Bassam A. Tayeh’s research while affiliated with University of Waterloo and other places

This research examines the influence of blast furnace slag (BFS) on the physico-mechanical properties of compressed earth blocks (CEBs) stabilised with cement and/or lime. A three-factor mixture design is employed to assess the effects of BFS, cement and lime on key properties such as dry density, water content and compressive strength at 28 and 90 days. The study maintains a constant dune sand proportion with soil substitutions up to 20% (420 grams), while the BFS, lime and cement proportions vary with soil substitutions up to 15% (315 g). The findings indicate that mixtures with over 7.5% cement and equal proportions of lime and BFS, as well as a ternary mixture of 10% cement, 2.5% lime and 2.5% BFS, deliver superior strength. Notably, the optimal compressive strength with a high desirability score of 0.93 is achieved using around 14% cement and 1% lime. Proctor curve analysis shows that BFS-cement-lime substitution reduces water content and increases dry density. Statistical analysis confirms the model's robustness in predicting compressive strength, supported by high F-values and low probabilities, and highlights its effectiveness in guiding design decisions. Additionally, the study's evaluation of rupture types offers further insights into material strength and validates adherence to testing standards.

Because cement is the primary component of concrete, the production of concrete results in a significant amount of carbon dioxide emissions. Concrete, thus, has an impact on the environment. Concrete may undergo a change in its nanostructure if it contains even a trace number of nanoparticles (NPs). Constructions made of concrete would be more long-lasting and would have a smaller impact on the environment. Researchers know very little about NPs before they are utilized, and the findings of their investigations have been inconsistent despite the fact that a large number of studies have been conducted. In contrast to the inclusion of metals, NPs, particularly nano-silica (NS) and nano-ferrite (NF), have garnered a lot of attention. Due to the fact that NPs perform more effectively in concrete than metal complexes. To evaluate bids, it is essential to provide background information on the most common methods for the manufacture and fabrication of nanomaterials. The parameters that influence the behavior of NPs in cement-based materials have also been the subject of extensive research. There are also processes for mixing and dispersion, as well as super-plasticizers and nanoparticle agglomeration. The mechanical properties of mixtures containing NPs are also assessed. This encompasses modulus of elasticity, splitting tensile strength, compressive strength, and flexural strength. An assessment is conducted to ascertain the penetration of chloride ions in water, permeability, and fire resistance. This study examines various methods for dispersing NS and NF particles to reduce the probability of agglomeration. The investigation also examines how the buildup of NS particles affects the properties of nano-modified concrete. The study revealed that augmenting the nanoparticle substitution by 3–5% can enhance compressive strength. The hydration process is enhanced by extensively disseminated NPs, which also provide a denser microstructure. The incorporation of NF into concrete enhances tensile strength, permeability, and durability, even at concentrations as minimal as 2%. The graphical abstract encapsulates the research conducted in this article.

Earthquake damage in regions with high seismic risk highlights the need for. measures to improve the earthquake performance of existing structures. One such measure is strengthening these structures to bring them up to the desired performance levels. In this study, the damage to reinforced concrete (RC) buildings was examined in light of the February 6, 2023, Kahramanmaraş (Türkiye) earthquakes to identify the reinforcement needs of RC structures. Numerical analyses were conducted, considering two main factors affecting the shear force capacity in RC columns: low-strength concrete and inadequate transverse reinforcement. The columns were strengthened using four different types of fibre-reinforced polymer (FRP) wrapping, applied to all columns where the shear force was exceeded. The results for the reference building and the four different wrapping methods were compared, and suggestions were made. It was found that all four wrapping methods significantly increased the shear strength capacities of the columns without causing any failure.

In the current study, the impact of utilizing granite and marble construction waste powders as replacements (1%–9%) for cement on concrete compressive strength was investigated. In the second stage of the experimental program, combined mixtures were designed to evaluate their response to high temperatures using various machine learning (ML) techniques. Models employing water cycle algorithm (WCA) and genetic algorithms (GA) were developed based on 288 experimental results, featuring input variables such as temperature, exposure time, waste powder type, and cement replacement ratio, with residual compressive strength (RCS) as the sole output. Artificial neural networks (ANN), fuzzy logic (FL), and multiple linear regression (MLR) models were also developed for comparison. Optimal performance, with a 22% increase in compressive strength at 28 days, was observed by replacing 9% of cement with waste granite powder (WGP). At high temperatures, the best performance occurred with 9% WGP + 5% waste marble powder (WMP), resulting in a 59.6% increase in RCS value after exposure to 800 C for 2 h. The predictive WCA model outperformed GA and MLR, closely aligning with ANN and FL models, with a mean absolute error of 3.96 kg/cm2. Additionally, nonlinear prediction equations of RCS with high regression values were successfully developed using WCA and GA. Furthermore, sensitivity analyses were conducted using the weights of the hidden layers of the idealized neural networks and revealed that the RCS value exhibits high sensitivity to temperature variations. Exposure time had the second-highest impact on RCS value, followed by the WGP ratio, and then the WMP ratio.

