Concrete spraying additive

Abstract

The invention discloses a shotcrete admixture, comprising: 13 to 15 parts by weight of cold water quick dissolving powdery methylcellulose ether or cold water quick dissolving powdery hydroxyethyl cellulose ether, 13 to 15 parts by weight of cold water quick dissolving powdery polyvinyl alcohol, 8 to 11 parts by weight of naphthalene-series powdery water-reducing agent, 1 to 2 parts by weight of mesh polypropylene fiber and 58 to 62 parts by weight of cement accelerator. The shotcrete admixture is prepared by adding the constituents into the concrete together for increasing the cohesion of concrete and viscosity of early-stage slurry, the slurry initial setting time is short, and the resilience amount of concrete can be reduced by 30 to 50 percent.

Description

technical field [0001] The invention relates to an inorganic material, especially an admixture added to shotcrete. Background technique [0002] At the beginning of the 20th century, Germany developed and applied shotcrete mortar to support the roadway. In the early 1950s, the research of simple sprayer and accelerator was successful, which created conditions for the application of shotcrete technology. By the 1980s, shotcrete technology had developed from the single dry spraying in the past to various forms such as tidal spraying, wet spraying, cement-coated sand shotcrete, and steel fiber shotcrete. Practice has proved that compared with cast-in-place concrete, sprayed concrete is simple and easy to construct, saves the process of formwork, pouring and form removal, and integrates concrete transportation, pouring and tamping into one process, which saves manpower, shortens the construction period, and saves time. It can be constructed in thin-walled structures in high roo...

AI Technical Summary

Problems solved by technology

[0003] However, the high rebound rate and unstable spraying quality are problems that have plagued the development of shotcrete for a long time.

In actual construction operations, the rebound rate of shotcrete is generally above 30%, and some even exceed 40%, which causes material waste and affects project quality and construction progress.

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