Assessing the mechanical properties of concrete due to alkali silica reaction

The aim of this paper is to examine and validate the mechanical properties of concrete damaged by Alkali Silica Reaction (ASR). ASR was initiated by using fused silica as a reactive aggregate and increasing the alkali level of the concrete. The concrete was stored under controlled environment of 38°C and 100% RH for a period of one year. Over this time period, the strength of ASR concrete decreased by 40%, and the modulus of elasticity and modulus of rupture by 77% from their initial values. The expansion of the ASR concrete affects its mechanical properties which deteriorate as the concrete expands, and stabilised when the concrete ceases to expand. The initial properties of ASR concrete were validated by examining separately the effect of individual ASR-inducing parameters on the properties of normal concrete. It was confirmed that adding alkali in the normal concrete mixture reduces the initial strength of the concrete, but it increases the modulus of elasticity. Fused silica did not affect the initial strength of normal concrete, but the modulus of elasticity was affected by the amount of fused silica present in the concrete. Neither fused silica nor additional alkali affects the modulus of rupture of the normal concrete.