Natural fiber-reinforced polymers (FRP) offer a potential alternative for strengthening applications, specifically in cases where the costly nature of synthetic FRP composites is a worry. This work investigates the effects of basalt fiber-reinforced polymers (BFRP) confinement on flexural behavior, peak loads, and bond strength enhancement by conducting four-point bending tests on simply supported reinforced concrete (RC) beams. Large-scale beams were tested in two groups to differentiate lap splice length. Group 1 beams incorporated a lap splice length of 20db, whereas a 30db lap splice length was used in Group 2 beams (where db is the diameter of lap spliced bars). The findings show that BFRP confinement significantly affects flexural stiffness, improves ultimate strength and ductility. Peak load improvement varies with lap splice length, with Group 1 beams showing up to 80.95

The excessive consumption of natural sand and cement in mortar production raises environmental concerns, underscoring the need for sustainable alternatives. While the separate use of cementitious and fine aggregate substitutes has been studied, their combined effects in self-compacting mortar (SCM) remain underexplored. This study addresses this gap by investigating SCM mixes incorporating calcium carbonate (CaCO3) as a partial cement substitute (0-20%) and waste garnet (0-100%) as a fine aggregate replacement. A total of 18 mixes were evaluated for their fresh properties, mechanical performance, durability, and residual properties after elevatedtemperature exposure. The results showed that the mix with 10% CaCO3 and 60% waste garnet exhibited the best overall performance, achieving approximately 66 MPa compressive strength and 8.1 MPa flexural strength at 90 days, representing up to a 15% improvement over the control. Water absorption was reduced to 2.42% at 90 days, while improved resistance under acidic conditions was observed, with only 7.71% mass loss after 180 days of exposure to 5% H2SO4 solution. Furthermore, the optimized mix retained over 65% of its compressive strength after exposure to 600 degrees C, indicating good residual mechanical performance at elevated temperatures. Microstructural analysis revealed a dense and cohesive matrix with a refined pore structure. These findings suggest that the combined use of CaCO3 and waste garnet can provide a potentially eco-efficient approach for producing high-performance SCM. The improved workability, strength, and durability indicate potential suitability for applications such as repair mortars and precast elements, where both flowability and long-term performance are required.

This study addresses the growing need for sustainable and cost-effective alternatives to conventional fiber-reinforced polymer (FRP) confinement systems, particularly for recycled aggregate concrete (RAC) subjected to elevated temperatures. The axial compressive behavior of hemp rope-confined RAC cylinders was experimentally investigated under ambient and moderate thermal exposure (150 degrees C). Two strength grades were considered, with confinement applied using one to three layers of hemp rope. The results demonstrate that hemp confinement significantly enhances both compressive strength and axial strain, with improvements increasing with the number of layers, while strain enhancement was consistently more pronounced than strength gain. The stress-strain response exhibited a characteristic two-stage behavior, consisting of an initial unconfined-like region followed by a confinement-activated ascending branch. The elastic modulus of RAC was found to be approximately 21.9% to 29.7% lower than ACI 318-19 predictions, suggesting a reduction factor of about 25% for practical applications. Thermal exposure had a limited effect on normalized strength and strain parameters, although post-peak stiffness showed some sensitivity. Notably, confinement proved even more effective in thermally damaged specimens due to increased lateral deformability. A regression-based analytical model was developed to predict the complete stress-strain response, showing close agreement with experimental results. This study is among the first to evaluate the performance of hemp rope confinement for RAC under elevated temperature conditions and to propose a unified predictive framework. Overall, the findings confirm that hemp rope confinement is an effective, sustainable, and reliable technique for enhancing both the strength and ductility of RAC, with strong potential for structural applications, including post-fire rehabilitation.

