Evaluation Protocol for Concrete Aggregates Containing Iron Sulfide Minerals

Several cases of concrete deterioration involving sulfide-bearing aggregates have been reported over the years. However, no specific guidelines are currently available to enable making a precise decision on the deleterious potential of aggregates containing iron sulfide minerals. The aim of this paper is to provide an innovative assessment protocol to evaluate the potential deleterious effects of iron-sulfide-bearing aggregates prior to their use in concrete. The findings of this paper are based on tests developed within the past few years as part of a major research project. The protocol is divided into three major phases: 1) total sulfur content measurement; 2) oxygen consumption evaluation; and 3) an accelerated mortar bar expansion test. Tentative limits are proposed for each phase of the protocol, which still need to be validated through the testing of a wider range of aggregates.