Jet dry material with low rebound rate and preparation method thereof

Abstract

The invention discloses a low-rebound-rate jet dry material and a method for reducing the rebound rate. The method comprises the following steps: controlling the fineness modulus of aggregate to be 4.0 + / -0.2 and the maximum particle size to be 7mm; ordinary cement is modified by special cement, so that the early strength and the sagging resistance are improved; additives such as cellulose ether and starch ether are used for tackifying, so that the sagging resistance is improved. The preparation process comprises the steps of raw material processing, metering, mixing and bulk packaging. The application process comprises the following steps: carrying out bulk transportation and entering of the spraying dry material, pre-adding water for mixing, and carrying out secondary water adding spraying construction. The invention provides a fineness modulus control method and a product performance detection method in a dry material production process. The rebound rate is effectively reduced through three comprehensive factors of controlling the gradation of the aggregate, improving the viscosity and the sagging resistance by using the additive and improving the early strength and the sagging resistance by using the special cement. The shotcrete engineering has the advantages of small comprehensive rebound rate, stable quality, convenience in construction, no need of building a stirring station on site, capability of being used while stirring, small occupied area, investment saving, low dust raising, resource saving, cleanness and civilization.

Description

technical field [0001] The invention relates to building materials, in particular to a spray dry material with low rebound rate and a preparation method thereof. Background technique [0002] Due to its rapid setting and early strength properties, shotcrete has been widely used in the initial lining support of subway tunnels, various structural reinforcements, building foundation pit slope support and other projects. [0003] At present, most projects prepare concrete on the construction site and then carry out "dry spraying", which has obvious adverse consequences: (1) On-site preparation of concrete requires more space for storing powder materials such as cement and fly ash, sand, stone, etc. Aggregate, quick-setting agent, water-reducing agent and other admixtures; both occupy land and may pollute the environment, especially in the downtown area, the contradiction is particularly prominent; (2) It is difficult to strictly control the quality and mix ratio of raw materials...

AI Technical Summary

Problems solved by technology

For pumping, fluid concrete should be prepared; however, fluid concrete is easy to fall on the sprayed surface, so a large amount of quick-setting agent must be mixed in; but the quick-setting agent cannot be added in advance, otherwise it is easy to block the pump and pipe; The quick-setting agent added at the mouth, no matter it is powder or liquid, is difficult to mix during the spraying process, which makes the strength of shotcrete fluctuate greatly, and the rebound rate is as high as 25%-40%.

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