The water in concrete has to perform the following two functions:
(1) The water enters into chemical action with cement and this action causes the setting and hardening of concrete.
(2) The water-cement ratio for structures which are exposed to weather should be carefully decided. For instance, for structures which are regularly wetting and drying, the water-cement ratio by weight should be 0.45 and 0.55 for thin sections and mass concrete respectively. For structures which are continuously under water, the water-cement ratio by weight should be 0.55 and 0.65 for thin s