This paper presents two studies on sulfate resistance. One is destined to predict sulfate performance of blended cements. The Koch & Steinegger method and a polynomial equation to model evolution of test-parameter were used. A new criterion of evaluation, crack-time, is proposed. The other one, on the effect of pozzolan addition, establishes the relation between flexural strength development and sulfate resistance of these cements. Forty-one mortars containing different cement types and pozzolans or slag are computed and analyzed. Results show that the performance of blended cements can be predicted with 77 days of test-duration, but for high sulfate resistance blended cements 180 days are needed. Crack stress in sulfate environment is related to mechanical strength of mortar and crack-time depends on mortar capacity to develop tensile strength. © 1990.
