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This investigation elucidates the development of an innovative, sustainable binder derived from calcium carbide residue and silica fume, aimed at enhancing soft clay stabilization with minimal environmental impact. Various mixtures were examined, focusing on the CaO to SiO2 molar ratio (Ca/Si), which varied from 1.85 to 0.65. Comprehensive analyses of the raw materials and pastes, including chemical composition, phase evolution, and microstructure, were conducted using techniques like Energy dispersive X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Results indicate a significant impact of raw material fractions on the compressive strength and cementitious properties. The mixture with a Ca/Si of 1.55 demonstrated the highest long-term strength, attributed to increased C–S–H content. A mixture of 30 wt% calcium carbide residue and silica fume was found to improve the unconfined compressive strength of soft Bangkok clay by 84% compared to 10 wt% ordinary Portland cement, demonstrating its efficacy and potential for widespread application in green construction initiatives. This research not only promotes the recycling of industrial by-products, reducing environmental impact, but also represents a significant advancement in sustainable construction materials.

Abstract The incorporation of waste materials into cementitious binders serves as a strategy to diminish waste volume and lower carbon emissions. This study presents an in-depth evaluation of calcium carbide residue and coal fly ash as alternative binders. The assessment of raw materials emphasized their chemical composition and potential for pozzolanic reactions. Based on these factors, the optimal ratio of Ca/(SiO2 + Al2O3) in the raw materials was determined to be 1.5. Therefore, this study was designed to vary the raw material composition with a CaO/(SiO2 + Al2O3) ratio ranging from 1.7 to 0.9. Upon investigating the effect of the raw material proportion on the compressive strength of pastes and mortars, the composition yielding the highest compressive strength was selected for its potential application as a stabilizer for loess soil. A mixture of calcium carbide residue and coal fly ash with a Ca/(SiO2 + Al2O3) ratio of 1.5 resulted in the highest compressive strength at long curing periods in both pastes and mortars. Mineralogical and microstructural analyses revealed several products, beyond those formed from the pozzolanic reactions, that occurred and enhanced the compressive strength of samples. The highest performing mixture of carbide residue and coal fly ash was then used to stabilize loess soil at 10–25 wt%. The unconfined compressive strength, along with mass and strength loss due to wetting and drying cycles, was also studied. It was observed that the unconfined compressive strength of the stabilized soils remained consistent after six wet-dry cycles but decreased after twelve cycles due to microcracks. The findings suggest that carefully designed mixtures based on the chemical interactions of calcium carbide residue and coal fly ash can offer a sustainable, efficient approach for soil stabilization, potentially revolutionizing construction practices.

This study presents an innovative approach to enhance the flexural capacity of cement-clay interlocking (CCI) brick walls using ferrocement jackets with an expanded wire mesh. The investigation involved 15 CCI brick walls subjected to flexural load testing, exploring various mesh sizes and anchor configurations on single and dual sides. The results revealed that while the primary failure mode involved dry joint opening and subsequent ferrocement debonding in the strengthened walls, effective anchorage mechanisms delayed dry joint opening until debonding occurred. The reinforced walls exhibited improved peak load capacity, notably in dual-sided reinforcement cases. With plastering on both sides and supplemented with anchors, an improvement of up to 221% in flexural capacity was obtained. The study emphasizes the influence of wire mesh size on anchorage effectiveness and its correlation with debonding susceptibility. Additionally, the moment-curvature analysis demonstrated resilient, ductile responses in load-bearing characteristics, with occasional abrupt declines due to ferrocement jacket debonding. Unlike control walls, the strengthened walls exhibited strains exceeding yield thresholds, indicating enhanced structural performance.

The utilization of recycled waste in the production of new concrete raises significant concerns regarding the quality of the resulting concrete. One prominent drawback of recycled aggregate concrete (RAC) is its inferior mechanical properties compared to natural aggregate concrete. In this study, we examine the impact of hemp fiber rope (HFR) confinement on improving the compressive stress-strain behavior of RAC, specifically using recycled brick aggregates from fired-clay solid bricks (RAC-FCSB) as a partial substitute for natural coarse aggregates. Furthermore, we explore and compare the effectiveness of HFR confinement in the form of strips versus fully wrapped confinement. To conduct the experiments, a comprehensive framework was developed, involving a total of 32 cylindrical specimens. The parameters of interest included the configuration of HFR confinement (strips or full wrapping), the number of HFR layers, and the inherent strength of the concrete. The results indicate that HFR strips can significantly enhance the compressive stress-strain response. However, their performance falls short when compared to the fully wrapped HFR confinement. Nonetheless, HFR strips were able to enhance the peak compressive stress and strain of RAC-FCSB up to 204% and 190%, respectively. The second part of the study investigated the performance of existing models of HFR confinement in predicting the peak compressive stress and strain of RAC-FCSB. The deficiencies in existing models were highlighted, and new models based on non-linear regression analysis were proposed to accurately predict the peak compressive stress and strain of HFR-confined RAC-FCSB.

The low cost of cement-clay interlocking (CCI) bricks is an attractive feature, resulting in a wide utilization of CCI bricks in the construction of masonry walls. Despite this, an experimental database on the performance of CCI brick walls is scarce. This study tested ten large masonry walls constructed with CCI bricks in a running bond pattern. Two types of CCI bricks were used to assess the effect of chemical position on the diagonal compressive capacity of walls. Further, different grouts and steel bars were used within the openings in CCI bricks. A combination of grout and steel bars resulted in the optimal improvement of the diagonal compressive strength, whereas up to 110% higher improvement in the diagonal compressive strength was achieved by doubling the compressive strength of grout. Interestingly, the type of bricks did not influence the improvement in the diagonal compressive capacity of CCI brick masonry walls. A regression-based equation was proposed to predict the diagonal compressive capacity of CCI brick walls by including the yield strength of steel bars, the compressive strength of grout, and the diagonal compressive strength of ungrouted walls as explanatory variables. The predicted capacities of CCI brick walls were found to be in close agreement with experimental results.

Each year, an enormous amount of construction waste is produced worldwide. The reuse of construction waste in construction works is a sustainable solution. The present research work utilized recycled brick aggregates in the production of concrete. The resulting concrete exhibited substandard splitting tensile, flexural, and compressive properties. Steel fibers were used to improve these substandard properties of recycled brick aggregate concrete. The volume fractions of 1%, 2%, and 3% for steel fibers were mixed in concrete, whereas recycled brick aggregates were obtained from solid fired-clay bricks, hollow fired-clay bricks, and cement–clay interlocking bricks. The compressive strength was enhanced by up to 35.53% and 66.67% for natural and recycled brick aggregate concrete, respectively. Strengthened flexural specimens demonstrated up to 8765.69% increase in the energy dissipation. Specimens strengthened with steel fibers showed substantially improved splitting tensile, flexural, and compressive responses. Separate equations were proposed to predict the peak compressive strength, strain at peak compressive strength, elastic modulus, and post-peak modulus of recycled brick aggregate concrete. The proposed regression equations were utilized in combination with an existing compressive stress–strain model. A close agreement was observed between experimental and predicted compressive stress–strain curves of recycled brick aggregate concrete.