This study examined the axial behaviour of recycled brick aggregate concrete (RBAC) confined with glass chopped strand mat (GCSM) through an extensive experimental and analytical program. The results demonstrated that GCSM confinement markedly improved both compressive strength and ductility, with strength gains of up to 75% and peak strain increases exceeding 80% in low-strength (LS) mixes, while medium- and high-strength (MS and HS) mixes showed comparatively lower enhancements. Specimens made with type B bricks consistently outperformed those with type C in both strength and deformability, and the confinement effect was most pronounced in LS concretes due to their greater initial ductility and ability to activate external wraps. Confined specimens exhibited improved post-peak behaviour, with positive post-peak modulus values and deformability indices up to 2.6 times higher than unconfined counterparts. Analytical models developed for normalized strength, peak strain, post-peak modulus, and deformability index showed strong agreement with experimental data (R2 = 0.86-0.98) and accurately reproduced full stress–strain responses. These models incorporate key confinement parameters, lateral pressure, brick strength, and unconfined concrete strength, enabling their direct use in design and assessment of GCSM-confined RBAC elements. Overall, GCSM provides a simple, affordable, and sustainable confinement system, offering a practical retrofitting solution for enhancing the strength and ductility of structural concrete, particularly in resource-constrained and sustainability-focused regions.

Growing environmental concerns related to cement production, excessive natural sand extraction, and the accumulation of non-biodegradable waste have increased the demand for sustainable construction materials. In this context, valorizing industrial and agricultural wastes in concrete provides an effective strategy for reducing environmental burdens while supporting circular economy principles and sustainable development goals. This study explores the use of sustainable self-compacting concrete (SCC) incorporating recycled tempered glass (RTG) as a partial fine aggregate replacement, waste cotton rope fibers as reinforcement, and nano-calcium carbonate (nano-CaCO3) as a micro-filler. A key contribution is investigating the combined effects of RTG and natural fibers on fresh, mechanical, durability, thermal, and microstructural properties of SCC, largely unexplored in previous studies. Thirteen SCC mixes were prepared with varying RTG levels (10-50%) and cotton rope fiber dosages (0.1-0.3%), with 2% nano-CaCO3 partially replacing cement. Workability was assessed through slump flow, T500, J-ring, L-box, and Vfunnel tests. Strength, durability, thermal, and microstructural properties were thoroughly evaluated. The results revealed that moderate RTG replacement (10-20%) enhanced strength, reduced water absorption, and improved sulfate resistance. However, higher RTG (>= 30%) or excessive fibers (0.3%) led to increased porosity and performance loss. Thermal analysis indicated a decrease in conductivity with increasing RTG content, while scanning electron microscopy (SEM) confirmed matrix densification and effective fiber bridging at optimum dosages. These findings demonstrate the feasibility of integrating RTG and cotton fibers into SCC, offering an ecoefficient pathway to sustainable and durable concrete when material proportions are appropriately optimized.

RNAi has emerged as a potential agricultural technology to control insect pests. Pink Bollworm (PBW) is a notorious insect pest of cotton that causes loss of millions of bales. We aim to silence the Vacuolar ATPase subunit C (V-ATPase) gene in PBW to disrupt essential functions, thereby enhancing its susceptibility to Bt toxins and providing an additional layer of crop protection. Two dsRNA fragments were designed, and their efficacy was determined through an oral feeding assay. Mortality rates for PBW larvae were 36

This research experimentally assesses the flexural strengthening of reinforced concrete (RC) beams through the use of sustainable jute–basalt (JB) hybrid fiber-reinforced polymer (FRP) systems with variable wrapping schemes and lightweight aggregate (LWA) replacement. A total of 18 beams with identical geometry and reinforcement were tested under four-point bending, including controls, basalt FRP (BFRP), jute FRP (JFRP), and hybrid JB FRP systems in bottom-only, U-wrap, and full-wrap configurations. The results indicate that FRP confinement significantly modified failure modes, transitioning from the brittle crushing in controls to rupture- or debonding-controlled mechanisms. BFRP significantly enhanced strength, achieving up to 36.8% greater capacity in full-wrap beams, while JFRP improved ductility but was more prone to premature debonding. Hybrid JB FRP systems demonstrated the most balanced performance, with U-wrap hybrids achieving 39.6% higher load capacity and maintaining significant deformation capacity even in LWA concrete. Load–strain responses confirmed yielding of steel reinforcement in all cases, though maximum strains were reduced after confinement due to premature fiber debonding or rupture at smaller deflections. The use of LWA reduced ductility of control beams, but hybrid U-wrap systems successfully compensated for this limitation, providing the highest load and deflection values among all specimens. These results emphasize the potential of hybrid natural–mineral FRP systems as sustainable alternatives to synthetic composites, providing competitive ductility and reinforcement for structural retrofitting applications in both conventional and lightweight concretes.

