Experimental Investigation on the Mechanical Performance of Nano-Silica Blended Cement Concrete Under Elevated Temperature Conditions

Abstract Concrete structures exposed to elevated temperatures experience significant deterioration in mechanical properties due to dehydration of hydration products and microstructural damage. In recent years, nano-silica has emerged as a promising cementitious additive capable of improving strength and microstructural integrity of concrete. This study presents an experimental investigation on the mechanical performance of nano-silica blended cement concrete subjected to elevated temperatures. Nano-silica was used as a partial replacement of cement at 0%, 1%, 2%, and 3% by weight. Concrete specimens were cured for 14, 28, and 56 days and subsequently exposed to elevated temperatures of 200°C, 400°C, and 600°C. Compressive strength and split tensile strength tests were conducted after natural cooling. The results indicate that nano- silica significantly enhances strength and improves residual performance at elevated temperatures, with optimum performance observed at 2% replacement. The study demonstrates that nano-silica blended concrete exhibits improved thermal resistance and can be effectively used in structures exposed to high-temperature conditions. Keywords: Nano-silica, elevated temperature, compressive strength, split tensile strength, residual strength, concrete.