Excessive volumetric changes associated with shrinkage and non-uniform moisture and heat distribution along long-span girders induce unwanted curvatures. This study aims at investigating both short- and long-term measurements of various quantities involving midspan deflections, tendon strains, longitudinal steel bar strains, concrete strains, and thermal changes in precast-post-tensioned (PCPT) girders. A total of 2 PCPT girders were cast in this study with symmetrical structural and geometrical details. Post-tensioning of the first and second girders was performed on the 28th and 120th days of their casting, respectively. Long-term measurement was performed on the first girder. It was observed that all measured parameters increased swiftly during post-tensioning. During the initial 30 days after post-tensioning, a gradual increase in all parameters was observed, whereas all measured parameters exhibited negligible increase beyond that. A Finite Element Model was generated using ATENA to estimate short-term deflections of PCPT girders during post-tensioning. In general, a good agreement between experimental and analytical midspan deflections was observed.

This study investigated the influence of CFRP composite wrapping techniques on the load–deflection and strain relationships of non-prismatic RC beams. A total of twelve non-prismatic beams with and without openings were tested in the present study. The length of the non-prismatic section was also varied to assess the effect on the behavior and load capacity of non-prismatic beams. The strengthening of beams was performed by using carbon fiber-reinforced polymer (CFRP) composites in the form of individual strips or full wraps. The linear variable differential transducers and strain gauges were installed at the steel bars to observe the load–deflection and strain responses of non-prismatic RC beams, respectively. The cracking behavior of unstrengthened beams was accompanied by excessive flexural and shear cracks. The influence of CFRP strips and full wraps was primarily observed in solid section beams without shear cracks, resulting in enhanced performance. In contrast, hollow section strengthened beams exhibited minor shear cracks alongside the primary flexural cracks within the constant moment region. The absence of shear cracks was reflected in the load–deflection curves of strengthened beams, which demonstrated a ductile behavior. The strengthened beams demonstrated 40% to 70% higher peak loads than control beams, whereas the ultimate deflection was increased up to 524.87% compared to that of the control beams. The improvement in the peak load was more prominent as the length of the non-prismatic section increased. A better improvement in ductility was achieved for the case of CFRP strips in the case of short non-prismatic lengths, whereas the efficiency of CFRP strips was reduced as the length of the non-prismatic section increased. Moreover, the load–strain capacity of CFRP-strengthened non-prismatic RC beams was higher than the control beams.

Blended fibres are being utilized in ordinary Portland cement-based materials (CBMs). The inclusion of blended fibre (a mix of several fibre types) may help CBMs perform better under fire. Fibre factor (F.F) and mechanical characteristics of blended fibre-reinforced CBMs are investigated in this research under various temperature conditions. In addition to mechanical characteristics, empirical models for strength properties in response to temperature and F.F. are established. The addition of calcite powder to blended fibres in CBMs increased mechanical strength across the board at all temperatures. However, increasing the temperature from 20 °C to 750 °C resulted in 75%, 79%, and 84% reductions in compression, split tension, and flexure strength of blended fibre-reinforced CBMs, respectively. For compression, split tension, and flexure strength, empirical models with R2 values of 0.98, 0.92, and 0.93 were constructed, with fibre factor and temperature as the major affecting variables. Experimental data for blended fibre-reinforced CBMs revealed that empirical models predicted superior outcomes, which was brought into existence.

Re-use of recycled aggregates in concrete has become a very sustainable solution owing to its environment-friendly and cost-effective nature. Clay bricks are most widely used in construction all over the world. Subsequently, waste generated from the demolition of clay-brick structures is most troublesome. Inherent porosity of bricks compromises the compressive strength of concrete with clay brick aggregates (C-CBA) that has rendered its use in structural concrete for quite some time. With some external clamping pressures, this deficiency can be countered. This study presents an experimental investigation into the use of steel clamps as a strengthening material for C-CBA. Steel clamps are cost-effective, readily available, and very easy to use. C-CBA were tested in two groups depending upon compressive strength: 15 & 35 MPa. Further, 3, 5, and 11 steel clamps were used in each group. Results suggested that steel clamps can effectively be used in enhancing the compressive strength of C-CBA to a level that is acceptable to be used in structural concrete. Increase in peak compressive strength of C-CBA was found to be proportional with the number of steel clamps employed. Three analytical concrete models were used to predict the compressive strength of C-CBA after strengthening. It was concluded that all three analytical models predicted well C-CBA compressive strength for 3-clamp specimens. However, their pre-diction accuracy was highly compromised as the number of steel clamps were increased.

Cement is the main component of concrete, a widely used building material. Cement production requires substantial energy, exhausts natural resources, and causes CO2 emissions. Efforts are being undertaken to develop a concrete binder instead of cement. Geopolymer composite (GPC) is developed as a potential new building material, offering a clean alternative for construction sustainability. This study accumulated extensive bibliometric data on GPC from the Scopus database and conducted a scientometric analysis employing an appropriate software. The leading sources of publications, highly used keywords in the published articles, writers and papers with the highest citations, and active regions were all identified in the scientometric analysis. Manual reviews are unable to deal with the vast bibliometric data effectively. Additionally, this study covers the most crucial research concerns and shortcomings in existing research about GPC adoption and application. Lastly, further research guidelines are suggested. The scientometric review will assist academics from various states to exchange innovative ideas and expertize, encourage collaborative research, and develop joint ventures.

Concrete is a widely used construction material, and cement is its main constituent. Production and utilization of cement severely affect the environment due to the emission of various gases. The application of geopolymer concrete plays a vital role in reducing this flaw. This study used supervised machine learning algorithms, decision tree (DT), bagging regressor (BR), and AdaBoost regressor (AR) to estimate the compressive strength of fly ash-based geopolymer concrete. The coefficient of determination (R2), mean absolute error, mean square error, and root mean square error were used to evaluate the model's performance. The model's performance was further confirmed using the k-fold cross-validation technique. Compared to the DT and AR model, the bagging model was more effective in predicting results, with an R2 value of 0.97. The lesser values of the errors (MAE, MSE, RMSE) and higher values of the R2 were the clear indications of the better performance of the model. Additionally, a sensitivity analysis was conducted to ascertain the degree of contribution of each parameter towards the prediction of the results. The application of machine learning techniques to predict concrete's mechanical properties will benefit the area of civil engineering by saving time, effort, and resources.

Masonry structures are used in many parts of the world because of their varying benefits of being low-cost, heat insulations, local availability, and skilled labor. Therefore, to investigate the compressive stress-strain behavior and detailed analysis and assessment of masonry structures made of CCI bricks is imperative. Axial compressive results of 10 hollow cement-clay interlocking (CCI) bricks made masonry walls are presented. 10 masonry walls were tested under concentric compressive load in 2 groups. Bricks of each group had different compressive strength. Five walls in each group comprised of 1 control wall (ungrouted), 1 wall grouted with Ordinary Portland Cement (OPC), 1 wall grouted with non-shrink (NS) cement, 1 wall grouted with OPC and strengthened by steel bars, and 1 wall grouted with NS and strengthened with steel bars. Among 5 walls in each group, control wall created the lower bound in terms of the peak load sustained. While the upper bound was created by the wall grouted with NS cement and further strengthened by steel bars. It was found that the addition of grout (irrespective of its type) significantly improved the peak compressive load. However, increase in peak load over that of the control wall was associated to the grout type. Walls grouted with NS cement attained higher peak loads as compared to those grouted with OPC. It was observed that the addition of cement grout does not guarantee a ductile post-peak behavior. Addition of steel bars not only increased the peak loads, but it also improved the post peak behavior. Accuracy of existing compressive load analytical models was assessed, and it was found that none of the analytical models considered were able to predict close approximations. A linearly regressed model is proposed to predict compressive strength of CCI brick masonry walls with good accuracy.

