This article examines the environmental, economic, and technological aspects of using rice husk ash (RHA) in the construction industry. It is shown that the use of this waste from the rice processing industry helps reduce the carbon footprint and improve the quality of cement paste. The results of an experimental study of the effect of RHA on the physical and mechanical properties of cement paste are presented. Patterns of change in setting time, water requirement, strength, and hardening kinetics are established when replacing part of the Portland cement with RHA in quantities of 5, 10, 15, and 20% of the cement mass. It is shown that the optimal content of the additive is 15%, which improves the strength properties of cement paste at the age of 28 days by 10% compared to conventional cement.

Keywords: rice husk ash, Portland cement, cement paste, setting time, water requirement, strength, hardening kinetics, pozzolanic activity