Influence of additives and temperature regime on the setting kinetics and strength of foamed concrete

The article presents the results of the development of the physico-mechanical characteristics of fast-setting lightweight concrete. Based on the obtained data, it was concluded that the use of metal cassette molds in foam concrete technology is ineffective. Their turnover can be increased by heating the floor in the workshop and insulating the sides and surfaces of the molds. However, the high cost of energy carriers increases the material's production cost and reduces its competitiveness. At ambient temperatures below 16 °C, it is advisable to use insulated wooden molds, which help retain the heat released during cement hydration. The optimal mold dimensions (1.2 × 1.25 × 0.5 m and 1.2 × 1.25 × 0.6 m) were selected based on cutting technology capabilities. The formation of large monolithic masses is associated with the risk of cracks and even structural rupture due to uneven heat distribution. To maintain the initial mix temperature within 22 – 25 °C, the molding mixture should be prepared using water heated to 30 °C. In insulated wooden molds, the formed material retains a temperature of at least 18 – 20 °C before the onset of hydration. Then, due to the exothermic reaction of cement, the temperature remains stable until demolding. Improvements in natural-setting foam concrete technology have demonstrated the feasibility of introducing a chemically active siliceous component into the mixture. This component binds free Ca(OH)₂ released during alite hydration, contributing to long-term strength development. Research objective – The development of effective methods to accelerate the early-stage hardening of foamed concrete by studying the influence of electrolyte additives and surfactants on the setting and hardening processes of cement paste. The novelty of work lies in establishing patterns in the formation of physical and mechanical properties of foamed concrete with accelerated initial hardening, taking into account its porous structure, and the characteristics of the hardening process.