Many masonry structures are constructed with cement clay interlocking brick (CCIB) due to its added benefits. Recent research has demonstrated the vulnerability of brick masonry walls against seismic loading. Various strengthening materials and techniques are extensively used to improve the structural behavior of brick walls. Carbon fiber-reinforced polymer (CFRP) composites are the most popular strengthening material due to their advantages of easy application, lightweight qualities, and superior tensile strength. The current research work aimed to explore the cost-effective solutions and feasibility of CFRP composite-based strengthening techniques to improve the load-bearing capacity of CCIB walls. Various configurations and combinations of strengthening materials were investigated to customize the cost of repair and strengthening. The experimental results indicated that CFRP composites in combination with cement-sand (CS) mortar are an efficient strengthening material to enhance the strength and ultimate deflection of CCIB walls. The ultimate load-bearing capacity and axial deformation of the strengthened CCIB wall (using two layers of CFRP strips and CS mortar of 10 mm thickness) remained 171% and 190% larger than the unstrengthened CCIB wall. The conclusions of this study are expected to enhance the seismic performance of masonry buildings in developing countries. It should be noted that due to the reduced number of tested specimens, the results to be assumed as general considerations need a wider experimental campaign and a large numbers of tests for each strengthening typology.

Several recent earthquakes have indicated that the design and construction of bridges based on former seismic design provisions are susceptible to fatal collapse triggered by the failure of reinforced concrete columns. This paper incorporates an experimental investigation into the seismic response of nonductile bridge piers strengthened with low-cost glass fiber reinforced polymers (LC-GFRP). Three full-scale bridge piers were tested under lateral cyclic loading. A control bridge pier was tested in the as-built condition and the other two bridge piers were experimentally tested after strengthening them with LC-GFRP jacketing. The LC-GFRP strengthening was performed using two different configurations. The control bridge pier showed poor seismic response with the progress of significant cracks at very low drift levels. Test results indicated the efficiency of the tested strengthening configurations to improve the performance of the strengthened bridge piers including crack pattern, yield, and ultimate cyclic load capacities, ductility ratio, dissipated energy capacity, initial stiffness degradation, and fracture mode.

This paper presents a study of the combined effect of PVA (powder form) and fly ash on the mechanical properties of concrete. Three different parameters (PVA, fly ash, and different patterns of curing) were used. The Taguchi statistical method has been used to decrease the number of concrete specimens from 160 to 54. Different percentages of PVA (1% and 2%) with fly ash (10% and 20%) were used in 36 concrete samples. Afterward, all samples were cured in three different ways namely: Open air-dry curing, normal water curing, and temperature bath curing. Samples with 1% PVA and 10% Fly ash shows the highest compressive strength, tensile strength, and modulus of elasticity. The improvement in strength is due to the interaction of PVA and FA with cement, filling pores, and strengthening the bond between the cement. Furthermore, the samples kept in water curing exhibited the greatest strength among all types of curing.

The excessive production of construction waste is a significant concern as it requires proper disposal and may become economically unfeasible. Reusing construction waste in producing new concrete can substantially reduce the disposal requirements of construction waste. In addition, this results in a sustainable solution for the rapidly depleting natural resources of concrete. Pervious concrete may contain up to 80% coarse aggregates and could be an exceptional host for reusing construction waste. This study aimed to investigate the mechanical properties of pervious concrete constructed with natural and recycled aggregates. The substandard properties of recycled aggregates were improved by adding natural fibers from sackcloth. This study presents an experimental program on 45 samples of pervious concrete with air void ratios and the size of coarse aggregates as the parameters of interest. The compressive strength of the pervious concrete decreased by increasing the air void ratio regardless of the size of the aggregates. The type of aggregates did not influence the permeability of pervious concrete, and the maximum temperature in pervious concrete increased as the quantity of air void ratios increased. The decrease in compressive strength was 40–60% as the void ratio was increased from 10–30% for all types of concrete mixes, such as natural and recycled aggregates. The permeability of small-size aggregates with 10% designed air void ratios for natural and recycled aggregates with sackcloth was 0.705 cm/s.

Recently, hemp-fiber-reinforced polymer (HFRP) composites have been developed to enhance the strength and ductility of normal and lightweight aggregate concrete along with recycled brick aggregate concrete. In addition, both experimental and analytical investigations have been performed to assess the suitability of the existing strength and strain models. However, the theoretical and analytical expressions to predict the stress–strain curves of HFRP-confined concrete were not developed. Therefore, the main objective of this study was to develop analytical expressions to predict the stress–strain curves of HFRP-confined waste brick aggregate concrete. For this purpose, a new experimental framework was conducted to examine the effectiveness of HFRP in improving the mechanical properties of concrete constructed with recycled brick aggregates. Depending on the strength of the concrete, two groups were formed, i.e., Type-1 concrete and Type-2 concrete. A total of sixteen samples were tested. The ultimate compressive strength and strain significantly increased due to HFRP confinement. Improvements of up to 272% and 457% in the ultimate compressive strength and strain were observed due to hemp confinement, respectively. To predict the ultimate compressive strength and strain of HFRP-confined concrete, this study investigated several existing analytical stress–strain models. Some of the strength models resulted in close agreement with experimental results, but none of the models could accurately predict the ultimate confined strain. Nonlinear regression analysis was conducted to propose expressions to predict the ultimate compressive strength and strain of HFRP-confined concrete. The proposed expressions resulted in good agreement with experimental results. An analytical procedure was proposed to predict the stress–strain curves of hemp-confined concrete constructed by partial replacement of natural coarse aggregates by recycled fired-clay brick aggregates. A close agreement was found between the experimental and analytically predicted stress–strain curves.

The construction sector has a significant impact on the environment, contributing significantly to energy consumption, resource depletion, and CO2 emissions. This sector is currently shifting away from natural materials and cement in favor of alternative materials, thereby reducing environmental impact and promoting sustainability. Worldwide, enormous quantities of waste materials are generated. Most of these waste materials are hazardous, corrosive, flammable, chemically reactive, incendiary, and infectious and are typically disposed of in landfills, causing environmental pollution and posing health risks. As a result, incorporating waste materials into concrete would be a more prudent course of action. This study collected vast bibliometric data comprising journal articles and review articles from the Scopus database over the last two decades and conducted a scientometric review on waste material utilization in concrete. Scientometric analysis is used to determine the current state of research by analyzing available bibliometric data and identifying related publication areas, sources with the most publications, the most frequently occurring keywords, authors, and papers with the most citations, and states that have made the greatest contribution to the field of waste materials utilization in concrete. Moreover, the most active research areas are identified and discussed. Also, the sustainability aspects of recycling waste materials in concrete are discussed, and finally, future research is proposed. The scientometric review will enable scholars from diverse countries to exchange novel ideas and knowledge, foster research collaboration, and establish joint ventures.