Global warming and resource depletion necessitate sustainable concrete production. This study examines the use of waste construction powders as partial cement replacements (up to 9 %) in concrete. The waste powders studied were granite (WGP), marble (WMP), granodiorite (WGDP), and ceramic (WCP). The effects of these waste powders on the mechanical, microstructural properties, and radiation shielding capabilities of ordinary concrete were investigated. The concrete mixture that demonstrated the greatest compressive strength, a 25.6% increase after 28 days, contained a 9% WGP replacement ratio. The optimal tensile strength after 28 days, showing a 19.7% improvement, was achieved with a 7% WCP replacement rate. The concrete specimens with the highest compressive strength (containing waste powders) demonstrated enhanced radiation shielding capabilities compared to the control mix. For WCP concrete mix, the CMix linear attenuation values were the highest due to its high density and greatest Ti/Fe content. Fast-neutron removal worked best with the 9 % WGP.

Incorporating zinc oxide nanoparticles (N-ZnO) is possible in lightweight foamed concrete (LWFC) construction. This paves the way for studies of the thermal, mechanical, pore structure, and other aspects of the LWFC that make use of the N-ZnO. For this purpose, six LWFC mixtures were formulated as cement additives ranging from 0 to 1% N-ZnO. Fresh state attributes included setting time, workability, plastic, and dry density. The transport parameters, specifically sorptivity, water absorption, and intrinsic permeability, were all analyzed. Compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, and dry shrinkage were among the mechanical parameters investigated. Thermal properties, pore organisation, SEM analysis, and dispersion were also studied. N-ZnO has been shown to minimise slump flow diameter, initial, and final setting times while increasing LWFC dry density in laboratory trials. By increasing N-ZnO to 0.6%, transport, mechanical, and pore characteristics were enhanced. After 28 days, the LWFC with 0.6% N-ZnO had 70% higher compressive strength, 82% higher flexural strength, and 84% higher splitting tensile strength than the control mix. In terms of SEM and pore dispersion, N-ZnO-based concrete was the superior pore filler, accounting for up to 0.6% more volume. All density, thermal conductivity, and diffusion conductivity improved for all N-ZnO-based specimens, especially at 0.6% N-ZnO.

Eco-friendly foamed concretes (FC) were produced in the present study using two types of industrial by-products widely available namely fly ash (25 and 50 % by weight) and gypsum board (5, 10, 15, 20 and 25 % by weight) as partial cement substitution. This study employs these waste materials, aiming to reduce the environmental impact and manufacture cost and improving the FCs properties. Effects of FA and WGB on the FC properties were systematically investigated by diverse tests and characterization techniques. Setting time, slump flow test and fresh density were carried out on fresh concretes, while compressive and flexural strength, splitting tensile strength, modulus elastic, porosity, chloride test penetration were performed on hardened FCs (7, 14, 28, 56 and 180 days). The results revealed that incorporating the waste gypsum board (WGB) up to 25 % prolonged the setting times and increased the slump flow of FCs blended without (FA0, reference) and with 25 and 50 % of fly ash (FA25 and FA50). FA25 and FA50 developed high performance in terms of compressive and flexural strength, elastic modulus, low porosity and densified structure than FA0. The high mechanical properties of FA25 (8.30 MPa) and FA50 (6.20 MPa) achieved on specimens at 180 days tend to decline over 10 % of WGB sug gesting the presence of voids and large pores which weakened the strength development (4.50 and 3.12 MPa, respectively). The evaluation of the FC mixes using various methodologies has demonstrated that the optimal mix is achieved when WGB and FA are applied simultaneously. FA25 and FA50 well performed in well performed in rapid chloride permeability than reference FA0. The WGB industry would become more viable and have positive environmental effects if WGB and FA were used appropriately in place of cement. FCs containing FA and WGB with controlled density and proper strength can be used in prefabricated buildings and energy-saving insulation components. For large application the obtained results may be helpful in assessing the combined effect FA-WGB additives on the fresh and hardened properties and durability of FCs made with these waste materials.