Theoretical calculation model for the thermal conductivity of scrap tire rubber–sand mixtures based on soil components

Scrap tire rubber is light mass and has heat-insulation properties. It can be mixed with building materials to form a new type of sustainable composite. Thermal conductivity is an important parameter affecting the thermal properties of building materials. Herein, the thermal conductivity of scrap rubber–sand mixtures was measured using a thermal probe; the effects of rubber content, moisture content, and dry density on the thermal conductivity of the mixture were studied, and a theoretical calculation model for the thermal conductivity of scrap rubber–sand mixtures was established. The results show that the thermal conductivity of scrap rubber–sand mixtures decreases with increases in the rubber content and reductions in the dry density. The thermal conductivity of the mixture increases with increases in moisture content. The established theoretical calculation model can accurately calculate the thermal conductivity of scrap rubber–sand mixtures, with R2 = 0.88, MAE = 0.044 (Wm−1 K−1), and RMSE = 0.071 (Wm−1 K−1). The prediction accuracy of the theoretical model is obviously superior to that of the traditional empirical model. It provides an accurate method for predicting the thermal conductivity of scrap rubber–sand mixtures.