Mechanical behavior of high-strength concrete incorporating seashell powder at elevated temperatures

Abstract

Cement-based composites may experience higher temperatures during their service period due to fire. After fire exposure, the concrete properties may be significantly affected in terms of safety and serviceability. Therefore, to improve the fire resistance of high-strength concrete, it was proposed to add seashells in cementitious composites for improved fire resistance. In this study, the seashell powder was used for concrete (0, 10, 20, and 30%) and plastering mortar (20%, 40%, and 60%) as a replacement of fine aggregate to develop high-strength concrete (HSC). Different properties, such as compressive strength, stress-strain response, elastic modulus, compressive toughness, strain ductility, mass loss of modified and controlled samples, and the deterioration caused by elevated temperatures exposure, were determined. The analyzed formulations were heated to a temperature of 200 °C, 400 °C, 600 °C, and 800 °C at a heating rate of 5 °C/min and then tested for residual conditions. Seashell modified samples showed a higher compressive strength, elastic modulus, and compressive toughness than the control sample at elevated temperature with less spalling sensitivity. According to visual inspection, SS-HSC, compared to HSC, showed less cracking at higher temperatures. Moreover, plastering high-strength concrete with seashell showed greater strength with more fire resistance to the concrete core. Conclusively, the utilization of seashells in high-strength concrete is efficient for fire-resistant concrete.