Alkali-silica reaction is a prevalent type of deterioration in concrete infrastructure. In laboratory testing, prisms are cast horizontally and subsequently tested for expansion in the vertical direction. This may not adequately relate to actual cast-in-place concrete structures. In this research, prisms were cast in horizontal and vertical directions. Both axial and transverse expansions were measured. Spratt aggregate and fused silica were used to hasten reactions leading to a clear monitoring for the influence of fused silica and casting direction. Results showed that the vertical casting was seen to increase the measured expansion by about 5-8% depending on the age of measurements. Moreover, the higher the fused silica, the higher the expansion regardless of the casting direction.

Key Word: Fused Silica, Alkali-Silica Reaction, Concrete, Aggregate, Expansion