Preparation method of low-grade activated coal ash composite material

Abstract

The invention relates to a preparation method of a low-grade activated coal ash composite material applied to cement and concrete. The low-grade activated coal ash composite material is prepared by taking the low-grade coal ash as a main raw material and slag, red mud, and other industrial waste residues, limestone powder and semi-hydrated gypsum as auxiliary materials through the combined action of physical milling and activating and chemical excitation. In the process of mixing concrete materials, 30% by weight of the activated coal ash composite material is used to replace PO52.5, PO42.5 or PO32.5 silicate cement; under the circumstance that other mixing materials remain the same, a great amount of cost can be saved for mixing the concrete per cube meter; the strength of the mixed concrete at all ages is equal to or higher than that of contrast concrete; the newly mixed concrete has the characteristics of high workability, low slump loss, low heat of hydration, good transitive performance of long-term strength, high resistance to sulfate attack, high chemical resistance, high durability, and the like; and the added coal ash composite material has no adverse effect on the performance of the concrete.

Description

technical field [0001] The invention relates to a method for preparing a composite material used in cement and concrete, in particular to a method for preparing an activated low-grade fly ash composite material. Background technique [0002] Fly ash is a powdery substance discharged during the production process of coal-fired thermal power plants. my country's annual output of fly ash is nearly 400 million tons, of which only higher-quality grade I and grade II fly ash, which account for less than 10% of the total output, are used as cement mixtures and mineral admixtures for concrete, and the remaining nearly 90 The low-grade fly ash of Grade Ⅲ and below has not been applied in the production and mixing of cement and concrete because of its low activity and large fineness, which cannot meet the performance requirements of concrete, and most of them are discharged directly. Or for roadbed construction, fly ash brick production, etc. The discharge of fly ash will not only cos...

AI Technical Summary

Problems solved by technology

my country's annual output of fly ash is nearly 400 million tons, of which only higher-quality grade I and grade II fly ash, which account for less than 10% of the total output, are used as cement mixtures and mineral admixtures for concrete, and the remaining nearly 90 The low-grade fly ash of Grade Ⅲ and below has not been applied in the production and mixing of cement and concrete because of its low activity and large fineness, which cannot meet the performance requirements of concrete, and most of them are discharged directly. Or used for roadbed construction, fly ash brick production, etc.

The discharge of fly ash will not only cost a lot of money to build a stacking site, but also occupy a large amount of land, and it is easy to generate dust in windy weather, which seriously pollutes the environment