THE CONCEPT OF USING RECYCLED CONCRETE AGGREGATES IN LOW-CARBON CONCRETE TECHNOLOGY

Abstract

The concept of using recycled concrete aggregates (RCA) contributes to the further development of one of the most promising sustainable construction technologies, which is consistent with the principles of the circular economy and decarbonization of the industry. The use of Portland cement with limestone CEM II/A-LL 42.5 R, combined active pozzolanic additive "fly ash - microsilica" ensures uniform passage of the pozzolanic reaction of components at different structural levels in the formation of a cementing matrix, which largely determines the characteristics of the modified concrete. The combination of components with polycarboxylate ethers provides modification of the mesostructure of the cementing matrix of concretes based on RCA and creates the possibility of achieving high mobility of mixtures and increasing the strength of recycled aggregate concretes. Multi-component cementitious materials fill the pore space of the cement paste and contribute to the compaction of the interface transition zone due to the reaction with calcium hydroxide to form C-S-H gels, which leads to improved recycled aggregate concrete characteristics. The integration of RCA into the production of building materials is an important step towards reducing construction waste, conserving natural resources and creating competitive solutions for the green transformation of the construction sector.