Method for preparing construction waste micro-powder composite admixture

Abstract

The invention discloses a method for preparing a construction waste micro-powder composite admixture. The method comprises the steps of: evenly mixing construction waste with lime and desulfurized gypsum, and grinding at room temperature to obtain a micro-powder mixture with specific surface area larger than 400m<2> / kg, wherein the mixing weight of the construction waste accounts for 90%-98% total weight of the micro-powder mixture, the mixing weight of the lime accounts for 1%-5% and the mixing weight of the desulfurized gypsum accounts for 1%-5%; mixing the ground micro-powder mixture with an additive of which the weight accounts for 1%-5% total weight of the micro-powder mixture to obtain a mixed material; and mixing the mixed material with slag in a weight ratio of 1:1 and then carrying out ball milling until the specific surface area of the material is larger than 450m<2> / kg, thereby obtaining the construction waste micro-powder composite admixture. The method has the advantages that the alkalinity of concrete can be supplemented, the mixing quantity of a construction waste micro-powder auxiliary gelation material in the concrete is increased and the carbonization resisting capacity of the concrete can be improved.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to a preparation method of construction waste micropowder composite admixture. Background technique [0002] With the advent of a new round of urban construction peaks, continuous urban expansion, and continuous renovation of old cities, a large amount of construction waste is generated. The traditional processing methods of these construction wastes are mostly transported to the suburbs to fill the ditch, piled up randomly or screened out waste concrete to produce recycled aggregate. In addition to the huge processing costs of these traditional treatment methods, 80% of the brick and tile waste in construction waste still cannot be effectively disposed of, and these brick and tile waste still need to occupy a large amount of vacant land, which not only wastes cultivated land, but also seriously pollutes the environment. The natural environment on which people live, cons...

AI Technical Summary

Problems solved by technology

Excessively high slag powder content will reduce the alkalinity of the pore solution inside the concrete, and the decrease of the pore solution alkalinity will affect the hydration activity of the slag powder on the one hand, that is, affect the early strength of the concrete; on the other hand, it will lead to concrete Decreased resistance to carbonation and increased cost of concrete materials