For structures which are regularly wetting and drying, the water cement ratio by weight should be ______ and _________ for thin section respectively.
A. 0.55, 0.45
B. 0.45, 0.55
C. 0.55, 0.65
D. 0.65, 0.55
Answer: b
Explanation: The water cement ratio for structure which are exposed to weather should be carefully decided. For structures that are continuously underwater, the water cement ratio by which should be 0.55 and 0.65 for thin sections and mass concrete respectively.