Composite admixture for high-speed railway rail slab concrete

Abstract

The invention belongs to the technical field of civil engineering materials, and particularly relates to a composite admixture for high-speed railway rail slab concrete, wherein the composite admixture is prepared by mixing the following components: 20-55% of a sub-nanometer mineral material, 20-45% of superfine slag powder, 25-45% of glass micro-bead, 0.1-0.5% of a water reducer, 0.1-0.5% of a defoamer, 1.0-2.0% of an excitant, 1.0-3.0% of nanometer silicon dioxide, and 0.2-1.0% of an enhancer. According to the present invention, the composite admixture does not contain chlorine salts, does not rust steel bars, can rapidly increase the early strength of concrete and rapidly reduce the curing temperature, can further provide effects of concrete hydration heat release rate reducing, concrete cracking reducing and concrete volume deformation reducing, and can effectively solve the problems of slow early demolding strength increase, high curing cost and easy rail slab cracking and warpagedeformation of the existing rail slab concrete production process.

Description

technical field [0001] The invention belongs to the technical field of civil engineering materials, and in particular relates to a composite admixture for high-speed railway track slab concrete. Background technique [0002] High-speed railway slab ballastless track structure has become the main structural form of high-speed railway in my country due to its high ride comfort and low maintenance. After the structural form, it has now developed to the CRTSIII type slab ballastless track structure with independent intellectual property rights. One of the key components of the slab ballastless track structure is the track slab. The track slab is produced by factory prefabrication. In order to speed up the formwork turnover, improve production efficiency and reduce production costs, the track slab production line develops the demoulding strength of the track slab concrete. The requirements are relatively high, and it is required to reach a demoulding strength of 48MPa within 16 h...

AI Technical Summary

Problems solved by technology

At the same time, the temperature of the concrete core of the track slab should not exceed 55°C, because an excessively high core temperature will increase the risk of cracking of the track slab concrete

In the actual production of track slabs, it is found that since the production process of track slabs is a foreign technology, and foreign countries mostly use ultra-fine cement to produce track slabs, it is easy to achieve rapid growth in the early demoulding strength of track slab concrete. Less, high price, not suitable for large-scale use, only ordinary Portland cement or Portland cement can be used for production, so it is difficult to ensure the 16h demoulding strength requirement of track slab concrete in actual production, and the production speed is sometimes delayed Case

At the same time, in the production of track slabs, it was also found that due to the high amount of cementitious materials used in track slab concrete, low water-binder ratio, and the use of steam curing, the volume deformation of track slab concrete is also large, and the problem of warping deformation of track slabs is prone to occur

Images