Reactivity Assessment of Recycled Concrete Aggregates to Sulfate Attack.

The attached cement paste in recycled concrete (RC) aggregate leads to its potential reactivity against sulfate ions. Several test methods were evaluated to find a suitable, reliable, and accurate method to evaluate the potential reactivity of aggregates. Different quality RC aggregates were used to apply those methods. The studies included evaluations of concrete cores drilled from source concrete (SC), RC aggregates, recycled mortar bars under different exposures, and RC prisms exposed to external sulfate attack (ESA). The concrete core test allowed qualifying SC as potentially reactive against sulfate in a short time. Tests on recycled aggregates and recycled mortar bars showed variable sensitivity levels. Results from concrete prisms showed an effective reactivity of recycled aggregates when the replacement is higher. [ABSTRACT FROM AUTHOR]