Hungeret al. [16] reported both mechanical and thermal behaviors of self-compacting concrete with microencapsulated PCM.
They found that addition of microencapsulated PCM resulted in concrete compressive strength reduction; while thermal properties were obviously improved, for example, clear reduction on thermal conductivity and evident enhancement on thermal mass.
Similar experimental results were also revealed by Meshgin and Xi
[17,18]. Although these commercial microencapsulated PCMs showed good thermal impact on the developed thermal energy storage cement-based composites, they had some incompatibility problems with cement matrix.
Damaged microencapsulated PCMs with polymer shells broken were found in cement matrix due to collision and abrasion with aggregates and also high pH environment of cement hydration system [16].
Zhang et al. [10] incorporated n-octadecane/expanded graphite composite PCM into cement mortar. Thermal energy storage performance of mortar was significantly improved, as expected. However, mechanical property of mortar was dramatically decreased even at small addition amount of 2.5%. It suggested possibly poor bond between expanded
graphite and cement matrix.