Compound coal ash for concrete

Abstract

The invention relates to compound coal ash for concrete. The compound coal ash for concrete is prepared according to the following steps: mixing basalt macadam with a grain size less than 50 millimeters and wet coal ash with a moisture content of 15 to 25 percent with hearth slag; drying the mixture; grinding the mixture into powder; and controlling the fineness being 45 microns and the residue on a square hole screen being less than 15 percent and the moisture content of the ground powder being less than 0.5 percent. The production process is simple; the cost is low; the industrial wastes, such as wet coal ash, hearth slag, and the like, are taken as raw materials; a part of cement in the concrete can be replaced by the obtained compound coal ash; the mechanical property and the durability of the concrete can be efficiently increased; the resource and energy source are saved; the industrialized production is boosted; and the environmental protection and the energy saving and emissionreduction are boosted.

Description

technical field [0001] The invention belongs to the field of construction, and relates to a construction material, in particular to composite fly ash for concrete. Background technique [0002] Concrete refers to using cementitious materials (such as cement), sand and stone as aggregates, mixed with water (with or without admixtures and admixtures) in a certain proportion, and obtained through stirring, molding and curing. One of the main civil engineering materials. In order to improve the workability of the concrete mixture or the performance of the hardened concrete, a finely ground mineral material-admixture is added to the concrete during mixing to replace part of the cement and reduce the amount of cement. The nature and quantity of the admixture , affecting the strength, deformation, heat of hydration, impermeability and color of concrete. [0003] At present, concrete admixtures are mainly primary and secondary fly ash, granulated blast furnace slag powder, and ste...

AI Technical Summary

Problems solved by technology

At present, the use of wet-discharged fly ash as a concrete admixture has the following shortcomings: First, wet-discharged fly ash is used as a slurry, but the water content is difficult to control, and because the wet-discharged ash site is not next to the concrete mixing station, The slurry is difficult to transport and the quality is unstable, and it is difficult to guarantee the quality when it is made into concrete; the second is to dry the wet fly ash before grinding, the production process is dusty, the air pollution is serious, the energy consumption is too high, and the cost is high

The above two methods of using wet-discharged fly ash in concrete have the problems that the product quality is not easy to control, especially the ignition loss, sulfur trioxide content, stability and free calcium oxide content are easy to exceed the standard, etc.

Images