Cement-based composites (CBCs) are the widely used construction materials, and cement is their main ingredient. The production of cement consumes a considerable amount of energy, releases a substantial quantity of CO2 to the environment, and causes depletion of natural resources. Thus, utilizing sugarcane bagasse ash (SBA) in CBCs in place of cement might be a sustainable approach. In this review, two approaches have been adopted, namely, scientometric analysis and a thorough manual review of the use of SBA in CBCs. A scientometric analysis can deal with huge bibliometric data without complications. This study retrieved journal articles and review articles on SBA utilization in CBCs available at the Scopus database from 2007 to 2021 and performed a scientometric analysis using a suitable software tool. The aim of the scientometric analysis was to ascertain the current state of research and to identify relevant publication fields, sources with the most publications, the most frequently used keywords, the most cited articles and authors, and the countries that have made the greatest contribution to the field of SBA utilization in CBCs. Additionally, the influence of SBA on the fresh and hardened properties as well as durability properties of CBCs are comprehensively discussed. It was found that the top publication source is construction and building materials with 36 publications, the author with most publications is Bahurudeen A with 14 articles, and the country having the highest contribution in the relevant field is India with 110 publications. Furthermore, the addition of SBA in CBCs as cement replacement was found to be beneficial in terms of sustainability aspects and performance of composites. This study also highlighted the limitations associated with SBA utilization in CBCs and reported recommendations for future studies.

To date a large number of studies have been carried out on the use of different materials such as concrete, steel, fiber reinforced polymer (FRP) composites, to enhance the strength and ductility of the reinforced concrete (RC) members. Among these materials, concrete and steel are heavy weight, whereas FRP are expensive along with skin problems during handling and installations. In this paper, the efficiency of natural sisal fiber reinforced polymer composites is evaluated on strength and ductility of RC members. The salient features of natural sisal FRPs are low density, higher toughness, acceptable strength properties, reduced irritation to the skin and respiratory system, biodegradable and sustainable since they are natural products. The objectives of this research were twofold. The first was to evaluate the compressive and flexural behavior of small-sized concrete specimens (cylinders and beams) strengthened with natural sisal FRPs, considering different resin matrices, FRP thickness and concrete strengths. Whereas, the second objective was to investigate the strengthening effect of natural sisal FRP strengthening on the flexural response of RC beams. Test results showed that externally bonded natural sisal FRPs are significantly effective to increase the strength and ductility of the concrete members. In general, the experimental results demonstrated a higher increase in the load carrying capacity when the thickness of the sisal FRPs was increased. However, RC beams strengthened by natural sisal FRP, may fail by de-bonding of FRP from the concrete surface. To avoid this failure, a new anchoring system has been proposed and tested to evaluate their performance in preventing the de-bonding of FRP from concrete surface. Based on experimental results, proposed anchoring system was found to be effective to prevent the delamination of natural sisal FRPs from concrete surface.

This study presented the results of an experimental program conducted on a newly proposed Full-scale Precast Post-tensioned Continuous (FPPC) girder for straddle monorail. The investigated FPPC girder represents the actual size, design and construction details for a newly designed monorail transit system (Yellow Line and Pink Line Monorail) in Bangkok, Thailand. The salient features of the newly proposed girder system include lightweight, low-cost, easy and fast construction. The newly proposed FPPC girder is mainly comprised of three reinforced concrete (RC) hollow haunched girders, four piers or supports, two pier segments, four wet joints, and four bearings at each support. The FPPC girder was constructed at the casting yard of Sino-Thai Engineering and Construction Public Company Limited (STECON), Thailand. The FPPC girder was tested under different loading conditions (such as service and ultimate loading conditions). Both service and ultimate loads were applied as two-point loadings. Service load in a monotonic manner was applied on the right exterior span (two-point), middle span (two-point), and on the left exterior span and middle span (four-point). Meanwhile, the ultimate load in a monotonic manner was applied only on the left exterior and middle span as a four-point loading scheme. The test results indicate that the behaviour of the FPPC girder under service load conditions is elastic. Further, cracking of the concrete was not observed at any location. The observed maximum deflections under service load conditions were less than the permissible limits at all locations. Further, the maximum ultimate load-carrying capacity was observed to be much greater than the design load under ultimate loading conditions. This is an indication that the design details and construction procedure of FPPC girder are appropriate and further that this system could be used effectively to construct straddle monorail transit systems. Finite element analysis of FPPC monorail bridge girder was also performed by using a computer program ATENA which is a computational tool for nonlinear engineering analysis of bridges and culverts. The finite element analysis results indicate that the computer program ATENA is well capable to predict the ultimate load carrying capacity, displacement and cracking patterns of FPPC girder.

Given the excessive demolition of structures each year, the issues related to the generated structural waste are striking. Bricks being a major constituent in the construction industry, also hold a significant proportion of the construction waste generated annually. The reuse of this brick waste in new constructions is an optimal solution considering cost-effectiveness and sustainability. However, the problems related to the substandard peak stress and ultimate strain of concrete constructed with recycled brick aggregates (CRAs) limit its use in non-structural applications. The present study intends to improve the unsatisfactory mechanical characteristics of CRAs by utilizing low-cost glass fiber chopped strand mat (FCSM) sheets. The efficacy of FCSM sheets was assessed by wrapping them around CRA specimens constructed with different concrete strengths. A remarkable increase in the peak compressive stress and the ultimate strain of the CRA specimens were observed. For low, medium, and high strength CRAs, the ultimate strain improved by up to 320%, 308%, and 294%, respectively, as compared to the respective control specimens. Several existing analytical models were utilized to predict the peak compressive stress and ultimate strain of the CRAs strengthened using FCSM sheets. None of the considered models reproduced experimental results accurately. Therefore, equations were formulated using regression predicting the peak stress and ultimate strain of the CRAs confined with FCSM sheets. The predicted values were found to correlate well with the experimental values.

Floods are among the major natural disasters that cause loss of life and economic damage worldwide. Floods damage homes, crops, roads, and basic infrastructure, forcing people to migrate from high flood-risk areas. However, due to a lack of information about the effective variables in forecasting, the development of an accurate flood forecasting system remains difficult. The flooding process is quite complex as it has a nonlinear relationship with various meteorological and topographic parameters. Therefore, there is always a need to develop regional models that could be used effectively for water resource management in a particular locality. This study aims to establish and evaluate various data-driven flood forecasting models in the Jhelum River, Punjab, Pakistan. The performance of Local Linear Regression (LLR), Dynamic Local Linear Regression (DLLR), Two Layer Back Propagation (TLBP), Conjugate Gradient (CG), and Broyden–Fletcher–Goldfarb–Shanno (BFGS)-based ANN models were evaluated using R2, variance, bias, RMSE and MSE. The R2, bias, and RMSE values of the best-performing LLR model were 0.908, 0.009205, and 1.018017 for training and 0.831, −0.05344, and 0.919695 for testing. Overall, the LLR model performed best for both the training and validation periods and can be used for the prediction of floods in the Jhelum River. Moreover, the model provides a baseline to develop an early warning system for floods in the study area.

