Ultra-high performance concrete with micro-expansion and compensation shrinkage and preparation method thereof

Abstract

The invention belongs to the field of building materials, and especially relates to ultra-high performance concrete with micro-expansion and compensation shrinkage and a preparation method thereof. Raw materials include, by weight, the following components: 1 part of cement, 0.05-0.2 part of fly ash, 0.2-0.5 part of silica fume, 0.1-0.25 part of mineral powder, 0.05-0.2 part of quartz powder, 0.9-1.2 parts of quartz sand, 0.04-0.2 part of an expanding agent, 0.01-0.03 part of a water reducing agent, and 0.01-0.03 part of an expansion promotion reinforcing agent. A mixing amount of super absorbent resin is 0.4%-0.8% of a cementing material; a volume mixing amount of steel fiber is 1%-3% of a total volume of the concrete; the water-to-binder ratio is 0.16-0.22; and the compressive strength is 100-160 MPa. The ultra-high performance concrete with the micro-expansion and the compensation shrinkage has the characteristics of micro-expansion, high strength, high toughness, excellent workingperformance, and the like, and solves the problem that the expanding agent is difficult to produce effective expansion in the ultra-high performance concrete with a low water-to-binder ratio, and so,the risk of early shrinkage cracking of the ultra-high performance concrete is reduced, and the ultra-high performance concrete can maintain the micro-expansion for a long time.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to micro-expansion-compensated-shrinkage ultra-high-performance concrete and a preparation method thereof. Background technique [0002] Ultra-High Performance Concrete (UHPC for short) is a new type of cement-based composite material with higher strength, better toughness and better durability than ordinary concrete. It solves the requirements of structural engineering to develop towards higher height, larger span and heavier load, and at the same time adapts to the requirements of the development of the times, so that the performance of concrete has been greatly improved. It is the most creative in the past three decades. cement-based engineering materials. However, UHPC also has its own defects. Due to the low water-binder ratio and high cement content, UHPC under normal temperature curing is very different from ordinary concrete, that is, the shrinkage of...

AI Technical Summary

Problems solved by technology

Judging from the published UHPC-related literature, such as Influence of combination of expansive and shrinkage-reducing admixture onautogenous deformation and self-stress of silica fume high-performance concrete published in 2010, this literature uses anhydrous calcium sulfoaluminate expansion Although it can reduce the free shrinkage of HPC with a water-binder ratio of 0.23 to 60uε, it cannot fully compensate for the shrinkage to achieve micro-swelling; such as Shrinkage and cracking of restrained ultra-high-performance fiber-reinforced concrete slabs at earlyage published in 2014, This document uses anhydrous calcium sulfoaluminate expansion agent, although it can reduce shrinkage, it cannot fully compensate for shrinkage to achieve micro-swelling; such as The influence of expansive agent on the performance offer reinforced cement-based composites published in 2015, This document uses a calcium oxide expansion agent. Although it can reduce the free drying shrinkage of UHPC with a water-binder ratio of 0.19 to 120uε, it cannot fully compensate for the shrinkage to achieve micro-swelling.

Therefore, it can be seen that the shrinkage cracking problem of UHPC has not been solved yet.

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