Using concrete as a thermal energy storage (TES) material is a promising option for large-scale solar-thermal resource development and utilization. Specific heat is one of the most important characteristics for TES performance. In this paper, the half-open dynamic method based on the mixing principle is proposed and applied to measure concrete-specific heat at temperatures up to 600 °C. Measurement of the specific heat of corundum ceramic (99% Al₂O₃) is first performed, and the test results illustrate the accuracy and efficiency of the proposed test method. Furthermore, concrete-specific heat tests are carried out at high temperatures. It found that the specific heat increases as the temperature rises, especially, linearly in the range of 300–600 °C, in which the concrete TES module is expected to be in operation. Finally, the effect of concrete-specific heat changes with temperature on its TES capacity is investigated, demonstrating that specific heat is of great significance for concrete TES design for concentrating solar power.

This study investigated the effects of different casting procedures on compressive strength, water permeability, and interfacial transition zone (ITZ) porosity of rock-filled concrete (RFC). Mixes of concrete with the same proportions were cast using the self-compacting method (the casting procedure of RFC) and the vibration method (the casting procedure of normal concrete). A control group of concrete was prepared to reveal the effects of aggregate size. Compressive tests and water permeability tests were performed in accordance with the current codes. Scanning electron microscopy was used to calculate the porosity of the ITZ by processing the second electron and backscattered electron images of the ITZ. The findings indicate that the self-compacting method can improve compressive strength and particularly impermeability grade. Switching the vibration method to the self-compacting method also significantly reduces ITZ porosity, especially the ITZ porosity at the lateral surface of the aggregate.