Optimizing mix proportion and properties of lightweight concrete incorporated phase change material paraffin/recycled concrete block composite

Abstract In this study, the phase change material paraffin/recycled concrete block composite (PCMPC) was prepared and used as fine aggregate in manufacturing of lightweight concrete (LWC). The mix proportions of LWC were designed using Taguchi method. L 9 orthogonal array with four factors viz., water/cement (W/C) ratio, water content, PCMPC content and sand/cement (S/C) ratio were selected for the optimization of LWC. The most important factors influencing the properties of LWC were investigated using analysis of variance (ANOVA). Based on the results, the phase transition and latent heat of PCMPC showed good thermally reliable and chemically stability after thermal cycling test. The density and compressive strength of samples containing the PCMPC were in the range of 1711–1812 kg/m 3 and 33–53 MPa, respectively. The density and compressive strength of samples can meet the requirement of lightweight concrete for structure application according to ASTM C330/C330M-14. The results also showed that PCMPC was the most significant factor for heat storage coefficient. The thermal energy absorption and release characteristics of LWC containing PCMPC were significantly better than those of the control sample. The fine PCMPC aggregate is thus another novel building material for use in thermal conditioning of building which can reduce and save electricity consumption.