CTB Specifications 1. The CTB mix will include Portland Cement, Type 1. 2. The stone aggregate will be TDOT 903.15 Red Clay Gravel or an acceptable EQUAL. The percentage of material passing the #200 sieve must exceed 12% for moisture retention. 3. The material must be water potable. 4. The material must have a 7-day compressive strength of 500 PSA, with a minimum cement content of not less than 10% by dry weight. Other Requirements 1. The plant providing the CTB must be equipped with a scale or scales, capable of weighing cement and aggregate in correct proportions during the mixing process. 2. The plant providing the CTB must have feeders or feeding devices capable of proportioning cement and aggregate consistently in the mixing process. 3. The Vendor supplying the CTB must have an onsite laboratory that meets TDOT specification 106.66 Type A, and that is capable of performing compressive strength and gradation tests. 4. Upon request, the selected Vendor must provide the periodic testing results to the City of Germantown.
