Development and characterisation of myristic acid-paraffin wax, silica fume and zinc oxide cementitious composites for thermal control in buildings

This study focuses on the development of a cement-based phase change material (CBPCM) to improve thermal performance in construction applications. The CBPCM was synthesised by blending 90 wt% of myristic acid with 10 wt% of paraffin wax, absorbed into 10 wt% of silica fume to prevent leakage. Additionally, 5 wt% of zinc oxide was added to improve thermal conductivity. A leakage test conducted with 10 wt% of SF exhibited no signs of leakage during thermal cycling. Scanning electron microscopy (SEM) established the uniform dispersion of the nano-enhanced phase change material (NEPCM) within the cement. Fourier transform infrared spectroscopy (FTIR) analysis revealed no chemical structure changes after 100 thermal cycles. Thermogravimetric analysis (TGA) confirmed thermal stability in the temperature range of 74.8 to 236.64 °C with a mass loss of 6.3 wt%. The material demonstrated minimal variation in phase change temperatures and latent heats after 100 cycles. The latent heat of the CBPCM was 1.09 J/g during melting and 1.887 J/g during solidification. Incorporating NEPCM into the cement increased the thermal conductivity of the cement matrix to 0.559 W/m K. These findings underline the potential of the CBPCM for energy-efficient construction, offering enhanced thermal storage, stability, and conductivity. • Developed CBPCM with 10 wt% (90 wt% MA, 10 wt% PW, 10 wt% SF and 5 wt% ZnO). • 10 wt% of SF absorbed PCM without leakage. • After 100 thermal cycles, CBPCM exhibited stable latent heats of 145.86 J/g (melting) and 169.27 J/g (solidification). • 5 wt% of ZnO increased thermal conductivity from 0.1381 to 2.63 W/m K. • NEPCM improved cement thermal conductivity to 0.559 W/m K.