Development of nanomodified-cementitious composite using phase change material for energy saving applications

In this study, a nanoengineered thermal-energy storing cementitious composite incorporated with a micro -encapsulated phase change material (m-PCM) and the combination of multi-walled carbon nanotubes (MWCNTs) and silica fume (SF), were developed for energy-saving purposes. m-PCM with a phase-change temperature of 5.5 degrees C and an enthalpy of 84 J/g was added to create latent heat storage in cement mortar. MWCNTs were added to improve the mechanical and thermal performance of the cementitious composite. m-PCM was incorporated in the cement mortar in proportions of 5%, 10%, and 15% by binder weight. However, the dosage of MWCNTs and SF kept constant at 0.05% and 10% by binder weight, respectively. A uniaxial compression test was performed to analyze the effect of m-PCM on the mechanical properties of the mortar. The compression test results showed a significant decrease in mechanical strength owing to the addition of m-PCMs. However, the addition of SF/ MWCNTs significantly enhanced the compressive strength of m-PCM mortars. A thermal-cycling test, assisted by an electrically-controlled-heated wire system, was performed to study the thermal response of nanoengineered m-PCM mortars with respect to varying ambient temperatures. The results revealed that the energy requirement for thermal regulation in m-PCM mortars with MWCNTs was reduced by approximately 60% as compared to the control specimen.