INFLUENCE OF LIGHTWEIGHT AGGREGATES AND INDUSTRIAL WASTE ON THE PHYSICAL AND MECHANICAL PROPERTIES OF DRY BUILDING MIXTURES

Abstract

The article presents the results of a study on the influence of lightweight aggregates and industrial waste on the physical
and mechanical properties of dry building mixtures (DBMs). The research problem is determined by the need to introduce
environmentally safe and resource-efficient technologies in modern construction, which requires replacing part of the
traditional mineral components with secondary resources. Perlite, vermiculite, and expanded clay sand were used as
lightweight aggregates, while fly ash, granulated blast furnace slag, cement kiln dust, and stone-cutting waste were applied
as industrial by-products. The water-to-binder ratio, bulk density, and compressive strength at 28 days were determined.
Regression modeling was employed to establish quantitative relationships between mixture composition and properties. It
was found that the introduction of perlite or vermiculite in the amount of 10-15% reduces the density by 18-25%, providing
thermal insulation properties while maintaining compressive strength at the level of 10-13 MPa.
The addition of fly ash in the amount of 20-25% ensures an optimal water-to-binder ratio and improves crack resistance.
The combined use of fly ash with stone-cutting waste (5-10%) enhances structure formation and maintains strength at 12-
13 MPa. Special attention was given to recycled aggregates obtained from construction and demolition waste. The study
demonstrated that recycled concrete and reinforced concrete meet national standards and allow the production of C16/20
class concretes. Therefore, the combination of lightweight aggregates, industrial by-products, and recycled fractions
enables the production of universal DBMs with densities ranging from 1200 to 2300 kg/m³ for various applications – from
finishing and insulating to structural mixtures. The proposed approach contributes to reducing natural resource
consumption, lowering production costs, and addressing the problem of construction waste recycling.