Use of Aggregate Screenings as a Substitute for Silica Sand in Portland Cement Concrete (PCC)

摘要

The State of Florida is the third largest consumer of crushed rock products in the United States and is the largest single contractor/user of crushed stone resources in the state. Crushed stone in Florida is produced from limestone, which is mined or extracted from naturally occurring deposits. This crushing for coarse aggregate results in a fine byproduct called screenings. The stockpiling and disposal of fines produced as a result of aggregate crushing and production operations are some of the major problems facing the aggregate industry. This project investigated the use of these screenings as a substitute for natural sand in PCC. Influence of screenings was tested in the mortar and in concrete specimens for fresh and hardened state properties, including flow, strength and durability. It is concluded that the screenings can be used safely in blended form for projects where durability is not the main concern.