A study on the effect of mixing methods and corresponding particle sizes on aerogel integrated lightweight mineralized foam

Lightweight mineralized foams (LMFs) incorporating aerogels can achieve desirable thermal insulation and show great potential as high-efficiency building insulation materials. However, the intrinsic brittleness of aerogels often causes particle fragmentation during mixing, while their defoaming effect disrupts the foam structure, making it difficult to evaluate the influence of aerogel particle size and distribution on material properties. In this study, different mixing procedures were designed to minimize aerogel–foam contact, reducing foam disruption while controlling the degree of aerogel crushing. Specimens containing aerogels of various particle sizes and contents were prepared, and their rheological properties, density, pore structure, compressive strength, and thermal conductivity were systematically characterized. The results showed that at low aerogel contents, variations in particle size had negligible effects on overall performance. However, in the small-particle group, a sharp transition occurred when the aerogel content exceeded 7.5 wt.%, with thermal conductivity decreasing to 0.033 W/(m ⋅ K) at 10 wt.%, representing a 31.25 % reduction compared to the 7.5 wt.% group. In contrast, large-particle specimens exhibited stable properties across all tested contents. These findings suggest that the observed differences are governed not merely by the relative particle sizes of the aerogels but more critically by the size relationship between the aerogel particles and the thickness of the cement matrix walls, as well as their spatial distribution within the structure. This study highlights the importance of tailoring aerogel size and dosage to the pore characteristics and density of LMFs, offering practical insights for optimizing multifunctional cement-based composites. • At high dosages, small aerogels tend to bridge between pores and block pore walls. • Oversizes aerogels induce dense cement layers, reducing insulation effectiveness. • Relation between aerogel and pore size/wall thickness matters more than particle size alone. • Aerogel spatial distribution strongly affects compressive and thermal properties. • The size of aerogel particles should be selected based on the material’s pore characteristics.