Journal of Building Material Science

Washout and Strength Behaviors of Underwater Concrete Containing Welan Gum and Slump Retainers

2026-07-09T15:02:53+08:00

This study explores the synergistic effects of welan gum-based anti-washout admixtures (AWAs) and slump-retaining polycarboxylate ether superplasticizers (SK-PCEs) in underwater concrete (UWC). It addresses the inherent challenge of simultaneously achieving sufficient viscosity to resist washout while maintaining adequate workability for extended placement. Three mortar series incorporating different water-to-binder (w/b) ratios and AWA/SK-PCE combinations were investigated through tests of time-dependent flow behavior, washout resistance, V-funnel flow time, bleeding, setting time, and compressive strength. Test results showed that the incorporation of SK-PCE is efficient to reduce the rate of flow loss over time, yet without altering the V-funnel flow time (i.e., viscosity) measurements. At a high w/b of 0.5, the AWA's ability to trap mixing water (bleeding) and reduce washout loss was slightly disrupted by the SK-PCE. However, at lower w/b of 0.42 and 0.36, the negative SK-PCE impact becomes negligible, suggesting that the inherent particle packing and naturally cohesive mixtures compensate for the dispersive energy provided by the PCE polymers. While the incorporation of AWA prolonged setting and reduced late-age compressive strength, the addition of SK-PCE alongside AWA had a neutral effect. From a practical standpoint, this reflects the possibility of adjusting the AWA and SK-PCE couple in order to optimize washout resistance and workability drop without dramatically compromising the setting and durability of UWC mixtures.

Experimental Investigations on Reinforced Concrete Gable Beams Strengthened with CFRP Sheets

2026-06-11T16:14:52+08:00

This study presents an experimental investigation on the structural performance of reinforced concrete (RC) gable beams strengthened with carbon fiber reinforced polymer (CFRP) sheets. A total of six RC gable beams were cast and tested under static loading applied at mid-span. One specimen served as a solid control beam, while two unstrengthened specimens incorporated eight circular or trapezoidal openings to reduce self-weight. The remaining three specimens featured identical geometries but were strengthened using CFRP sheets to enhance their bending and shear resistance. Evaluated parameters included load-deflection curves, ultimate load capacities, cracking patterns, failure modes, and structural strains. This research addresses a critical gap regarding the structural behavior and CFRP strengthening of perforated RC gable beams. Results demonstrated that incorporating openings successfully decreased beam self-weight by 14%, though inducing a minor 6.25% reduction in ultimate capacity. However, CFRP configurations significantly improved the load-carrying capacity by approximately 35% and substantially delayed crack propagation. Specifically, CFRP sheets delayed the first crack appearance, increasing its associated load by up to 82.35% when comparing the gable beam strengthening with CFRP sheets (GBS) specimen with the control gable beam (GB) specimen. Furthermore, the strengthening technique efficiently minimized concrete and steel strains across all specimens, reducing maximum concrete strain by 33.3%. Ultimately, the findings confirm that CFRP strengthening is highly efficient in eliminating the adverse structural effects of weight-reducing openings, ensuring structural integrity.

Evaluation of CMU Shear Walls Using Digital Image Correlation

2026-05-04T13:52:03+08:00

Throughout recorded history, masonry has played a significant role in the construction of structures across diverse cultures and geographic regions. In the last century, concrete masonry units (CMU) have effectively replaced traditional red brick in masonry in the US with the exception of some veneer purposes. CMU structures are significantly stronger than traditional masonry and have a wide variety of uses, with walls being the most common application. The research presented here investigates the differences in failure behavior of CMU shear walls with varying horizontal joint reinforcement configurations. Existing literature acknowledges that horizontal joint reinforcement is key to shear strength in masonry walls, but no research was identified that experimentally tests shear walls with spliced joint reinforcement. Two CMU walls were tested in quasi-static unidirectional lateral pushover, one with continuous joint reinforcement and one with spliced joint reinforcement. To evaluate specimen behavior, digital image correlation (DIC) was utilized as the primary measurement tool, revealing previously unobserved aspects of cracking patterns and their relationship to reinforcement splice regions. Analysis of the test results showed that walls containing uninterrupted joint reinforcement were capable of sustaining larger maximum loads and maintained a more ductile response after reaching peak capacity. Additionally, the presence of reinforcement splices was associated with elevated strain measurements occurring at numerous locations within the wall system.

