Phase change material (PCM) for thermal energy storage (TES) is the material that can absorb energy during heating process as phase change takes place and release energy to environment during cooling process. Nowadays, energy consumption trends in construction building show a significant increase. It is important for reducing energy consumption in building by decreasing the energy demand and providing thermal human comfort inside the building. The objectives of this research are to determine the optimum percentage of PCM in concrete affected by time to achieve high thermal storage performance and evaluate the mechanical properties in different percentage of PCM concrete. Various percentage of 0%, 5%, 10% 15% and 20% of PCM concrete added with Ground Granular Blast Slag (GGBS) as filler were prepared and tested after 7 and 28 days of curing process. The result shows the thermal storage energy effective when integration with PCM in concrete. Besides, the compressive strength, water absorption and density measurement decrease with increasing amount of PCM. In conclusion, 5% of PCM with 30% GGBS added in concrete resulted in better thermal energy storage and compressive strength compared to other percentages of PCM concrete samples.
