Mechanical and microstructure development of portland cement modified with micro-encapsulated phase change materials

This paper investigates the mechanical and microstructure development of cement based materials containing different size of micro-encapsulated phase change materials (nano-MPCM and micro-MPCM). Thermogravimetric analysis (TGA) was used to analyze the effect of MPCM on the hydration products of hardened pastes. Scanning electron microscope (SEM) was performed to investigate the physicochemical stability of MPCM and microstructure of specimens. Mercury intrusion porosimetry (MIP) was employed to measure the pore structure at different curing age. According to the test results, both nano-MPCM and micro-MPCM can improve the compressive strength of thermal storage cement-based materials. While the compressive strength of specimens containing micro-MPCM was lower than specimens containing nano-MPCM. The production of C-S-H gel, calcium hydroxide and other products were increased as the MPCM incorporated. Both nano-MPCM and microMPCM had good physical stability in mixing process and good chemical stability in service process. With the increase of capsule dosage, the mean pore size and pore volume of the specimens decreased first and then increased.