Ground limestone powder full-manufactured sand high-strength recycled self-compacting concrete and application thereof

Abstract

The invention discloses ground limestone powder full-manufactured sand high-strength recycled self-compacting concrete and application thereof. Per cubic meter of concrete contains 360-402kg of cement, 39-85kg of mineral powder, 45-88kg of fly ash, 70-96kg of ground limestone powder, 730-810kg of manufactured sand, 460-640kg of natural coarse aggregate, 300-400kg of recycled coarse aggregate, 10.3-13.7kg of polycarboxylate superplasticizer and 160-176kg of water. According to the full-manufactured sand high-strength recycled aggregate self-compacting concrete prepared from three additives including the ground limestone powder, the fly ash and the mineral powder, the fine aggregate is totally manufactured sand, and 31-46% of recycled coarse aggregate is added to the coarse aggregate, so that an effective path is provided for reducing exploitation and utilization of natural sand and sufficiently recycling concrete wastes, and a technical reference is provided for preparing the ground limestone powder full-manufactured sand self-compacting concrete.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a high-strength regenerated self-compacting concrete made of finely ground limestone powder whole machine-made sand and its application. Background technique [0002] With the development of the construction industry, more high-rise buildings with thin-walled structures continue to appear, which put forward higher requirements for concrete, because ordinary concrete can no longer meet its requirements. Therefore, self-compacting concrete came into being. However, the research on self-compacting concrete in China started late, and there are still few engineering applications at present. [0003] Self-compacting concrete requires high fluidity and requires no bleeding or segregation. Therefore, the aggregate requirements for the preparation of self-compacting concrete are relatively high. On the one hand, the use of river sand or mixed sand with few edges and corner...

AI Technical Summary

Problems solved by technology

[0011] To sum up, when preparing high-strength self-compacting concrete in the prior art, it has been reported that 100% machine-made sand is used as the fine aggregate, and natural stone is used as the coarse aggregate; expensive silica fume is often used in the admixture Or fly ash microbeads, some also use limestone powder, but the particle size is larger (not more than 100 mesh)

Disadvantages are: high price, low strength (only C50)

[0013] 1. High-strength self-compacting concrete requires high fluidity and strength, and the machine-made sand has many edges and corners and poor gradation, which greatly reduces the fluidity of the concrete mixture;

[0014] 2. The existing cement, slag powder and ordinary fly ash have poor particle shape, which also has a negative impact on the performance of concrete;

[0015] 3. The current admixture (silica fume or fly ash microbeads) is expensive; especially silica fume, which has a small particle size and light weight. When it is used to prepare concrete, the shrinkage is serious. In addition, it is mostly artificially added during production. When inhaled by the human body for a long time, it will cause damage to the lungs of the body;

[0016] 4. The stone powder used in the existing preparation of fully machine-made sand self-compacting concrete has a mesh size of 100 mesh, and the particles are relatively coarse. Most of the limestone powder particles can only be filled between the aggregate and the cementitious material, and the hydration effect is not high.

[0017] Therefore, it is difficult to meet the ideal requirements for fluidity, strength and economy of high-strength self-compacting concrete prepared with fully machine-made sand in the prior art

Images