Specifications include, but are not limited to: Concrete must be a proportioned uniform mixture of graded fine and coarse aggregates and cementing material. The cementing material will be Portland Cement and water for cement concrete and bituminous cements for asphalt concrete. BIDDERS MUST SUBMIT MSDS OR OTHER DOCUMENTATION SHOWING THEIR PRODUCT MEETS THE DISTRICT’S SPECIFICATIONS. a. Portland Cement: It shall conform to the requirements of Specifications for Portland Cement, ASTM C150. Type I cement shall be used unless otherwise specified. b. Aggregates for Concrete: (a) They shall conform to the requirements of Specifications for Concrete Aggregates, ASTM C33, except as further specified herein. (b) Natural sand shall consist of clean, hard, durable, uncoated grains. Mississippi and Missouri river sands or other sands containing lignite are not acceptable for exposed concrete. Gravel shall be washed, hard, strong, durable pieces free from thin, porous, elongated, or laminated particles. Crushed limestone for coarse aggregate shall consist of uncoated particles of sound, durable rock of uniform quality, without an excess of flat, elongated, or laminated pieces. No surface, yellow, or soft stone shall be permitted. The specific gravity of the stone shall be not less than 2.56. c. Water: when used with cement in mortar or concrete or for curing of concrete, the water shall be potable.