Management of Chemical Processes in the Production of Thermal Insulation Materials to Improve Water Resistance and Environmental Safety

Thermal insulation materials play a crucial role in improving the energy efficiency and durability of buildings; however, their long-term performance can be significantly affected by moisture exposure. This study investigates the relationship between the formulation parameters, water susceptibility, structural stability, environmental performance, and economic efficiency of lightweight thermal insulation composites. Ten experimental formulations were produced by systematically varying the cement content, water-to-cement ratio (W/C), gas-forming powder content, and polymer-modifying additives. Water resistance was evaluated through controlled immersion tests and measurements of mass variation and structural condition, supported by response-surface analysis. The experimentally determined water susceptibility ranged from 2.1% to 6.8%, demonstrating a systematic increase with increasing W/C ratio and gas-forming powder content. The most favorable result was obtained for composition no. 1, characterized by a W/C ratio of 0.55 and a powder content of 0.14 g, which exhibited the lowest water susceptibility of 2.1%. In our previous studies, the developed waste-based thermal insulation materials demonstrated a density of up to 550 kg/m3 and thermal conductivity below 0.12 W/(m·K). Building on these results, the present study focuses on their water absorption and water-resistance characteristics. Composition No. 1 also showed the lowest estimated material cost, approximately EUR 0.120/kg (EUR 66.04/m3), demonstrating that improved moisture resistance can be achieved without compromising economic efficiency. The results establish a quantitative composition–structure–property relationship and demonstrate that coordinated control of the W/C ratio, pore-forming component, and polymer modifiers is essential for balancing moisture resistance, thermal performance, material cost, and environmental sustainability. The proposed integrated assessment framework supports the development and selection of durable thermal insulation composites for sustainable construction, while further long-term durability, leaching, and life-cycle assessments are required to confirm their environmental performance under realistic service conditions.