Cement-based engineering composite railway sidewalk cover board preparation process and product

Abstract

The invention discloses a cement-based engineering composite railway sidewalk cover board preparation process and a product, and the preparation process is used for preparing light-weight high-strength railway sidewalk cover boards. The raw materials comprise the following components in parts by weight: 100 parts of cement, 10-60 parts of coal ash, 5-20 parts of silica fume, 1.0-2.0 parts of water reducer, 1.0-2.0 parts of polyvinyl alcohol fiber, 0.1-0.5 parts of polyvinyl alcohol fiber and 20-50 parts of silica sand. The product is formed under the frequency of 3000 Hz and the amplitude of 1mm, steaming under 40 DEG C or submerging 7d for maitenance is carried out, and then ordinary maintenance is carried out to obtain the high-performance target product. According to the process, the obtained cover board has excellent property, the shock resistance, crack resistance and corrosion resistance are greatly improved, the 28d bending strength can reach more than or equal to 18 MPa, the 28d pressure resistance is more than or equal to 75 MPa, and 56d electric flux is less than or equal to 100 C. The the shock resistance, crack resistance and corrosion resistance of the cover board are greatly improved, and the cover board is light in weight and high in strength, convenient in installation and free of electric conduction or hand prick.

Description

technical field [0001] The invention relates to building components, in particular to the technical field of preparation of cement-based engineering composite material railway sidewalk cover plates. Background technique [0002] In recent years, my country's high-speed railways have developed rapidly. On the basis of a large number of high-speed railway lines that have been built, there are still a large number of branch railways, intercity railways, and subway lines that are being planned and constructed, which will set off a new upsurge in railway construction. When the bridge of high-speed railway or passenger dedicated line adopts integral sidewalk baffle, due to the large vibration load, wind force and train wind load, the size of the baffle is large and the weight is heavy; For the corresponding load, the section height needs to be increased, and the self-weight will also increase. There are many bridge deck facilities on the passenger dedicated line, and the combinat...

AI Technical Summary

Problems solved by technology

In the specification "Reactive Powder Concrete (RPC) Material Railway Sidewalk Baffles and Covers", it is stipulated that the flexural strength of RPC is ≥18MPa. In order to meet this requirement, the existing RPC is mixed with 80-120kg / m 3 Such a large number of steel fibers easily form overlapping joints, and finally form a conductive network structure, especially when the steel fibers are not dispersed and the mix ratio is not well controlled. This phenomenon has already occurred in the field, bringing great security risk

[0005] In addition, the rust problem of steel fiber

According to the existing specifications, in order to prevent the steel fibers in RPC from rusting, the steel fibers used in RPC must be copper-plated steel fibers. However, due to the ultra-low water-cement ratio of RPC, it is very difficult to stir and form it, and it takes a long time and high Intensive forced stirring for more than ten minutes will easily cause the copper plating layer on the surface of the steel fiber to wear, and eventually the steel fiber will be directly exposed to the cement matrix, and because the sidewalk baffle and cover plate are thin, the thickness is only 2.5-5.0cm, so Steel fibers are easily corroded, and the rust of steel fibers can often be seen with the naked eye on site

[0006] There is also the problem of steel fiber sticking hands

Because RPC is mixed with a large amount of steel fibers, the exposed slender steel fibers are easy to prick hands. Whether it is during RPC production or RPC installation, it is often seen that workers’ hands are punctured and bleed, which leads to a decrease in production and installation efficiency, and brings A very serious personal safety problem has arisen. Since the cover plate needs to be lifted during troubleshooting, this will also make it extremely inconvenient to troubleshoot railway cables in the future. A large number of complaints about such problems have been received on site

[0007] In addition, due to the high-temperature steam curing of RPC, the brittleness of cement hydrate is too large, and the brittleness is too strong, which is prone to brittle fracture; due to the steel fiber density of 7.9g / m 3 , leading to excessive density of RPC and heavy single cover plate, resulting in difficulty in installation, maintenance, and transportation; mixing a large amount of steel fibers, and adopting 80°C steam curing, resulting in high material and production costs, etc.