Alkali Aggregate reaction in Dam Structures – a Review

Abstract

Alkali – Aggregate Reaction is an unwanted reaction which occurs in concrete, mainly the area which is subjected to more moisture content. It occurs over time, between cement paste and silica. This in turn alters the expansion of the aggregate and often in an unpredictable way, which will result in loss of strength of concrete and also a complete failure. Hydro structures, mainly Dams store water, presence of moisture can cause such problem, comparatively more than the other structures. Normally, most of the dams had been constructed several years back and they still exist. The design was based on the environmental conditions prevailed at that period. But now the fast changing environmental aspects and industrial growth and technological development apart from global warming has severe impact on the life and performance of the dams. Dam Structures cannot be easily replaced, and the swelling can block spillway gates or turbine operations. The durability of dams has the impact on human life, society and the environment. To enhance the life and durability of the dams or hydro structures, several studies were made. There are two forms of Alkali Aggregate Reactions available, Alkali Silica Reaction and Alkali Carbonate Reaction and this paper reviews Alkali Aggregate reaction within concrete construction.