Experimental investigations were carried out on the thermal and mechanical properties of sleeve grouting materials subjected to elevated temperatures up to 900°C. The thermal properties, including thermal conductivity, specific heat, and thermal expansion, as well as the temperature-dependent compressive strength were obtained from the experiments. Simple calculation methods were proposed to predict the thermal properties and strength of the material subjected to elevated temperatures. The experimental results showed that the thermal conductivity and the compressive strength of the materials decreased while the heat capacity and thermal strain increased with the increase of temperature. Degradation of the sleeve grouting materials under elevated temperatures was investigated through microanalytical tests.