Aggregates

Abstract

Aggregates are granular materials used either as underlying materials for foundations and pavements or as skeleton structure and filling in Portland cement concrete and asphalt mixture. The physical properties, mechanical properties and gradation of aggregates have significant impacts on the performance of infrastructure. This chapter introduces the production, physical properties, mechanical properties and gradations of aggregates. The physical properties of aggregates include different densities, unit weight, void ratio, angularity, and fractured faces. The mechanical properties of coarse aggregates include crushing value, impact value, polished stone value, abrasion value, and soundness. The properties of fine aggregates mainly include different densities, unit weight, void ratio, angularity, fineness modulus and sand equivalency. By the end of the chapter, the sieve analysis, graduation curves, gradation theory and gradation designs methods are introduced.