Evaluation of Recycled Concrete as Aggregates in New Concrete Pavements

This study evaluated the use of recycled concrete as coarse aggregate in new concrete pavements. Recycled concrete aggregate (RCA) produced from demolished pavements in three geographically dispersed locations in Washington State was used to perform tests on aggregate characteristics, fresh concrete properties, and hardened concrete properties. Variables included the source of the RCA, percentage of replacement of coarse natural aggregate with RCA (0% to 45%), and percentage of replacement of portland cement with Class F fly ash (0% or 20%). RCA from all three sources met the Washington State Department of Transportation (DOT) requirements for aggregates, and all fresh and hardened concrete properties met Washington State DOT requirements. Replacement of RCA for natural coarse aggregate by up to 45% by volume had no significant effects on any of the concrete properties. These results indicate that high-quality RCA can be used as a replacement for a portion of the coarse natural aggregates in new portland cement concrete pavements.