Internal curing sand for special concrete as well as preparation method and application thereof

Abstract

The invention discloses internal curing sand for special concrete as well as a preparation method and application of the internal curing sand. The internal curing sand is a core-shell inorganic spherical particle, the particle size of the internal curing sand is 1.0-6.0 mm, the wet bulk density of the internal curing sand in a saturated surface dry state is 800-1200 kg / m <3>, the cylinder compressive strength of the internal curing sand is greater than 6.0 MPa, and the water absorption rate of the internal curing sand is greater than 20%. The internal curing sand is prepared from waste materials, and is small in particle size, high in strength, large in stacking density and high in water absorption rate. The mixing amount of the internal curing sand in special concrete accounts for 10-30%of the use amount of a cementing material, and the internal curing sand can improve workability, reduce bleeding rate, improve pumpability, promote hydration of cement in concrete, significantly reduce self-shrinkage of high-strength concrete, improve expansion rate of expansive concrete, obviously improve crack resistance of the concrete and improve middle and later strength of the concrete. Theinternal curing sand of the invention is especially used for high-strength and ultrahigh-strength concrete, expansive concrete, fair-faced concrete and special structural concrete which is difficult to maintain.

Description

technical field [0001] The invention belongs to the field of civil engineering materials, and in particular relates to an internal curing sand for special concrete, a preparation method and application thereof. Background technique [0002] With the development of the construction industry, there are more and more high-rise buildings, large bridges and large prefabricated components in my country. In order to meet the requirements of construction, high-strength and ultra-high performance concrete, expansion and self-stressing concrete, high-strength self-compacting fair-faced concrete and other special concrete applications And more and more. [0003] The water-binder ratio of high-strength and ultra-high-strength concrete is small, and the cementitious material cannot be fully hydrated. The self-shrinkage of concrete increases with the decrease of the water-binder ratio, and even reaches more than 50% of the total shrinkage, which is easy to cause concrete shrinkage cracks a...

AI Technical Summary

Problems solved by technology

This kind of internal curing sand has small particle size, high bulk density, high strength and high water absorption rate, and is evenly distributed in concrete. It has good internal curing, reduces self-shrinkage and drying shrinkage, and increases the expansion of expansive concrete. High efficiency, improve the function of crack resistance, and solve the problems that cannot be solved by ordinary maintenance methods