This study uniquely examines the effectiveness of basalt fiber-reinforced polymer (BFRP) wraps in enhancing the mechanical properties of recycled brick aggregate concrete (ReBAC) square concrete columns, using both fired clay solid and hollow brick aggregates. This combination is relatively unexplored in existing literature. Furthermore, this study promotes waste reduction and resource efficiency, minimizing the environmental impact of concrete production. A total of 64 square concrete specimen types were employed in this work. The magnitude of BFRP confinement was increased by two, four, or six layers. The natural coarse aggregates were replaced by 50% or 100% recycled brick aggregates. Two types of bricks were considered, that is, fired-clay solid or fired-clay hollow bricks. The results demonstrate that BFRP wraps significantly improve the compressive strength by up to 130.76% and ultimate strain by up to 1800%, with higher improvements observed in concrete made with CBB bricks due to their superior compressive strength and lower water absorption. The confinement effect, which becomes active only after significant axial deformation, is positively influenced by the number of wraps, with the confinement ratio emerging as a key parameter for strength and strain improvements. The study also presents regression-based design-oriented models for the compressive behavior of BFRP-confined ReBAC, showing good correlation with experimental results and highlighting the importance of aggregate properties in analytical modeling. The findings suggest that BFRP is an effective and sustainable solution for strengthening ReBAC, with potential for use in structural applications.

This study presents a comprehensive scientometric review of cement-less ultra-high-performance concrete (UHPC) with the objective of identifying research trends, key contributors, dominant themes, and critical knowledge gaps in this emerging field. A systematic bibliometric analysis was conducted using the Scopus database, from which 59 peer-reviewed journal articles published between 2014 and 2024 were selected following rigorous screening criteria. Scientometric mapping was performed using VOSviewer to analyze publication trends, keyword co-occurrence, leading journals, influential authors, and active research regions. The findings reveal a sharp increase in research output after 2020, reflecting growing interest in geopolymer-based UHPC due to sustainability concerns. Existing studies predominantly focus on mechanical properties, particularly compressive strength and steel fiber reinforcement, while durability-related aspects such as corrosion resistance, fire performance, and long-term structural behavior remain underexplored. Higher sand-to-binder ratios (up to 0.8) were found to improve packing density and mechanical performance, achieving compressive strengths up to 160.7 MPa, while silica fume contents around 30% enhanced compressive strength by approximately 25% and fracture energy by nearly 50%. The novelty of this work lies in being the first dedicated scientometric assessment of cement-less UHPC, providing a quantitative overview of research evolution while systematically highlighting critical gaps and future research directions to support its effective structural application.

This study investigates the application of machine learning (ML) models to predict the ultimate failure load of reinforced concrete (RC) beams confined with low-cost fiber-reinforced polymers (FRP), relatively underexplored area. A dataset of 100 samples, including beams designed to fail in flexure and shear, was compiled from literature and experimental testing. Four ML models-XGBoost, Random Forest (RF), Neural Network (NN), and Decision Tree (DT)-were evaluated using k-fold cross-validation with performance metrics such as Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE), and R2. XGBoost outperformed the other models, achieving the highest R2 of 0.96 and the lowest RMSE of 12.81, while SHAP analysis identified beam height, bottom rebar strength, and beam width as key predictors. These results highlight the effectiveness of ensemble methods for predicting failure loads in RC beams and provide insights into the most influential features affecting structural performance.

