关键词: 泡沫混凝土, 纳米TiO₂, 泡沫稳定性, 抗压强度, 微观形貌, 孔结构

Abstract: To address the issue of poor stability of ordinary foaming agents, nano-TiO₂ was used to modify ordinary foaming agents in this paper. The effects of nano-TiO₂ content on foaming multiple, sedimentation distance and bleeding rate of foaming agent were investigated, while also effect of modified foam agent on the mechanical properties and microstructure of foam concrete was analyzed. The results indicate that nano-TiO₂ can effectively improve the performance of foaming agent. When with the optimum content of nano-TiO₂ is 0.15% (mass fraction, the same below), the foam multiple increases by 11.93%, the 1 h sedimentation distance and 1 h bleeding rate decrease by 54.29% and 12.21%, respectively, and the average thickness of the foam liquid film is 37.86 μm. The 3 d compressive strength of foam concrete prepared by adding 0.15% nano-TiO₂ is 1.637 MPa, which is 41.98% higher than that of the control group. Microscopic analysis reveals that nano-TiO₂ can obviously improve the porosity of foam concrete, and promote the formation of more calcium silicate hydrate (C-S-H) gels during the curing process of foam concrete slurry, so that the mechanical properties of foam concrete are significantly improved.

Key words: foam concrete, nano-TiO₂, foam stability, compressive strength, microstructure, pore structure