This paper analyses the effect of mineral additives on alkali - silica reaction. Amorphous SiO2 contained in concrete aggregate is known for reactions with Na2O and K2O that cause concrete expansion and cracking. Concrete expansion is the result of silicates reaction (ASR). Alkali silica gel is a reaction product having expanding properties. Expanding silica gel creates stress that causes concrete cracking. The paper investigates the elimination of the negative effect of ASR by using fly ash as active mineral additive. In the tests active mineral additive (fly ash) is expected to reduce the effect of alkali - silica reaction and volumetric strain.
