Classification and Production of Recycled Concrete Aggregates Based on Concrete

Completion Date: June 2022

Funding Agency: U.S. Army Corps of Engineers

Abstract: Recycled concrete aggregates (RCA) are produced by crushing hardened
concrete. The purpose of this study is to determine the mechanical and durability properties of
concrete with 100% recycled concrete coarse aggregates and relate the mechanical and
durability of new concrete to the physical, mechanical, and durability properties of RCA and the
RCA parent concrete. Parent concrete containing dolomite, granite, or limestone natural
aggregates mixed with water-to-cement ratios of 0.38 or 0.48 were crushed to create control
RCA. In addition, commercially available RCAs (unknown parent concrete(s)) were collected
from around the USA. The 28-day compressive strength of concrete made with RCA is
influenced by the water-to-cement ratio of the new concrete, the nominal maximum aggregate
size, specific gravity, and dry-rodded unit weight of the RCA, and the fresh concrete mixture
temperature and slump.

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