Shotcrete admixture

Abstract

The invention discloses a shotcrete admixture. The shotcrete admixture is prepared from, by weight, 10-15 parts of a water-retaining agent, 15-20 parts of polyvinyl alcohol, 11-15 parts of a water reducing agent, 1-2 parts of polypropylene fibers, 58-62 parts of a cement accelerator, 3-20 parts of active montmorillonite, 10-25 parts of an accelerating agent, 1-12 parts of an acrylic copolymer, 1-2parts of sodium nitrite, 50-80 parts of expanded ultrafine silicon powder and 1-50 parts of calcium hydroxide. Shotcreting on normal seepage rock surfaces can be realized normally to greatly reduce rock surface seepage, the water reducing effect reaches 30% or above, 28-day strength can be improved to 50MPa, preparation of C40 anticorrosion shotcrete can be realized, and the problem of shotcreting in rock burst and water-abundant areas can be completely solved.

Description

technical field [0001] The invention relates to the technical field of admixtures, in particular to a shotcrete admixture. 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 i...

AI Technical Summary

Problems solved by technology

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.