Cement-ash concrete with the addition of lime kiln dust

The article is devoted to the study of the effect of lime kiln dust (LKD) on the properties of concrete mixtures and concrete using Portland cement and fly ash. A possible mechanism for the formation of the structure of cement-ash paste with the addition of LKD is analyzed in detail. The positive effect of LKD on hydration (an increase in the content of hydration water by 40.50%) and structure formation due to an increase in the alkalinity of the cement-ash paste is shown. Using the method of the experiment mathematical planning, experimental-statistical polynomial models of the concrete component (Portland cement, fly ash, dust, superplasticizer, and aggregates) content influence on the workability of the concrete mixture and the strength of concrete at different ages were obtained. The introduction of lime-carbonate components into concrete mixtures increases the strength of concrete by 27%-54%. At the same time, with the consumption of cement up to 200 kg/m(3), ash 100.150 kg/m(3), and LKD 50.100 kg/m(3), it seems possible to obtain concrete with a compressive strength of 20.30 MPa. The obtained models were analyzed, which made it possible to establish the positive effect of LKD additive on the compressive strength of concrete at the age of 7-180 days.