The growing demand for sustainable construction highlights the need for innovative concrete solutions using waste materials. Although recycled concrete aggregate (RCA), polyvinyl alcohol (PVA), and recycled electronic waste fibers (E-waste fibers) have been studied individually, their combined effects remain underexplored. This study addresses this gap by investigating the synergistic effects of coarse RCA (CRCA) and E-waste fibers on the fresh, mechanical, durability, thermal, and economic properties of green concrete. Fly ash replaced 20 % of cement, and PVA was added at 1 % by cement weight. Results showed that increasing CRCA content reduced workability and strength due to porosity. However, incorporating 4.5 % E-waste fibers significantly improved mechanical performance by bridging microcracks. Higher fiber contents negatively affected durability and workability. Thermal conductivity decreased with more CRCA and fibers, enhancing insulation. Economic analysis confirmed that 4.5 % E-waste fiber offers cost-effective performance. This study supports the sustainable use of electronic and construction waste in concrete.

This paper examines diatomite (DM) and sugarcane bagasse ash (SBA) for use as partial replacements for fine aggregates in the manufacture of hollow concrete blocks, which are used in non-structural applications. Several key findings were recorded through tests on mechanical and durability performance. Substitution of fine aggregates with DM or SBA significantly reduced the bulk density, with SBA having a slightly higher reduction. Concrete compressive strength stabilizes after 28 days, with 20% replacement of DM and SBA resulting in significant strength reductions-83.7% for DM and 46.2% for SBA. Thermal conductivity showed a remarkable reduction of 65.4% and 47.3%, respectively. Moreover, the DM addition significantly improved the sound absorption capacity due to the increased void fraction. These results underline the viability of DM and SBA as sustainable alternatives to fine aggregates, exhibiting superior thermal and acoustic performances besides offering solutions to environmental concerns on the use of wastes.

This study investigates the bond strength between recycled brick aggregate concrete (RBAC) and un-strengthened lap spliced reinforcing steel bars, contributing to sustainable construction practices. The research examines the effects of partial replacement of natural coarse aggregate (NCA) with recycled brick aggregates, concrete cover to bottom bar diameter ratio, and lap splice lengths on bond strength. Hardened properties of RBAC, having 20

This study investigates the use of cotton ropes (CRs) as a sustainable and cost-effective substitute for synthetic fiber-reinforced polymers for concrete confinement, offering significant environmental benefits such as lower CO2 emissions and reduced energy consumption. The work evaluates the effectiveness of CR strips for confining concrete, including scenarios with recycled concrete aggregates (ReCA). Compressive strength improvements varied among specimens, with Specimen I-3F showing a 140.52% increase and Specimen II-3F achieving a 46.67% improvement. Strip configurations for Type I recycled aggregate concrete (RAC) outperformed full wraps on Type II RAC, exemplified by Specimen I-3S’s 84.51% improvement. Ultimate strain enhancements ranged from 915% to 4490.91%, driven by the significant rupture strain of cotton rope confinement. For Type I RAC, complete wrapping significantly outperformed strip configurations by 56%, 50%, and 32% in ultimate strength improvement for 1, 2, and 3 layers, respectively. The confinement ratio, varying from 0.10 to 0.70, greatly influenced the compressive behavior, with compressive strength normalized by unconfined strength increasing consistently with the confinement ratio. A minimum confinement ratio of roughly 0.40 is required to achieve an increasing second part in the compressive behavior. The initial parabolic branch was modeled using Popovics’ formulation, revealing an elastic modulus approximately 20% lower than ACI 318-19 predictions. The second branch was described using a linear approximation, and nonlinear regression analysis produced expressions for key points on the idealized compressive curve, enhancing model accuracy for CR-confined RAC. The R2 values for the nonlinear regression analysis performed on experimental results were greater than 0.90. This study highlights the effectiveness of neural network expressions to predict the compressive strength of CR-confined concrete. A strength reduction (ratio of full wrap and strip wrap height CRs) factor of 0.67 was proposed and used for strip-wrapped specimens. It was seen that the neural network models also predicted the compressive strength of partially wrapped specimens with reasonable accuracy using the strength reduction factor.

