Specifications include, but are not limited to: 1.1 The aggregate must consist of gravel, crushed or uncrushed, crushed stone, sand-gravel, sand silt, or other approved materials having similar characteristics. 1.2 The aggregate must be free from lumps or balls or clay or other objectionable matter and must be durable and sound. The portion of the material retained on a No. 4 sieve must be known as coarse aggregate, and the materials passing a No. 4 sieve must be known as binder material. 1.3 Coarse aggregate conforming to the requirements specified must have a percentage of wear not to exceed fifty after five hundred revolutions, as determined by the American Association of State Highway and Transportation Officials (AASHTO) Standard Method T-96. 1.4 Binder materials must consist of sand silt, or other finely divided mineral matter obtained from sources approved by the Street Superintendent, or naturally combined with the coarse aggregate. Binder material must be free from vegetative or other objectionable matter. 1.5 The binder material either naturally combined with the coarse aggregate or separately obtained and mixed therewith, must be of such character that the composite material will conform to the gradation and other requirements specified. Care must be taken to insure that the kind of materials that is contained in that fraction passing the No. 200 sieve is not of a nature that will expand excessively when wet. 1.6 Gradation: The composite mixture of coarse aggregate and binder material, processed as specified below, must conform to the gradation shown in the following table. SIEVE DESIGNATION PERCENTAGES BY WEIGHT PASSING / SQUARE MESH SIEVES 1 – 1/8” 100 ¾” 70 – 100 3/8” 50 – 75 NO. 4 35 – 60 NO. 10 25 – 50 NO. 40 10 – 30 NO. 200 3 - 12
