Technological Aspects of Usage of Calcareous Fly Ash as a Main Constituent of Cements

Abstract

The use of mineral additives allows you to modify the properties of concrete and result in substantial economic benefits. The research the influence cement type with calcareous fly ash (W) content in cement, method of cement production, activation by grinding calcium fly ash and batch of fly ash on the rheology, plastic shrinkage, air content, the setting time and heat of hydration of mortar are presented in this paper. The results show that cements produced by intergrinding of the constituents or blending with fly ash pre-processed by milling, are characterized by acceptable technological properties, not differing significantly from other currently used cements. It is not recommended to use cements obtained by blending with raw calcareous fly ash W. Calcareous fly ash used for the production of cement should be selected because of its properties. According to conducted tests, this criterion can be the volume density of the ash, which should be at least 900 kg/m3. The negative effect of calcareous fly ash used as an additive for cement on workability is considerably smaller than when it is used as an additive type II.