Underground anti-cracking and impermeable concrete with strength grade no more than C50 and preparation method thereof

The invention discloses underground anti-cracking and impermeable concrete with strength grade no more than C50. The underground anti-cracking and impermeable concrete is mainly prepared from a binding material, clastic rock, sand water and admixture, wherein the binding material is cement, mineral powder and coal ash; the admixture is a water reducer or an anti-cracking and impermeable agent and a water reducer. According to the underground anti-cracking and impermeable concrete prepared by the preparation method, green high-performance concrete is prepared from a lot of mineral powder and coal ashes in a compounding manner; the dosage of the cement for C30-C50 anti-cracking and impermeable concrete is reduced by 30-50% in comparison with that of common concrete, the production cost of the concrete is reduced, and the underground anti-cracking and impermeable concrete plays a protective role on the environment, and has significant economic benefits and social benefits.