WORKABILITY AND COMPRESSIVE STRENGTH PROPERTIES OF CONCRETE CONTAINING RECYCLED CONCRETE AGGREGATE

Abstract

This paper describes two laboratory based experimental studies to determine some plastic and hardened properties of concrete incorporating recycled concrete aggregates. One study examined the effects that the cleanliness of recycled coarse aggregate particles has on the concrete properties, where cleanliness relates to the amount of cement paste and mortar adhering to the surface of the aggregate particle. The second study examines how the workability and compressive strength characteristics of concrete mixes are affected when varying amounts of recycled concrete fines are used as cement replacement. Experimental procedures for both studies involved the breaking and crushing of cast concrete blocks to produce recylced materials. Experimental results indicated that for concretes containing recyled coarse aggregates, as cleanliness of the recycled aggregate particles decreased, workability and compressive strength decreased, whereas air content increased. For concretes containing recycled fines, workability generally increased with lower replacement level, and decreased with higher, whereas compressive strength decreased for all levels of cement replacement. For the covering abstract see ITRD E112391.