Sand and gravel shall be screened, graded and washed
free from injurious amounts of clay, loam and dirt. Sand shall be
sharp, course, natural sand. Gravel shall be crushed gravel or broken
stone having a maximum size of one inch. All aggregates shall comply
with ASTM C 33. Cement shall be Type IA or IIA air-entraining Portland
cement complying with ASTM C 175. Ready-mix concrete may incorporate
Type I or Type II Portland cement complying with ASTM C 150, with
an air-entraining mixture complying with ASTM C 260. Mixing water
shall be suitable to drink.