This study experimentally evaluated the effectiveness of Carbon Fiber Reinforced Polymer (CFRP) and Fabric Cementitious Matrix (FCSM) sheets in enhancing the structural performance of one-way reinforced concrete slabs under three-point bending. Fourteen slabs were tested, considering key variables such as the number of FCSM sheets, type, size, and spacing of anchors to mitigate debonding. Results revealed that slabs strengthened with FCSM sheets and epoxy anchors demonstrated peak capacity improvements of up to 151 %, while mechanical anchors yielded a peak improvement of 95 %. Epoxy anchors also enhanced energy dissipation by up to 222 %, surpassing the 76 % maximum improvement observed with mechanical anchors. However, slabs with more than two FCSM layers required robust anchorage systems to maintain increased capacity without significant drops due to debonding. Slabs with epoxy anchors showed higher peak capacities but were more prone to abrupt post-peak losses than those with mechanical anchors. These findings underline the critical role of anchor type and configuration in optimizing the flexural and energy dissipation performance of strengthened slabs, providing valuable insights for sustainable and effective retrofitting strategies. Finite element modeling of slabs strengthened with FCSM, assuming no debonding, was carried out using ATENA software. The adopted modeling approach yielded slightly overestimated predictions of ultimate loads. As this represents initial research in the field, further investigations are recommended to develop more accurate and refined constitutive laws for FCSM to enhance the reliability of FEM simulations.

This paper presents experimental findings from testing seventeen reinforced concrete deep beams, categorized into four groups based on the presence and type of openings. A novel and cost-effective hybrid strengthening scheme is proposed comprising glass chopped mat sheets and eco-friendly basalt FRP sheets (GF-BFRP). Group 1 consisted of solid beams without openings, while Group 2 included beams with circular openings, Group 3 with square openings, and Group 4 with rectangular openings of varying dimensions. Each group comprised beams tested in various strengthening configurations using GF-BFRP layers with and without anchor support. Analysis of failure modes revealed initial flexural cracking in control beams, with beams containing openings exhibiting diagonal cracking and reduced shear capacity. Results revealed that beams with openings experienced a significant reduction in shear capacity. Circular, square, and rectangular openings reduced peak capacity by 26.11%, 30.67%, and 31.91%, respectively, while rectangular openings oriented vertically caused the most substantial reduction at 47.46%. Strengthening using a single GF-BFRP sheet led to debonding, which was mitigated by anchors, enhancing confinement and reducing diagonal cracking. However, strengthened beams did not recover the original strength of the solid beam, which reached a peak load of 245.51 kN. For instance, the C-W1-A beam achieved a peak load of 173.58 kN, which was 4.31% lower than its control beam due to the extensive anchor installation. Evaluation of predictive models for shear capacity highlighted discrepancies. None of the existing codes provide expressions that account for the shear contributions of externally bonded FRP systems on beams with opening shape and size implicitly defined. To overcome this issue, machine learning approaches were utilized, employing gradient boosting regression and random forest methods. Data on deep beams, both with and without openings (and without strengthening), was collected from eight studies. The models were trained on this dataset, and predictions were made based on the results of this study. While the gradient boosting regression model tended to overestimate the peak capacity of the deep beams, the random forest model provided predictions that were much closer to the experimental results.

