Earthen construction materials are increasingly considered a sustainable alternative for low-carbon housing due to their low embodied energy and environmental compatibility. However, their broader application is often limited by insufficient mechanical strength, poor water resistance, and relatively high self-weight. Despite the potential of bio-based stabilizers, the combined use of sawdust and cassava starch for simultaneously improving these properties in sandy soil remains insufficiently investigated, particularly for earthen housing applications. This study investigates the combined use of sawdust and cassava starch to improve the mechanical properties and water resistance of sandy soil for housing construction. A series of experimental tests was conducted, including unconfined compressive strength tests, splitting tensile strength tests, and water resistance evaluations through wet compressive strength, 5-mm immersion, and dry strength recovery after soaking. Microstructural analyses were further performed to clarify the stabilization mechanisms. The results show that the optimized mixture increased the compressive strength by 128
The increasing generation of industrial and construction-related waste, particularly limestone powder and construction and demolition waste (CDW), poses significant environmental challenges through landfilling, resource depletion, and increased carbon emissions. Simultaneously, the construction industry relies heavily on virgin materials such as cement and natural aggregates, whose production contributes substantially to global CO₂ emissions. This study investigates the feasibility of utilizing limestone powder, CDW, and coconut fibers as sustainable alternative materials in low-carbon concrete to reduce environmental impact while maintaining structural performance. Cement was partially replaced with limestone powder, natural fine aggregates were substituted with CDW, and coconut fibers were incorporated as reinforcement. The performance of the developed mixtures was evaluated through hardened property tests, thermal performance using infrared (IR) thermography, and mass loss measurements. Furthermore, Response Surface Methodology (RSM) was employed to analyze the interaction effects of the constituent materials and to optimize the mixture proportions through contour and three-dimensional response surface plots. The results indicated that replacing up to 10
Reusing industrial and agricultural by-products for soil stabilization offers a sustainable route to improving problematic soils and managing waste. This study evaluates fly ash (FA) and sugarcane bagasse ash (SCBA) as stabilizing agents for expansive clay (EC) considered for landfill hydraulic barriers. Sixteen mixtures across FA-EC, SCBA-EC, and FA-SCBA-EC series were tested for consistency limits, free swell index, compaction, ultrasonic pulse velocity, unconfined compressive strength (UCS), and hydraulic conductivity (HC). The addition of FA and SCBA substantially reduced plasticity and swelling potential through cation exchange, flocculation-agglomeration, and pozzolanic reactions, evidenced by elemental mapping, with FA-SCBA blends showing the greatest plasticity reduction ( 33.50
Shear failure in exterior beam-column joints (BCJs) remains a critical concern in structural engineering. Because the joint region contains highly congested reinforcement, concrete placement and consolidation are difficult. High-Volume Fly Ash Self-Compacting Concrete (HVFA-SCC) offers a sustainable solution because it is very easy to place, but its aggregate interlock capacity is low, which reduces shear strength at joints. Previous studies have primarily investigated diagonal bars in beam–column joints constructed with normal concrete, whereas experimental evidence regarding the cyclic behavior of HVFA-SCC beam–column joints reinforced with internal diagonal bars remains limited. The novelty of this study lies in experimentally demonstrating that diagonal bars compensate for the reduced aggregate interlock in HVFA-SCC by providing an alternative mechanism for joint shear-force transfer. Twelve large-scale exterior BCJs were tested under quasi-static cyclic loading in accordance with ACI 374.1–05. The specimens had three reinforcement configurations: no transverse reinforcement, standard transverse reinforcement, and diagonal bars within the joint core. The result (28 days) shows that HVFA-SCC without diagonal bars performed slightly worse than NC. Adding diagonal bars increased load-carrying capacity and energy dissipation by 30
Natural rock powders represent a promising category of supplementary cementitious materials (SCMs). While quartz monzonite powder (QMP) has received limited attention as an SCM, basalt powder (BP) has been more extensively studied; however, their combined incorporation in concrete remains largely unexplored in the existing literature. This study addresses these gaps through a comprehensive two-phase experimental program investigating QMP and BP as partial cement replacements at substitution levels of 3
