A special admixture for self-compacting and non-shrinkage steel tube concrete

Abstract

The invention discloses a special admixture for a self-compacting and non-shrinkable concrete filled steel tube. The admixture comprises the following components by weight: 30-50% of light roasted calcium oxide clinker, 10-30% of light roasted magnesium oxide clinker, 10-30% of plaster, 10-30% of flyash, 1-3% of a polycarboxylic acid high-performance water reducing agent, 0.1-1.0% of a thixotropic agent, 0.2-2.0% of a plastic foaming agent, 0.2-1.0% of a retarder and 0.5-2.0% of a defoamer. The special admixture has the beneficial effects that the mobility of newly blended concrete is improved, and compact filling of a mixture in the steel tube is guaranteed; the thixotropy of the newly blended concrete is enhanced, after a corresponding part is filled with the mixture, gel strength rapidly recovers and is improved, the movement resistance of entrapped bubbles is greatly improved, therefore, the entrapped bubbles cannot float or gather, and the top separation of the steel tube is remarkably improved; and the plastic foaming agent and a calcium and magnesium composite swelling agent completely compensates shrinking of the concrete filled steel tube in a whole process at different stages, therefore, the concrete is compactly attached to the wall of the steel tube, and cooperate stress is implemented.

Description

technical field [0001] The invention relates to a special admixture for self-compacting and non-shrinkage steel pipe concrete, which can significantly improve the workability of concrete, enhance thixotropy, compensate for shrinkage deformation, ensure its dense filling in the steel pipe structure, and make the concrete and the steel pipe wall cooperate Force. Background technique [0002] Concrete and steel are the two most important building materials that constitute modern building structures. The continuous improvement of the performance of these two materials and the research on the way of combining them have promoted the continuous innovation of building structures from components to systems. [0003] Concrete Filled Steel Tube is a typical structure in steel reinforced concrete (Steel Reinforced Concrete Structure) composed of steel and concrete. The synergistic effect of the two materials can give full play to the high compressive strength and bending resistance of t...

AI Technical Summary

Problems solved by technology

These methods are feasible, but not comprehensive enough: for example, adding defoamers can reduce the air content of concrete to less than 2.0%. For a period of time, there is still a phenomenon of small bubble aggregation, forming a large number of bubbles with a diameter of 0.5mm-5mm that continue to float up and gather at the top of the vault to cause voiding; the gas generation speed is too fast when the aluminum powder is mixed, and the hydrogen produced will bring steel The risk of structural hydrogen embrittlement damage; calcium expansion agent expands earlier, generally more than 90% of the entire expansion can be completed within 7 days, and the effect of compensating for the late shrinkage and deformation of steel pipe concrete is not good

Images