ABSTRACT
Well-cured and compacted concretes of low to moderate water/cement ratio are generally capable of resisting chemical attack caused by acidic solutions because the rate of attack is usually very slow. However it is a reality that all of the main compounds produced following hydration may be dissolved by acids. Durability failure through contact with acids occurs by dissolution of the cement paste and certain aggregate types. The cement paste compounds affected include the calcium silicate hydrates, calcium hydroxide, tricalcium aluminate hydrate and ettringite. Concrete in contact with chemicals in a dry state are not usually affected but acid attack occurs if aggressive chemicals are in solution and contain acidic ions above a critical concentration level. The effect of dissolution may be manifested through surface erosion or complete disintegration of the concrete. Concrete in contact with flowing acids is more vulnerable than that in contact with static fluids.