The present study focused on the development and application of two computer numerical models, namely, a seepage model developed using SEEP/W software and a groundwater model developed using Visual MODFLOW software. The seepage model was applied to a 38 km length of the tail reach of the Trimmu–Sidhnai (T-S) link canal passing through a severely waterlogged area of 32,000 ha, with a water table within 0–1.5 m from the ground surface; this was to quantify the canal seepage under the present condition (without any intervention) and with the interventions of a concrete lining of the complete prism of the T-S link canal and concrete side protection of the T-S link canal, with the canal bed unlined. The groundwater model evaluated the effectiveness of three waterlogging management interventions, which included: (i) the rehabilitation of the 43 existing drainage tube wells, (ii) the rehabilitation of the existing surface drains, and (iii) a combination of the rehabilitation of the 43 existing drainage tube wells and the rehabilitation of the existing surface drains. The seepage modeling revealed that the concrete lining intervention can reduce 50% of the seepage of the T-S link canal, whereas the concrete side protection intervention can reduce only 21% of the canal seepage. The groundwater modeling revealed that the waterlogging management intervention of the rehabilitation of the 43 drainage tube wells and surface drains can lower the groundwater level from 139.2 to 138.3 m (0.9 m drop), resulting in the mitigation of waterlogging in 45% (14,400 ha) of the severely waterlogged area. The present study recommends that complete concrete lining of the T-S link canal has a huge potential to reduce seepage from the canal, and the combination of the rehabilitation of the 43 drainage tube wells and surface drains also offers a great potential for controlling waterlogging. This intervention can also be considered to mitigate waterlogging from the severely waterlogged area. Cost-effectiveness analysis of the concrete lining of the T-S link canal, the rehabilitation of the 43 existing drainage tube wells, and the rehabilitation of the existing surface drains need to be performed for decision-making and selection of the most cost-effective intervention for implementation. A study needs to be conducted for the development and evaluation of economical and socio-technically feasible and acceptable preventive waterlogging management interventions, including the improved management of irrigation systems, improved irrigation management practices at the farm, improved conjunctive management of surface and groundwater, and improved management of drainage systems at the primary, secondary, and tertiary canal command levels.

Intrinsically, lightweight aggregate concrete (LWAC) suffers from the low compressive strength and deformation capacity. This restricts the use of LWAC mainly to non-structural applications. Several studies have highlighted the potential of synthetic fiber-reinforced polymer (FRP) jackets for improving the substandard properties of the LWAC. However, the high costs associated with FRP jackets are generally a concern. This study identifies hemp fiber-reinforced rope polymer (FRRP) wraps as a potential alternative to the synthetic FRP jackets. The salient features of hemp FRRP include its low cost and easy availability. Therefore, the main question that needs to be answered is: can hemp FRRP strengthen LWAC as a low-cost alternative to synthetic FRP jackets? To quantitatively explain the effects of lightweight aggregates on concrete compressive strength, 24 concrete cylinders were tested in three groups. Group 1, 2, and 3 cylinders comprised 0, 50, and 100% of lightweight aggregates as natural aggregate replacements. The peak stress of the concrete was reduced by 34% and 49% in the presence of 50% and 100% lightweight aggregates, respectively. It was concluded that a single layer of hemp FRRP on Group 2 cylinders (i.e., 50% aggregate replacement) was sufficient to enhance the peak stress to the same level as that of the control cylinder in Group 1 (i.e., fabricated using natural aggregates only). At the same time, it took two layers of external FRRP on Group 3 cylinders to achieve the same strength. A positive correlation between the peak stress of the LWAC and the number of hemp FRRP layers was observed. Nonetheless, Group 1 and 3 cylinders formed the upper and lower bounds in terms of peak stress for the same level of confinement. Further to the interest, three layers of hemp FRRP shifted brittle compressive stress–strain response to a bi-linear response for all amounts of lightweight aggregates. Several existing analytical peak stress models were assessed in predicting the experimental results. From the results, it was inferred that none of these models predicted the compressive strength of all three groups of cylinders consistently.

Recycled aggregate concrete (RAC) is more sustainable, eco-friendly, and cost-effective as compared to natural aggregate concrete (NAC). Among recycled aggregates (RAs), clay brick aggregate (CBA) has the potential of being the most widely used RAs because of the considerable amount of clay brick waste generated in many countries. The compressive behavior and mechanical properties of RAC with CBA are highly influenced by the mechanical properties of bricks. The stiffness and compressive strength of RAC with CBA are reported marginally lower than the natural aggregate concrete (NAC). In the past, different types of fiber reinforced polymer (FRP) composites such as carbon FRP, glass FRP, and aramid FRP have been investigated to enhance the strength and stiffness of the RAC with CBA. However, the behavior of hybrid FRP confined RAC with CBA is not yet clear. In this study, the performance of a new, low-cost and high-performance hybrid composite to enhance the strength and stiffness of the RAC with CBA is investigated. Hybrid composite is developed by using natural Basalt fiber and E-glass fibers (Chopped Strand Mat) along with the use of high-performance polyester resin. Three types of bricks (having different strength and water absorption) were used to produce CBA. Other research parameters included were the strength of RAC with CBA and the number of layers of hybrid basalt/E-glass fiber reinforced polymer (BE-FRP) composite. A total number of 36 concrete cylinders (12 un-confined and 24 confined with BE-FRP) were tested under pure axial compressions. The results indicate that the BE-FRP composites are highly suitable to enhance strength, stiffness, and ductility of the RAC with CBA. Also, there was found a significant increase in strength and ductility with an increase in the confinement level. In the end, the efficiency of existing strength and stain models was assessed to predict the ultimate strength and strain of the BE-FRP confined RAC with BAC.

Full-scale testing of multiple span girders is scarce in the literature, often related to the complexity of loading setup and time constraints. The importance of full-scale tests is manifested in the fact that useful information regarding failure mechanisms can be obtained. In addition, important guidelines can be established for structural designers. Further, results from full-scale tests can help establish constitutive laws for various mechanisms involved in the response of actual structures. The structural performance of individual members can be assessed by monitoring their strains at service and ultimate loads. This study presents a comparison of experimentally monitored strains on longitudinal steel bars, stirrups, and prestressing tendons embedded in single and multi-span full-scale precast pre-tensioned girders. These girders were constructed and detailed to simulate the response of newly proposed straddle-type monorail girders. Single-span girders were tested under monotonic two-point service and ultimate loads, whereas multi-span girders were tested under both two- and four-point service and ultimate load. It was revealed that longitudinal steel and prestressing tendon strains monitored within single-span girders at service and ultimate loads were significantly higher than those recorded at corresponding locations in multi-span girders.

Salient features of lightweight aggregate concrete (LAC) include noticeable fire resistance, high strength-to-weight ratio, and low magnitude of dead loads. Further, LAC has a low cost, eases construction practices, and possesses an environment-friendly nature. On the downside, LAC has substandard mechanical properties in comparison to normal aggregate concrete. Natural fiber-reinforced polymers (FRPs) have shown their potential in ameliorating the mechanical properties of natural aggregate concrete. So far, no study has been conducted to assess the efficacy of hemp rope confinement to strengthen lightweight aggregate concrete especially comprising rectilinear sections. This study aimed to overcome the substandard nature of LAC. A low-cost, sustainable, and environmentally green solution in the form of natural hemp rope layers is proposed. Twenty-four square concrete specimens were tested in three groups depending upon the presence and quantity of lightweight aggregates. It was found that concrete constructed with lightweight aggregates demonstrated lower ultimate compressive strength and strain as compared to normal aggregate concrete. Hemp rope-confined LAC showed enhanced ultimate compressive strength and strain. This enhancement was found to increase with the number of hemp rope layers. Several existing ultimate stress models were assessed to predict the ultimate compressive strength of the hemp rope-confined specimens. Only a single model was able to predict the ultimate compressive strength of the hemp rope-confined specimens with reasonable accuracy.

