LIGHTWEIGHT CONCRETE COMPOSITIONS FOR MULTILAYER ENCLOSING STRUCTURES

Abstract

Lightweight concretes are widely used in construction, however, achieving an optimal balance between thermal insulation and strength characteristics remains an urgent scientific and technical task. The purpose of this study is to develop multilayer lightweight concrete with a variotropic structure based on expanded polystyrene fillers and adjustable porosity of cement stone using air-entrapping additives. Experimental studies of the effect of the composition of the mixture, the content of expanded polystyrene and the porization parameters on the density, compressive strength and thermal conductivity of the material were carried out. It was found that an increase in porosity of up to 4.5% due to the use of air-entrapping additives allows maintaining strength at the required level (up to 2.8 MPa for thermal insulation layers and up to 39.0 MPa for structural layers) while reducing the coefficient of thermal conductivity to 0.095 W/(m·°C), which is 15-30% lower compared with traditional lightweight concrete. The scientific novelty of the research lies in the development of a variotropic multilayer structure with a controlled distribution of density and porosity over the thickness of the material, providing a targeted combination of strength and thermal characteristics. The proposed approach makes it possible to reduce the average density of the material, increase the energy efficiency of enclosing structures and can be used in the design of energy-efficient buildings.