The invention relates to the field of concrete, in particular to low-
magnetism low-hydration-heat concrete and a preparation method thereof. The concrete comprises the following raw materials: a cementing material, fine aggregate, coarse aggregate, water and a water
reducing agent, the cementing material comprises
cement and
slag powder, the
cement accounts for 60%-70%, and the
slag powder accounts for 30%-40%; the coarse aggregate adopts three-graded broken stone, the maximum particle size is 80 mm, the maximum value allowed by water transportation
engineering specifications is met, and the use amount of a cementing material is effectively reduced and can be reduced by about 15% compared with that of common C30 concrete; the reduction of the cementing material not only can reduce the cost of the concrete and bring remarkable
economic benefits, but also can reduce the hydration heat in the
mass concrete, and does not need to add a hydration heat inhibitor to reduce the
cracking risk of the concrete; the raw materials are detected by a
metal detector, so that the raw materials are prevented from being mixed with magnetic substances, the
slump of the concrete is 30-80mm, and the concrete is transported by adopting a hanging tank, a
belt conveyor, a dumper and the like, so that the construction is convenient.