Evaluating Alkali-Silica Reactivity for Concrete with Recycled Coarse Aggregate Using Concrete Prism and Autoclaved Concrete Prism Test Methods

ABSTRACT Reusing concrete from demolition work has the potential to produce sustainable concrete by replacing coarse aggregate with recycled concrete aggregate (RCA). A potential concern is the alkali-silica reaction in the parent source of concrete. This study presents experimental results that indicate using RCA with nonreactive natural aggregates in applications beyond base fill in roads has the potential to decrease the reactivity of the concrete. For example, expansions in concrete with RCA substituted for coarse aggregate were reduced to less than half of the expansion of concrete using the parent aggregate when tested using the concrete prism test (CPT). Furthermore, an autoclave concrete prism test (ACPT) with varying levels of RCA coarse aggregate replacement was conducted. In addition, both intralaboratory and interlaboratory precision statements were determined for 20 % and 50 % RCA replacements for nonreactive natural aggregates by conducting CPT tests with three operators in a single laboratory and ACPT tests in seven different laboratories. Results confirmed that using RCA in CPT and ACPT tests has precision limits within the allowable guidelines set by the ASTM standard for the CPT, indicating that RCA could be used in this test method without changing the precision limits.