Numerical simulation of the effective thermal conductivity of cement-based composites: Microscopic insights into diatomite/silica aerogel

Silica aerogel used in cement composites to prepare novel thermal superinsulation material has been gradually applied in buildings and can effectively reduce building energy consumption. In this paper, the geometric voxel construction method is used to heterogeneity model the thermal conductivity of a cement-based diatomite/silica aerogel composite (DSAC), and thermal conductivity simulations are carried out using a heat conduction model framework analogous to an electrical resistance model framework. The simulation results show that the simulated thermal conductivities of cementitious DSAC materials with different DSAC composite contents agree well with the corresponding experimental values. The saturated thermal conductivity of the cementitious DSAC material is 2.5 times the dry thermal conductivity at 28 d. This shows that the thermal conductivity model proposed in this paper can effectively predict the effective thermal conductivity of cementitious DSAC materials and can provide strong support for the material design and performance prediction of cementitious DSAC materials.