A new accelerated testing scheme to evaluate the potential oxidation reaction of sulfide-bearing aggregates in concrete specimens.

The search for reliable tools to assess potential deleterious reactions in sulfide-bearing aggregates, is driven by recent field structure damage involving such types of aggregates. The paper presents a new test scheme with detailed procedures and limit criteria. Five aggregates, including pyrrhotite-bearing reactive ones (Connecticut and MSK 0.9), an alkali-silica reactive low-sulfur limestone (Spratt), a non-reactive control (PKA), and a low-sulfide aggregate (MSK 0.2), were used to manufacture concrete specimens that were subjected to the proposed test. The limit criterion, based on modulus of elasticity loss (RMoE), effectively distinguishes non-reactive, reactive, and potentially reactive aggregates. The scheme's reliability is validated against an existing protocol involving sulfur determination and mortar bar expansion testing. Four of five aggregates exhibit similar potential sulfide reactivity. Despite excessive mortar bar expansion, MSK 0.2, with traces of pyrrhotite, shows non-reactive behavior in concrete specimens after electrochemical treatment. The proposed test scheme offers a practical and timely tool for assessing sulfide-bearing aggregate reactivity before concrete production. [ABSTRACT FROM AUTHOR]