblies, the studied variables were the grade of steel plate (three grades were examined) and the upgrading scheme (three different schemes were investigated). The performance of the specimens was evaluated by comparing their failure patterns and the characteristics of load versus displacement of the middle column during both flexural and catenary action phases. Based on this comparison, the most efficient strengthening method was suggested.

In RC (reinforced concrete) frame structures, wall-like columns are laid within the space occupied by masonry walls to maximize usable space and thus minimize the column projections into the usable area. These columns often require strengthening owing to various reasons, including increasing the number of stories, changes in building usage, and others. The use of a hybrid system comprising NSM (near-surface mounted) steel rebars combined with CFRP (carbon-fiber reinforced polymer) laminates may be considered a sound technique for strengthening such wall-like building columns. The prime aim of this study is to devise an efficient scheme using a hybrid NSM/CFRP system to strengthen existing RC wall-like columns. Six half-scale RC wall-like columns were prepared and tested under monotonic concentric axial compression. Two columns were unstrengthened to serve as control specimens (CW1 and CW2), and four specimens were strengthened using four different schemes (SW1, SW2, SW3, and SW4). As favored by architects, all strengthening schemes were designed so that the dimensions of the column cross-section were not increased. The effects of strengthening schemes on the enhancement of axial capacity, energy dissipated, and stiffness were evaluated to find the most efficient scheme. Among the four studied schemes, using vertical continuous NSM rebars in combination with the wrapping of the three CFRP layers onto the exterior column surface (in specimen SW2) was the most efficient as it enhanced the ultimate load capacity by 80%. Three-dimensional FE (finite element) analysis was also conducted to predict the response of test specimens. The test results matched well with the FE outputs, which justified the accuracy of the used constitutive models for concrete, steel rebars, and CFRP sheets.

In the Middle East, RC joist slab systems with wide beams are widely used for residential floors. However, when these beams support planted columns, excessive deflection beyond code limits is often observed, despite adequate flexural and shear design. This paper experimentally assesses, for the first time, the efficacy of using carbon-fiber-reinforced polymer (CFRP) sheets alone versus a novel hybrid system comprising CFRP sheets and CFRP/honeycomb plates in controlling deflection in RC wide beams with planted columns. Four RC wide beam specimens at half-scale, each featuring a planted column, were tested to failure. Two control specimens, the first one was designed to reflect standard construction practices. It was sufficiently designed in flexure and shear, but its deflection exceeded code requirements. The second was designed to satisfy the code deflection requirements. The remaining specimens were strengthened using two different techniques: one with externally bonded CFRP sheets and the other with the hybrid system. The findings demonstrated a marked improvement in the flexural performance of the retrofitted wide beams, with peak load increases of 65–71%, stiffness gains of 63–67%, and reduced deflections meeting serviceability requirements (deflection at peak load was reduced by 45–48%). Furthermore, an analysis procedure was developed to estimate the flexural strength and deflection of these beams.

In recent years, the demand for high-strength concrete (HSC) for buildings has been steadily increasing. Continuous HSC deep beams are frequently employed in various structural applications, including high-rise buildings, bridges, and parking garages, due to their superior load capacity. Some cases require the addition of openings after the construction for passing utilities such as drainage and electricity. This study experimentally examines four two-span HSC deep beams: one control solid beam, one beam with circular openings, and two beams that utilized different strengthening schemes. The openings were asymmetrical circular openings, with one positioned in each span. This study sought to regain the full capacity of beams with openings by employing two types of strengthening schemes. The first one used bolted steel plates, while the second was a hybrid scheme that combined bolted steel plates with externally bonded fiber-reinforced polymer (FRP) sheets. Test findings demonstrated that both methods effectively restored the load capacity of the strengthened beams. The strengthened beam with steel plates achieved a load capacity of 125% compared to the solid beam. Likewise, the beam retrofitted with hybrid steel/FRP composites reached 117%. Additionally, the energy dissipation and ductility index of the strengthened beam with steel plates were 32% and 77%, respectively, compared to the strengthened beam with hybrid steel/FRP composites. The findings emphasize the effectiveness of the applied retrofitting techniques in restoring the lost capacity due to the cutting of post-construction openings in deep beams.