INVESTIGATION OF FACTORS INFLUENCING THE EXPANSIVE BEHAVIOR, COMPRESSIVE STRENGTH AND MODULUS OF RUPTURE OF ALKALI - SILICA REACTIVE CONCRETE USING LABORATORY CONCRETE MIXES

Alkali-silica reaction (ASR) in concrete results in expansion of the c oncrete and possibly severe cracking. The cracking leads to a reductio n in the compressive strength and the modulus of rupture of the concre te. A test programme is under way on model structural elements that ar e suffering from ASR. As a prelude to this, a series of ASR concrete m ixes were developed. This Paper examines the performance of these ASR mixes with respect to normal mires, and comments on factors that were found to influence their compressive strength, expansion and modulus o f rupture. Time-dependent variation in these factors is identified and assessed. The mixes used consisted of flint gravel, ordinary Portland cement, fused silica as a reactive aggregate and potassium hydroxide to increase the supply of alkalis in the mix. As well as the quantitie s of these materials, the particle size distribution of the fused sili ca was varied, as was the environment in which the concrete was cured and stored.