Modeling thermal conductivity of aerogel-incorporated concrete: A multi-scale approach

The application of aerogel-incorporated concrete (AIC) in cement-based thermal insulation materials has attracted increasing attention due to its exceptional thermal insulation capabilities and environmentally friendly nature. To investigate its influence on the heat transfer properties of cementitious materials, we have developed a theoretical computational model of thermal conductivity with promotional potential. Considering the inhomogeneity of AIC and the underlying assumptions of the physical model, a theoretical method was devised to compute the multiphase equivalent thermal conductivity of AIC at the multi-scale. This was achieved by modifying existing thermal conductivity models for composite materials, including the shrinking-core, effective medium theory, and Hamilton-Crosser model. The proposed model takes into account various factors that impact the thermal conductivity of composite materials, such as the water-cement ratio, composition, age, and saturation level. Additionally, the theoretical upper and lower limits of thermal conductivity, as well as its sensitivity to influencing factors, were derived. Validated by test values, the theoretical computations based on microscopic components proved to be accurate and can be generalized. © 2024 Elsevier Ltd