Volume 4, Issue 5 (September 1976)
Past, Present, and Potential Developments of Sulfate-Resisting Concretes
The relations between computed or measured C3A contents and sulfate deterioration of concrete and the modifying effects of C4AF on these relations are discussed. The poor performances of some high quality sulfate-resisting mortars and concretes and the anomalous effects of porosities of cement pastes are considered. Research indicates that the life expectancy of pozzolan concretes relates more to the kind of pozzolan than to limitations on amounts of C3A and C4AF of Types II and V cements. Future specifications should consider interrelations of pozzolan quality, W/C ratio, and rigorously defined porosity as primary factors in sulfate attack on concretes. Results showed that Type II and Type V cements used with the same pozzolans were equally effective in resisting sulfate attack. Present hypotheses on the effects of C4AF on sulfate attack or prevention of attack are not sufficiently developed for practical use.