Specifications include, but are not limited to: Type VI Classified Fill and Backfill shall consist of crushed gravel, rock, sand, or other approved material. The aggregate shall be free from lumps, balls of clay, or other objectionable matter, and shall be durable and sound. The portion of the material retained on a No. 4 sieve shall be known as coarse aggregate. Both coarse and fine aggregates shall conform to the quality requirements of AASHTO M-147. It shall have a plasticity index not greater than six (6) as determined by ASTM D-424. U.S. STD. Sieve Size 2" llh" %" 12" No. 4 No. 10 No. 40 No. 200 Coarse Aggregate Cumulative Percent Passing by Weight 100 65-95 50-80 30-60 20-50 10-30 05-25 02-06 The coarse aggregate material conforming to the requirements specified above shall have a percentage of wear not-to-exceed 50 after 500 revolutions, as determined by the current requirements of ASTM C-131. It shall consist of angular fragments reasonably uniform in density and quality, and reasonably free from thin and elongated pieces, dirt and other objectionable material.