Steam Curing Influence on Fly Ash High-Performance Recycled Concrete

High-performance concrete (HPC) mixtures were produced using 100% coarse recycled concrete aggregates (RCAs) from three different qualities. The concretes were produced using two binders: portland cement and portland cement with 30% of fly ash. Moreover, the fly ash mixtures underwent two different curing methods: conventional and steam curing. The effects of RCA on the physical, mechanical, and durability properties of HPC were studied for the production of prestressed elements. The natural aggregates could be completely replaced by RCA sourced from the same quality HPC. It was determined that when using lower-quality aggregates, the use of fly ash produced low 1-day compressive strength, with the consequent necessity to use steam curing to fulfill the standard requirements to be used in the production of prestressed elements. The steam curing had negative effects on the long-term mechanical properties; however, these effects were attenuated by using RCAs, which maintained their great durability.