As everyone spends much time traveling, engaged in leisure or work activities, travel time represents one of the largest costs to transportation. The main objective of the study is to investigate travelers’ perceptions related to value of travel time saving with the help of a questionnaire survey. The survey was conducted online with the help of Google forms. The required data were collected through a self-reported questionnaire that consisted of five parts. A total of 312 useable sample responses were collected. The collected data were analyzed using conventional and statistical methods. In conventional methods, frequency distribution was carried out, and bar and pie charts were prepared. In the statistical methods, the exploratory factor analysis method (EFA) was conducted to extract useful factors affecting the travelers’ perceptions about travel time saving attitude. The survey results showed that more than 73% of people use a car for transport, which implies that most of them do not like to wait for public transport modes. It means that their travel attitudes are more inclined towards private transport seeking travel time saving. Most people do not like to share space with others while traveling, amounting to 44% of respondents using private cars alone, and placing high importance on flexibility, reliability, and time and cost saving in traveling, which implies that they are more likely to travel alone to save travel time. In addition, most of the respondents use short routes; this propensity is positively related to time and cost saving factors. Similarly, the time and cost savings and car-oriented attitudes are positively associated with the choice of a short route to save travel time. They also believe that the service quality level of transportation facilities affects the travel time saving and its value. This study proposes to improve travel time and cost in Oman.

The aim of this research work is to investigate the efficiency of newly developed Natural Fiber Rope Reinforced Polymer (NFRRP) composites to enhance the shear strength of reinforced concrete (RC) beams. Two types of NFRRP composites were made using low-cost hemp and cotton fiber ropes. The effectiveness of this NFRRP confinement in increasing the shear, energy dissipation, and deformation capacities of concrete beams was studied. The effect of these natural fiber ropes with different configurations on beams was investigated. The responses of seven RC beams with different spacing arrangements of natural fiber ropes were evaluated in terms of shear enhancement, deflection, energy dissipation capacity, effect of strengthening configuration, rope types, and ultimate failure modes. The NFRRP composites exceptionally enhanced the load carrying abilities, energy dissipation, and deformation capabilities of RC beams as compared to the control beam. The ultimate load carrying capacities of natural hemp and cotton Fiber Rope Reinforced Polymer (FRRP) composite confined beams were found to be 63% and 56% higher than that of the control beam, respectively. Thus, the shear strengthening of RC beams using natural fiber ropes is found to be an effective technique. Finite Element Analysis was also carried out by using the Advanced Tool for Engineering Nonlinear Analysis (ATENA) software. The analysis results compare favorably with the tests’ results.

Reinforced concrete is used in the construction of bridges, buildings, retaining walls, roads, and other engineered structures. Due to seismic activities, a lot of structures develop seismic cracks. The rehabilitation of such structures is necessary for public safety. The overall aim of this research study was to produce a high-performance hybrid fiber-reinforced concrete (HPHFRC) with enhanced properties as compared to plain high-performance concrete and high-performance fiber-reinforced concrete (HPFRC) for the rehabilitation of bridges and buildings. Kevlar fibers (KF) and glass fibers (GF) with lengths of 35 mm and 25 mm, respectively, were added and hybridized to 1.5% by mass of cement to create hybrid fiber-reinforced concrete mixes. Eight mixes were cast in total. The compressive strength (f′c), flexural strength (fr), splitting tensile strength (fs), and other mechanical properties, i.e., energy absorption and toughness index values, were enhanced in HPHFRC as compared to CM and HPFRC. It was found that the concrete hybridized with 0.75% KF and 0.75% GF (HF-G 0.75 K 0.75) had the most enhanced overall mechanical properties, illustrating its potential to be utilized in the rehabilitation of bridges and structures.

Over the last two decades, considerable attention has been devoted to the strengthening of sub-standard flat-slab constructions. With the evolution of composite materials and an increasing emphasis on the economical and sustainable use of natural fibers, many researchers have utilized them in the strengthening of flat flabs mitigating punching failures. This study aims at investigating and comparing the behavior of flat slabs strengthened with post-installed composite and natural reinforcements. An experimental program was devised consisting of eight flat-slab specimens. One specimen was tested in as-built condition to provide a reference. The remaining specimens were strengthened with Carbon Fiber-Reinforced Polymer (CFRP), Aramid Fiber-Reinforced Polymer (AFRP), and sisal rods. The pattern of post-installed rods was varied as single line, double line, and star shapes around the column. The results indicated that the single-line pattern could only enhance the maximum sustained load by up to 6% compared to that of the reference specimen. On the contrary, double line and star shape configurations resulted in a substantial increase in the maximum sustained load. An analytical assessment of ACI 318-19 provisions resulted in an over-estimation of the shear strengths of CFRP- and AFRP-strengthened slabs. Furthermore, the same provisions led to lower yields than experimental shear strengths for sisal-strengthened slabs.

Environment-friendly concrete is gaining popularity these days because it consumes less energy and causes less damage to the environment. Rapid increases in the population and demand for construction throughout the world lead to a significant deterioration or reduction in natural resources. Meanwhile, construction waste continues to grow at a high rate as older buildings are destroyed and demolished. As a result, the use of recycled materials may contribute to improving the quality of life and preventing environmental damage. Additionally, the application of recycled coarse aggregate (RCA) in concrete is essential for minimizing environmental issues. The compressive strength (CS) and splitting tensile strength (STS) of concrete containing RCA are predicted in this article using decision tree (DT) and AdaBoost machine learning (ML) techniques. A total of 344 data points with nine input variables (water, cement, fine aggregate, natural coarse aggregate, RCA, superplasticizers, water absorption of RCA and maximum size of RCA, density of RCA) were used to run the models. The data was validated using k-fold cross-validation and the coefficient correlation coefficient (R2), mean square error (MSE), mean absolute error (MAE), and root mean square error values (RMSE). However, the model’s performance was assessed using statistical checks. Additionally, sensitivity analysis was used to determine the impact of each variable on the forecasting of mechanical properties.

