2 Structural Material
Unless test or experience indicates that a
particular water source is satisfactory, water should be free from acids, alkalis, oils, and organic impurities. Inert filler material ( usually sand and stone or gravel) make up between 60 and 80 percent of the volume of normal concrete.
2 Structural Material
Recommended and typical mixes of concrete for
various type or classes of work will determine how to proportion concrete mix. Factors affecting this include: (1) water to cement ratio,(2) type and size of aggregate, (3) air of nonair-entrained concrete, and (4) slump of the mix.
2 Structural Material
Strength, durability and water tightness are
usually specified by the structural –design engineer, but a tentative mix proportion can be determined from knowledge of a prior job. As water is added, the plasticity and the fluidity of the mix increase (i.e., its workability improves), but the strength decreases because of the larger volume of voids created by the free water.
