Effect of recycled brick sand on mechanical and transfer properties of roller compacted concrete “RCC” used for dams

ABSTRACT

This study explores the impact of incorporating recycled brick sand as a partial replacement for natural sand on the mechanical and transport properties of roller-compacted concrete (RCC) for dam construction. RCC mixtures were prepared with varying brick sand replacement levels and two different water/cement (W/C) ratios with cement dosages. Workability was assessed using the Vebe apparatus, while compressive and tensile strengths were evaluated at different ages. Additionally, porosity, water permeability, capillary absorption, and thermal conductivity were measured over time. Microstructural was characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The results indicate that brick sand has minimal influence on the RCC Vebe time. Compressive strength improves with brick sand incorporation, particularly in the long term, with an optimal substitution level of 25%. However, porosity and sorptivity increase at higher replacement levels, negatively affecting durability. Water permeability and thermal conductivity decrease with greater brick sand content, enhancing RCC’s resistance to fluid penetration and thermal properties. Variations in cement dosage and W/C ratio had a limited impact on the brick sand RCC performance. These findings suggest that partial replacement of natural sand with brick sand can enhance RCC properties while promoting sustainable material reuse in dam construction.

Keywords:
Recycled brick sand; Roller Compacted Concrete; Tensile strength; Compressive strength; Thermal conductivity