Fiber-reinforced concrete (FRC) is a competitive solution for the durability of reinforced structures. This paper aims to observe the moment redistribution behavior occurring due to flexural and shear loading in Glass Fiber-Reinforced Polymer- (GFRP) reinforced continuous concrete beams. A rectangular cross-section was adopted in this study with dimensions of 200 mm in width and 300 mm in depth with a constant shear span-to-depth ratio of 3. The reinforcement ratio for the top and bottom were equal at sagging and hogging moment regions. A finite element model was created using Analysis System (ANSYS) and validated with the existing experimental results in the literature review. Based on the literature review, the parametric study was conducted on twelve beam specimens to evaluate the influence of concrete compressive strength, transversal GFRP stirrups ratio, and longitudinal reinforcement ratio on the redistribution of the moment in beams. Several codes and guidelines adopted different analytical models. The Canadian Standards Association (CSA) S806 adopted the modified compression field theory in predicting the shear capacity of the simply supported beams. Recently, various researchers encountered several factors and modifications to account for concrete contribution, longitudinal, and transverse reinforcement. A comparison between the predicting shear capacity of the generated finite element model, the analytical model, and the existing data from the literature was performed. The generated finite element model showed a good agreement with the experimental results, while the beam specimens failed in shear after undergoing significant moment redistribution from hogging to sagging moment region. The moment distribution observed about 21.5% from FEM of beam specimen GN-1.2-0.48-d, while the experimental results achieved 24% at failure load. For high strength concrete presented in beam specimen GH-1.2-0.63-d, the result showed about 20.2% moment distribution, compared to that achieved experimentally of 23% at failure load.

An experimental program was conducted to ascertain the efficiency of Carbon Fiber Reinforced Polymer (CFRP) in enhancing the flexural response of hollow section reinforced concrete (RC) beams. Nine beams were tested under four-point bending in three groups. Beams were categorized to reflect the presence or configuration of the CFRP sheet. Each group consisted of three beams: one with a solid section, one with a square 50×50 mm × mm opening and 1 with 100×100 mm × mm opening. Beams in 1st group were tested in as-built conditions. Beams in the 2nd group were strengthened with a single CFRP sheet bonded to their bottom sides. Configuration of CFRP sheet was altered to U-shape applied to the tension side of 3rd group beams. The inclusion of openings, regardless of their size, did not result in degradation of ultimate load and corresponding deflections. However, cracking loads were found to decline as the opening size increased. Regardless of the opening size and CFRP configuration, ultimate loads of beams increased with the application of CFRP. However, this improvement was limited to the debonding and rupture of CFRP in group 2 and 3 beams, respectively. A comparison in the behavior of group 2 and 3 beams revealed that the application of the U-shape CFRP sheet yielded better flexural performance in comparison with the flat-CFRP sheet bonded to the bottom of beams. In the end, In order to further evaluate the economic and performance benefits of these beams, the cost-benefit analysis was also performed. The analysis showed that the feasibility of the hollow section RC beams is more than the solid section RC beams.

In the past, fiber-reinforced polymer (FRP) composites have been extensively used to modify the structural response of masonry brick walls. The promising advantages of FRP composites are easy application, lightweight, and very high tensile strength. However, FRP composites are very expensive, and their availability is an issue, especially in developing countries. The use of bricks is widespread in developing countries due to their low price and easy availability. Recent earthquakes and research results have demonstrated the vulnerability of existing masonry structures. In this study, we aimed to investigate the use of low-cost and readily available strengthening materials, i.e., cement-sand mortar and wire mesh, to enhance the flexural capacity of cement-clay interlocking brick (CCIB) masonry walls. The proposed strengthening materials were applied in different configurations and thicknesses. The experimental results indicated that using CS mortar and wire mesh is promising to enhance the flexural capacity of CCIB masonry walls. The flexural capacity and energy absorption capacity of the CCIB masonry wall (strengthened with 20 mm thick CS mortar and three layers of wire mesh) were 87% and 46% higher than the reference CCIB masonry wall. The results of this study can be used to improve the performance of masonry structures against earthquakes in the developing regions.

The current trend in modern research revolves around novel techniques that can predict the characteristics of materials without consuming time, effort, and experimental costs. The adaptation of machine learning techniques to compute the various properties of materials is gaining more attention. This study aims to use both standalone and ensemble machine learning techniques to forecast the 28-day compressive strength of high-performance concrete. One standalone technique (support vector regression (SVR)) and two ensemble techniques (AdaBoost and random forest) were applied for this purpose. To validate the performance of each technique, coefficient of determination (R2), statistical, and k-fold cross-validation checks were used. Additionally, the contribution of input parameters towards the prediction of results was determined by applying sensitivity analysis. It was proven that all the techniques employed showed improved performance in predicting the outcomes. The random forest model was the most accurate, with an R2 value of 0.93, compared to the support vector regression and AdaBoost models, with R2 values of 0.83 and 0.90, respectively. In addition, statistical and k-fold cross-validation checks validated the random forest model as the best performer based on lower error values. However, the prediction performance of the support vector regression and AdaBoost models was also within an acceptable range. This shows that novel machine learning techniques can be used to predict the mechanical properties of high-performance concrete.

Cement–clay Interlocking Hollow Brick Masonry (CCIHBM) walls are characterized by poor mechanical properties of bricks and mortar. Their performance is observed to be unsatisfactory under both gravity and seismic loads. There is an urgent need to develop sustainable, environmentally friendly, and low-cost strengthening materials to alter the structural behaviour of brick masonry walls in terms of strength and ductility. The results of an experimental investigation conducted on the diagonal compressive response of CCIHBM walls are presented in this study. In this experimental study, a total of six CCIHBM walls were constructed using cement–clay interlocking hollow bricks. One was tested as a control or reference wall, whereas the remaining walls were strengthened using cement mortar. In some walls, the cement mortar was also combined with the wire mesh. The research parameters included the type of Ordinary Portland Cement (OPC) (Type 1 and Type 2), thickness of cement mortar (10 mm and 20 mm), and layers of wire mesh (one and three layers). The experimental results indicate that control or unstrengthened CCIHBM walls failed in a very brittle manner at a very low ultimate load and deformation. The control CCIHBM wall, i.e., W-CON, failed at an ultimate load of 247 kN, and corresponding deflection was 1.8 mm. The strength and ductility of cement mortar and wire mesh-strengthened walls were found to be higher than the reference CCIHBM wall. For example, the ultimate load and deformation of cement-mortar-strengthened wall were found to be 143% and 233% higher than the control wall, respectively. Additionally, the ultimate failure modes of cement mortar and wire mesh strengthened were observed as ductile as compared to the brittle failure of reference wall or unstrengthened CCIHBM wall, which increased by 66% and 150% as compared with the control wall.

The casting and testing specimens for determining the mechanical properties of concrete is a time-consuming activity. This study employed supervised machine learning techniques, bagging, AdaBoost, gene expression programming, and decision tree to estimate the compressive strength of concrete containing supplementary cementitious materials (fly ash and blast furnace slag). The performance of the models was compared and assessed using the coefficient of determination (R2), mean absolute error, mean square error, and root mean square error. The performance of the model was further validated using the k-fold cross-validation approach. Compared to the other employed approaches, the bagging model was more effective in predicting results, with an R2 value of 0.92. A sensitivity analysis was also prepared to determine the level of contribution of each parameter utilized to run the models. The use of machine learning (ML) techniques to predict the mechanical properties of concrete will be beneficial to the field of civil engineering because it will save time, effort, and resources. The proposed techniques are efficient to forecast the strength properties of concrete containing supplementary cementitious materials (SCM) and pave the way towards the intelligent design of concrete elements and structures.

