Abstract
The possibility of improving the strength properties of concrete materials based on ash/slag waste from thermal power plants of Almaty (Kazakhstan) by adjusting their chemical composition is considered. An X-ray phase analysis, scanning electron microscopic (SEM) analysis, infrared analysis (IR), and elemental determination analysis (EDAX) of ash and slag wastes were carried out, and additives to correct their chemical composition were selected. The analysis of the conducted studies shows that the addition of polypropylene fiber leads to an increase in the compressive crack resistance compared to the composition of the mixture in which ash is present. The highest compressive strength in which cenospheres increase in strength characteristics is observed on samples modified with 7% cenospheres. It was found that the strength of the concrete with the addition of cenospheres increased by more than two times in comparison with a sample without additives.