Efficient use of solar energy by thermal energy storage composites and utilizing environmentally friendly cementitious materials are important trends for sustainable building composite materials. In this study, a paraffin/low density polyethylene (LDPE) composite shape-stabilized phase change material (SSPCM) was prepared and incorporated into a sulphoaluminate cement (SAC) mortar to prepare thermal energy storage mortar. The thermal and mechanical properties of SSPCM and a SAC-based thermal energy storage material (SCTESM) were investigated. The result of differential scanning calorimeter (DSC) analysis indicates that the latent heat of SCTESM is as high as 99.99 J/g. Thermogravimetric analysis demonstrates that the SCTESM does not show significant decomposition below 145 °C. The volume stability test shows the volume shrinkage percentage of the SCTESM is less than that of pure SAC mortar and far less than that of ordinary Portland cement mortar. The SCTESM has high early strength so that the compressive strength at 1-, 3-, and 7-day curing age is up to that at 28-day curing age of 67.5%, 78.3%, and 86.7%, respectively. Furthermore, a mathematical prediction model of the SCTESM compressive strength was proposed. The investigation of latent heat storage characteristics and the thermoregulating performance reveals that SCTESMs have the excellent capacity of heat storage and thermoregulating.

In this study, an ultra-light ordinary Portland cement-based thermal insulation material (ULCFTIM) with an apparent density of less than 300 kg/m³ was developed using physical foaming technology. The problem of ULCFTIM collapse during the preparation process was solved by adding sulphoaluminate cement (SAC). The influence of SAC mass fraction and water-cement ratio on the thermal conductivity and compressive strength of ULCFTIM was researched. The experimental results show that increasing the SAC is beneficial to the compressive strength of ULCFTIM at 3 days, but decrease the compressive strength of ULCFTIM at 28 days. The optimal mass fraction for SAC in a cementitious material is 10%. With the water-cement ratio increases, the compressive strength first increases and then decreases, and the thermal conductivity decreases first and then stabilizes. When w/c values ranging from 0.26-0.30, ULCFTIM has a good performance with compressive strength between 0.185 MPa and 0.201 MPa and thermal conductivity between 0.701W ⋅m^-1⋅K^-1 and 0.714 W ⋅m^-1⋅K^-1.