The innovation of geopolymer concrete (GPC) plays a vital role not only in reducing the environmental threat but also as an exceptional material for sustainable development. The application of supervised machine learning (ML) algorithms to forecast the mechanical properties of concrete also has a significant role in developing the innovative environment in the field of civil engineering. This study was based on the use of the artificial neural network (ANN), boosting, and AdaBoost ML approaches, based on the python coding to predict the compressive strength (CS) of high calcium fly-ash-based GPC. The performance comparison of both the employed techniques in terms of prediction reveals that the ensemble ML approaches, AdaBoost, and boosting were more effective than the individual ML technique (ANN). The boosting indicates the highest value of R2 equals 0.96, and AdaBoost gives 0.93, while the ANN model was less accurate, indicating the coefficient of determination value equals 0.87. The lesser values of the errors, MAE, MSE, and RMSE of the boosting technique give 1.69 MPa, 4.16 MPa, and 2.04 MPa, respectively, indicating the high accuracy of the boosting algorithm. However, the statistical check of the errors (MAE, MSE, RMSE) and k-fold cross-validation method confirms the high precision of the boosting technique. In addition, the sensitivity analysis was also introduced to evaluate the contribution level of the input parameters towards the prediction of CS of GPC. The better accuracy can be achieved by incorporating other ensemble ML techniques such as AdaBoost, bagging, and gradient boosting.

Experimental evidence have proved that punching shear capacity of flat slabs deteriorate with the presence of openings located within the critical perimeter around columns. It is understood that this deterioration varies inversely with the distance of openings from column’s face. However, effect of the shape of openings on punching shear capacity is not well known. This study presents experimental results of 14 flat specimens to investigate the effects of the number (2 and 4), shape (circular, square, and rectangular), and location (1 and 4 times of slab’s thickness from column’s face) of openings on punching shear strength. It was found that circular openings had least influence on punching capacity followed by square and rectangular openings, respectively. Further, placing openings at a distance of four times the slab’s thickness from column’s face had minimal impact on punching capacity. Further, increasing the number of openings from 2 to 4 substantially reduced the punching capacity. An effort was made to predict the punching capacities of all specimens using the descriptive equations of ACI 318-19 and Eurocode 2. Mean of the ratio of experimental to analytical results and standard deviation of ACI equations were found to be more accurate than those of Eurocode 2 predictions.

Experimental and finite element analysis results of reinforced concrete beams under monotonic loading were presented in this study. In the experimental program, one beam was tested in an as-built condition. The other two beams were strengthened using natural hybrid FRP layers in different configurations. The natural hybrid FRP composite was developed by using natural jute FRP and basalt FRP. One of the most appealing advantages of natural fiber is its beneficial impact on the environment, which is necessary for the sustainability recognition as an alternative to synthetic FRP. The hybrid FRP was applied to the bottom concrete surface in one beam, while a U-shaped strengthening pattern was adopted for the other beam. The flexural behavior of each beam was assessed through strain measurements. Each beam was incorporated with conventional strain gages, as well as the Brillouin Optical Time Domain Analysis (BOTDA) technique. BOTDA has its exclusive advantages due to its simple system architecture, easy implementation, measurement speed, and cross-sensitivity. The experimental results revealed that the beam strengthened with the U-shaped hybrid FRP composite pattern had a better flexural response than the other counterpart beams did both in terms of peak loads and maximum bottom longitudinal steel bar strains. Beams B-01 and B-02 exhibited 20.5% and 28.4% higher energy dissipation capacities than the control beam did, respectively. The ultimate failure of the control beam was mainly due to the flexural cracks at very low loads, whereas the ultimate failure mode of FRP composite-strengthened beams was due to the rupture of the hybrid FRP composite. Further, strain measurements using BOTDA exhibited similar patterns as conventional strain gage measurements did. However, it was concluded that BOTDA measurements were substantially influenced by the bottom flexural cracks, ultimately resulting in shorter strain records than those of conventional strain gages. Nonlinear structural analysis of the beams was performed using the computer program ATENA. The analytical results for the control beam specimen showed a close match with the corresponding experimental results mainly in terms of maximum deflection. However, the analytical peak load was slightly higher than the corresponding experimental value.

This research investigates the behavior of square concrete columns externally wrapped by low-cost and easily available fiber rope reinforced polymer (FRRP) composites. This study mainly aims to explore the axial stress-strain relationships of FRRP-confined square columns. Another objective is to assess suitable predictive models for the ultimate strength and strain of FRRP-confined square columns. A total of 60 square concrete columns were cast, strengthened, and tested under compression. The parameters were the corner radii of square columns (0, 13, and 26 mm) and different materials of FRRP composites (polyester, hemp, and cotton FRRP composites). The strength and deformability of FRRP-confined specimens were observed to be higher than the unconfined specimens. It was observed that strength gains of FRRP-confined concrete columns and corner radii were directly proportional. The accuracy of ultimate strength and strain models developed for synthetic FRRP-confined square columns was assessed using the test results of this study, showing the need for the development of improved predictive models for FRRP-confined square columns. Newly developed unified models were found to be accurate in predicting the ultimate strength and strain of FRRP-confined columns.

The results of an experimental program on shear-strengthening of flat slabs using Glass Fiber Reinforced Polymer (GFRP) rods are presented. A total of seven specimens were tested under an upward concentric monotonic loading until failure. One specimen served as a control and was tested without any modification. The remaining six specimens were strengthened with post-installed GFRP rods in single (SG), double (DB), and radial (RD) patterns within shear critical parameters around the centric column. The results of this experimental study suggest that GFRP rods are capable of enhancing both the peak load and deformation capacity. Furthermore, brittle failure associated with punching shear failure was successfully avoided by all strengthening patterns. Of all of the patterns, the RD pattern resulted in maximum peak load increase and corresponding deformation capacity while the lowest bound was created by the SG pattern. The results suggested that SG, DB and RD patterns enhanced ultimate loads up to 9.1, 11.3 and 15.7% while corresponding deflections increased up to 109, 136 and 154%. Strain measurement on flexural reinforcement suggested that all strengthened specimens were able to withstand higher longitudinal strains than yield. It was further shown that reducing the spacing between the GFRP rods efficiently enhanced peak loads, nevertheless, neither this change was proportional, nor did it result in an enhanced energy dissipation capacity. In the end, recommendations of American Concrete Institute (ACI) for the shear strength of two-way systems were modified to incorporate the contributions from GFRP rods. The results indicate that the proposed analytical approach provides an excellent match with the experimental results.

The aim of this research was to study the production of calcium sulfoaluminate (CSA) cement from several industrial waste materials including with marble dust waste, flue gas desulfurization gypsum, ceramics dust waste, and napier grass ash. The chemical composition, microstructure, and phase composition of raw materials were examined using energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. All raw wastes were analyzed using their chemical composition to assign proportion for raw mixture. The raw mixture is calcined at controlled calcination temperatures ranging from 1200 °C to 1300 °C for 30 min. Subsequently, with analysis, their phase composition is calculated by the Rietveld refinement technique. The results suggested that phase composition of clinker calcined at 1250 °C shows the closest composition when compared to target phases, and was selected to prepare CSA cement. The FTIR analysis was performed to study the hydration processes of CSA cement. The Ordinary Portland cement (OPC) based with adding CSA cement between 20 wt.% and 40 wt.% were investigated for the effect of CSA cement fraction on water requirement, setting times and compressive strength. The results showed that rapid setting and high early strength can be achieved by the addition of 20−40 wt.% CSA cement to OPC.