Specifications include, but are not limited to: - This material shall consist of a natural or manufactured mixture of gravel and soil mortar uniformly well graded from coarse to fine and so proportioned as to meet all the requirements hereinafter specified. The aggregate shall consist of crushed or uncrushed hard gravel or crushed stone or a combination of crushed and uncrushed material. The material furnished shall not contain more than 15% by weight of shale, slate, and other objectionable, deleterious or other injurious matter. GRADING REQUIREMENTS Class D-8 Sieve Percent Passing 2" 100 3/4" 70 to 100 #4 35 to 65 #40 15 to 40 #200 3 to 30 GRADING REQUIREMENTS Class D-4 Sieve Percent Passing 2" 100 3/4" 60 to 95 #4 25 to 55 #40 10 to 35 #200 3 to 30 Maximum Plasticity Index 20