Digital Traceability and Lifecycle Performance of Bamboo-Based Construction Materials: Enhancing Durability and Circular Reuse through Smart Monitoring

2026-01-13T10:06:58+08:00

This paper explores the role that traceability and the use of predictive analytics could play in improving the durability and reusability of bamboo-based building materials. In an effort to better understand the problem being solved, a web-based monitoring platform has been developed across bamboo building projects in Jordan leveraging the use of Internet of Things (IoT) technology, machine learning modelling algorithms, and a web-based dashboard. The data generated from the installed sensors was modelled using algorithms such as the Random Forest algorithm and the XG Boost algorithm. Additionally, interviews were done. Analysis revealed improved durability in the digitally traceable bamboo parts compared to the manually inspected parts through the increased residual strength of 9–12% and a life span of about three months. Introduction of environmental factors enabled the life span recalibration in the digital-twin system (R² = 0.89) compared to the previous predictions. Reuse circularity in the digital-twin platform improved as 62% of the components were categorized as high-reuse components. A combination of predictive intelligence and environmental analysis describes a replicable approach for the sustainable management of building materials in data-driven construction environments.

Experimental Assessment of Reinforced Concrete Incorporating Waste Tile Powder and Metakaolin under Aggressive Environmental Conditions

2026-06-26T12:00:14+08:00

Concrete deterioration in aggressive environments poses significant challenges for the durability of reinforced concrete structures. The incorporation of supplementary cementitious materials offers a promising strategy to enhance performance while reducing cement consumption. This experimental study investigates the effects of metakaolin and waste ceramic tile powder as partial cement replacements on the compressive and flexural behavior of reinforced concrete members exposed to aggressive environmental conditions. Ten concrete mix designs were prepared with replacement levels of 10%, 20%, and 30% using metakaolin and waste tile powder. A total of 120 concrete cubes (100 mm) and 56 reinforced concrete slabs (40 × 200 × 600 mm) were cast and subjected to both standard curing and aggressive exposure regimes, including continuous immersion and alternating wet–dry cycles. The results demonstrate that the pozzolanic activity of metakaolin became more pronounced after 3–6 months, leading to enhanced mechanical performance. All mixtures containing waste tile powder exhibited higher compressive strength than the control mix. An increase of up to 11% in flexural capacity was observed for slabs incorporating 20% metakaolin, while slabs with 30% waste tile powder achieved an 8% improvement compared to lower replacement levels. Notably, specimens with 30% waste tile powder showed a significant increase in the experimental-to-nominal flexural capacity ratio, reaching values of 1.57 and 1.50 at 90 and 180 days, respectively. Overall, the combined use of metakaolin and waste tile powder improved durability and structural performance under aggressive conditions, indicating their potential for sustainable construction and rehabilitation of reinforced concrete structures.

Optimization of the Mechanical Properties of Epoxy–Palm Fiber Composites Using a Simplex Experimental Design

2026-06-24T17:28:04+08:00

This article presents a study on the development of environmentally friendly materials. In the current context of environmental preservation, facing climate change and the search for material solutions, the development of ecological materials has become essential. Composites reinforced with natural fibers offer a sustainable alternative to synthetic materials. Among these fibers, palm fibers stand out for their low cost, lightness, and abundance. Derived from agricultural waste, they contribute to the valorization of local resources while reducing environmental impact. Their use promotes the development of high-performance and ecological composites. The objective of this study was to develop epoxy matrix composites reinforced with palm fibers. A simplex experimental design was used to vary the fiber concentration from 5% to 20%, while maintaining a constant resin/hardener ratio. The physical and mechanical properties were evaluated by tensile tests, viscosity analysis, and density measurements. The results indicate a continuous improvement in stiffness, with the Young's modulus increasing from 2 GPa to 3.67 GPa when the fiber content reached 20%. Tensile strength reached a maximum value of 62 MPa at a fiber content of 15%, before decreasing, suggesting an optimal concentration. This study confirms that palm fibers can serve as durable and effective reinforcements for optimized composite designs.

Investigation into the Corrosion-Resistant Properties of Psidium guajava Leaf Extract on Mild Steel in Simulated Conditions

2026-02-11T14:23:25+08:00

Plant-extract inhibitors are attractive for mitigating marine and oil-and-gas corrosion while reducing toxicity and environmental persistence. Here, an aqueous Psidium guajava (guava) leaf extract was evaluated as a green inhibitor for mild steel in 5% NaCl at room temperature for 24 h, under both (i) conditions without H₂S and (ii) H₂S-souring simulated by in situ Na₂S/acetic acid. Inhibition performance was pre-screened by the weight-loss method and interpreted using adsorption-isotherm fitting and Hill-type dose-response analysis to estimate apparent adsorption/thermodynamic parameters and characteristic concentrations. To assess environmental compatibility, bioaccumulation potential (log P_{o/w}), seawater biodegradation (OECD 306 BOD/COD), and a brine-shrimp toxicity screen were also assessed. The extract produced concentration-dependent inhibition with different optimum ranges depending on H₂S presence and exhibited low bioaccumulation potential and substantial biodegradation in the screening tests. Although electrochemical and surface-analytical validation is required, the combined corrosion-performance plus environmental-screening workflow suggests Psidium guajava leaf extract as a promising candidate for further development of sustainable corrosion inhibitors.