Mechanical Properties of High-Strength High-Performance Reinforced Concrete Shaft Lining Structures in Deep Freezing Wells

Table 5

Coefficient of variation of concrete strength (%) [25].

Strength grade	C15	C20	C25	C30	C35	C40	C45	C50	C55	C60–C80
	23.3	20.6	18.9	17.2	16.4	15.6	15.6	14.9	14.9	14.1