Composite construction materials are widely utilized and have demonstrated superior efficiency compared to their constituent materials, such as steel and concrete. Despite their structural integrity and energy efficiency, reinforced concrete sandwich panels face limited adoption in numerous rural areas of developing countries like Pakistan, primarily due to the financial constraints of the population. Hence, this study proposes economical reinforced mud sandwich panels (RMSPs) incorporating mud wythes and investigates their flexure behavior. Mud being the commonly used construction material in rural areas, is readily available, making reinforced mud sandwich panels a potential viable alternative to conventional concrete sandwich panels. Three full-scale models of RMSPs were fabricated. The panels consist of an expanded polystyrene (EPS) layer reinforced with welded galvanized steel wires forming a mesh structure and shear connectors. In addition, both sides of the EPS were plastered with a layer of stabilized mud to create wythes of RMSPs. A stabilized mud mixture was prepared by combining constituents in the following proportions by weight: 67% soil, 10% cement, 1% wheat straw, and 22% water. All three RMSPs were tested under four-point loading. Two RMSP panels (RMSP-1 and RMSP-2) were tested by increasing the load gradually until failure. While the third panel (RMSP-3) was subjected to cyclic loading up to 7 kN, the load was then progressively increased till failure. According to the results obtained, the failure of the RMSPs occurred due to the EPS (core) fracture and crack propagation in the lower wythe under flexural stresses. Nonetheless, the panel resisted structural collapse despite experiencing significant midspan deformation. Numerical analysis of RMSP was also performed using finite element software (ABAQUS). The results demonstrated a strong correlation between numerical simulation and experimental results. RMSP exhibits promise as a potential alternative in sustainable construction technology, offering sufficient load-bearing capability and favorable structural properties such as ductility.

The use of both recycled coarse aggregates (RCAs) and recycled sand (RS) derived from weathered residual soil of granite (WRSG) into concrete has the potential to greatly enhance the recycling of construction and demolition waste. However, the characterization of RS from WRSG and the compressive and flexural performance in fresh concrete containing RCAs and RS have not been thoroughly investigated. In this study, clay content, fineness modulus, chemical compositions, mineral compositions, and pore structure of RS from WRSG were tested. On this basis, the optimized preparation parameters of RS were suggested. The compressive behavior, flexural behavior, and cement hydration degree of recycled aggregate concrete (RAC) simultaneously containing RS and RCAs were investigated comprehensively. A stereological model was proposed to explain the results related to cement hydration. The results showed that: (a) the optimized preparation could substantially lower the clay content of RS; (b) RS was more porous than natural sand (NS), resulting in a higher water absorption during mixing; (c) the compressive strength of concrete containing RS developed faster than the concrete with NS; (d) at day 90, the compressive and flexural strength of the concrete containing RS were not less than those of the concrete with NS; and (e) RS was shown to have a greater influence on the hydration degree of cement paste than RCAs, due to RS significantly reducing the average value of inter-aggregate spacing in concrete, making the cement paste more susceptible to the internal curing effect induced by the water in aggregate pores.