Coarse aggregate is used to describe particles larger than mm, and the term fine aggregate is used for particles smaller than Fine aggregates contain particles in the size range 75 µm to mm, and coarse aggregates from to about 40 mm, except for mass concrete which may contain particles up to 150 mm.
Overview. The Los Angeles () abrasion test (Figure 1) is a common test method used to indicate aggregate toughness and abrasion characteristics. Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing, degradation and disintegration in order to produce a high quality HMA.. Figure 1: abrasion testing equipment.