Synergistic effects of surfactant-based foaming agents and HPMC on silt-based foamed concrete

Silt-based foamed concrete (SFC) is a sustainable alternative for lightweight construction materials. However, its widespread use is often limited by poor foam stability and less-than-ideal mechanical properties. This study systematically investigates the synergistic effects of three representative foaming agents—sodium lauryl sulfate (K12), sodium lauroyl sarcosinate (LS-97), and animal protein (AP)—combined with hydroxypropyl methylcellulose (HPMC) as a foam stabilizer on the performance of SFC. A series of pre-foaming experiments were conducted to examine how foaming agent concentration and HPMC content affect foam characteristics, slurry rheology, compressive strength, and dry density. The results showed that the K12–HPMC system achieved the highest foaming ratio of 126.2. The AP–HPMC system had the longest foam half-life, reaching 648 min. HPMC effectively improved foam stability and mechanical performance. For example, the K12–HPMC system exhibited a 57% increase in compressive strength. Dry density increased with HPMC dosage in all systems. We developed regression models ( R 2 > 0.95) that accurately predict compressive strength based on component concentrations, providing reliable tools for mixture design. These findings advance the fundamental understanding of foam stabilization and offer practical strategies for developing high-performance SFC, facilitating its large-scale implementation in resource-efficient construction.