The rise of natural FRPs as ecological alternatives to synthetic ones has highlighted the need for studies on partial confinement using cotton ropes, which offer cost-effective, low-carbon solutions with high rupture strain. Unlike full confinement, partial confinement through cotton rope strips can efficiently strengthen deteriorated concrete sections with reduced material usage. Despite possessing several advantages, the partial confinement by cotton on concrete has not been investigated. This study addresses the gap by investigating the performance of cotton rope strips and developing analytical models to predict their structural impact. This study tested cylindrical concrete specimens of two strengths, strengthened with cotton rope in either complete wrapping (Group 1) or strip wrapping (Group 2). Each group was further divided by concrete strength and included one unstrengthened specimen, and three strengthened with one, two, or three layers of cotton rope. Experimental results revealed that cotton rope wraps effectively confined the concrete, enhancing load-bearing capacity and improving ultimate compressive strength by 9.97-152.10 % and ultimate strain by 188.00 % to 1488.89 %. The compressive stress vs. strain behavior exhibited an initial stiff elastic ascent followed by a parabolic transition. The second branch of the response, either ascending or descending, was significantly improved with an increased confinement ratio. Type-I failure was characterized by an ascending second branch in the compressive stress vs. strain curve, while Type-II failure exhibited a descending second branch. Four specimens demonstrated Type-I failure (L-2F, L-3F, H-3F, and L-3S), predominantly in full configurations and with lower unconfined compressive strength. The modulus of the second branch improved with an increased confinement ratio, transitioning from Type-II to Type- I failure near a ratio of approximately 0.50. Regression analysis provided equations of various key points along the compressive response with R2 values greater than 0.90, highlighting a strong dependence on the confinement ratio. The Popovics model effectively predicted the first part of the compressive response, with predicted curves closely matching experimental results.

This research aimed to strengthen heritage masonry buildings using fiber-reinforced paint (FRP) and evaluate seismic responses, including the Arias intensity scale, peak acceleration, peak displacement, lateral drift, and dissipated energy. In the numerical phase, the prototype model was studied using the Applied Element Method (AEM) and similitude law, resulting in a wellperforming scaled model with error percentages of approximately 5 % for element results and 4 % for spring results. This validated the model's accuracy, leading to its adoption for experimental work. The experimental phase involved shake table testing of the scaled models, revealing that the unreinforced model (URM) collapsed at run 44, whereas the FRP-retrofitted specimen collapsed at run 52. Cracks in the FRP-retrofitted specimen began at run 39, compared to run 10 in the URM, with the FRP-retrofitted specimen arch masonry roof remaining undamaged prior to collapse. The FRP-retrofitted specimen demonstrated superior seismic performance, with an Arias intensity scale 3.67 times higher, base shear over 400 % greater, and lateral drift 10.89 times higher than the URM, indicating its ability to resist significant displacement and deform plastically. Additionally, the FRP-retrofitted specimen exhibited stable, wider hysteretic loops, leading to 6.1 times more energy dissipation than the URM, thereby offering enhanced safety for occupants.

This study investigates the application of the Circular Economy (CE) principles in cement–sand mortar by partially replacing natural fine aggregates with recycled materials. The aim is to promote sustainable construction practices while reducing ther environmental impacts associated with sand mining and waste disposal. Three types of recycled aggregates were evaluated: Recycled Concrete Aggregate (RCA), Crushed Brick (CB) aggregates (CBA, CBB, CBC, CBD), and crumb Rubber Aggregates (RB10, RB20, RB40). Each replaced 15% of the sand content by mass for the mineral wastes and by volume for the rubber, across three water-to-cement (w/c) ratios: 0.4, 0.5, and 0.6. The workability was assessed using the flow test as illustrated in [17]. The results revealed that the mortars with RCA and brick aggregates exhibited low workability at lower w/c ratios due to the high water absorption and the rough particle textures of the aggregates. In contrast, Rubberized Mortars (RB) showed excellent flowability across all ratios, attributed to rubber’s non-absorptive nature. Increasing the w/c ratio improved the flow in all mixes, though the rubber aggregates consistently outperformed others. The findings highlight the feasibility of using recycled waste materials, particularly rubber, to produce workable, eco-friendly mortars, supporting the shift toward a more sustainable construction industry.