High-flexibility and low-shrinkage fiber reinforced cement-based composite material

Abstract

The invention belongs to the technical field of building materials, and in particular relates to a high-flexibility and low-shrinkage fiber reinforced cement-based composite material. The composite material is prepared by mixing cement, coal ash, silicon powder, gypsum, an expanding agent, a water reducing agent, a shrinkage reducing agent, a defoaming agent, a thickening agent, fine sand, fibers and water, wherein the total mass percentage of the cement, the coal ash, the silicon powder, the gypsum, the expanding agent, the water reducing agent, the shrinkage reducing agent, the defoaming agent, the thickening agent, the fine sand and the fibers is 77-85 percent, and the mass percentage of the water is 15-23 percent. The fiber reinforced cement-based composite material has the performance characteristics of low shrinkage, high flexibility, small crack width, quickness in condensation and early strength and is high in compressive strength and good in synergism with other materials.

Description

technical field [0001] The invention belongs to the technical field of building materials, in particular to a fiber-reinforced cement-based composite material with high toughness and low drying shrinkage. Background technique [0002] Concrete is a typical brittle material. After the load reaches the peak load, its bearing capacity drops sharply, and the deformation occurs concentratedly at the initial crack. Therefore, cracks appear in ordinary concrete structures after the stress exceeds the tensile strength of the concrete. To balance the deformation required by mechanical and environmental loads, the crack width will expand to a macroscopically visible level. Cracking not only reduces the load-bearing capacity of the structure, but also allows moisture and harmful chemicals to penetrate the protective layer and directly contact the steel reinforcement, which eventually leads to a reduction in the durability of the structure. [0003] To solve the long-term durability o...

AI Technical Summary

Problems solved by technology

[0004] High-ductility fiber-reinforced cement-based composites have relatively large defects, that is, the drying shrinkage of the base material is too large (drying shrinkage reaches 1500-2000 microstrain in 28 days)

Although the crack width is controlled after cracking, due to excessive dry shrinkage of the material, the risk of cracking increases, and the co-workability with other materials is significantly worse (the 28-day dry shrinkage strain of ordinary concrete is usually 400-800 microstrain)