Ultra-high performance concrete with low shrinkage and low cement consumption

Abstract

The invention discloses ultra-high performance concrete with low shrinkage and low cement consumption. The concrete comprises standard cement, silica fume, superfine quartz powder, copper-plated straight steel fibers, a polycarboxylate superplasticizer, a cementing material, sintered bauxite aggregate and sand; the minimum limit value of the standard cement is 650 kg / m<3>, the content of the silica fume is 130 to 200 kg / m<3>, the mixing amount of the superfine quartz powder is 150 to 200 kg / m<3>, the volume mixing amount of the copper-plated straight steel fibers is 1.5% to 2%, the mixing amount of the polycarboxylate superplasticizer is 1% to 1.2% of the mass of the cementing material, the using amount of the sintered bauxite aggregate is 300 to 400 kg / m<3>, and the using amount of the sand is obtained by subtracting the amounts of other materials through an absolute volumetric method. According to the invention, the sintered bauxite aggregate is porous and can absorb water, so that an internal curing effect can be provided in various states, the strength of the concrete is improved, the use amount of cement is reduced, the problem of large shrinkage deformation of the traditionalUHPC is effectively solved, and the cracking risk of a structure or a component is reduced.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to the selection of curing medium materials in concrete, in particular to an ultra-high-performance concrete with low shrinkage and low cement consumption. Background technique [0002] Ultra-high performance concrete (UHPC) has ultra-high compressive and tensile strength, high toughness and excellent durability. However, because UHPC has the characteristics of low water-to-cement ratio, large amount of cementitious materials, and no coarse aggregate, the autogenous shrinkage caused by cement hydration in the early stage is relatively large, and the risk of cracking increases. If it is not handled properly, shrinkage cracking may be induced, thus affecting Safety and durability of concrete structures. The amount of traditional UHPC cement is relatively large, which can be 800-1000kg / m 3 , resulting in a large amount of total cementitious material, in the ran...

AI Technical Summary

Problems solved by technology

However, there are few reports on the use of sintered bauxite aggregate as the internal curing medium of UHPC at home and abroad.

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