Supplementary Cementitious Materials Reactivity: From Model Systems to Concrete

Abstract

Newly developed reactivity tests for supplementary cementitious materials have shown the ability to quantify reactivity and to differentiate reactive and inert materials. Recent results using the modified R3 test are summarized here. The test uses a model system of supplementary cementitious materials mixed with calcium hydroxide in a simulated pore solution at 50 ℃. Heat release and calcium hydroxide consumption of the supplementary cementitious materials are measured. The reactivity of a large number of conventional and alternative materials has been measured using this test. By using both heat release and calcium hydroxide consumption, two measures of reactivity are obtained, and the test is able to differentiate pozzolanic, latent hydraulic, and inert materials. While the measured reactivity correlates with the properties of cementitious pastes, other factors including the supplementary cementitious material replacement level and the age of testing also influence these predictions. Thoughts on the use of reactivity testing to predict concrete durability are presented.