Thermal management performance and mechanical properties of a novel cementitious composite containing fly ash/lauric acid-myristic acid as form-stable phase change material

•Fly ash (FA)/lauric acid (LA)-myristic acid (MA) was developed and characterized as novel form-stable composite (FSC).•The FSC including 27 wt% LA-MA has a melting temperature and latent heat capacity of 31.1 °C and 45.3 J/g.•The FSC was were incorporated into the standard cement mortar to produce thermal energy storage cement mortar (TES-CM.•TES-CMs have sufficient mechanical properties to be used in plaster form in buildings.•TES-CM 20 sample showed remarkable temperature regulation performance. To enhance the thermal mass of buildings, form-stable fly ash/lauric acid-myristic acid eutectic mixture composites (FSC) were incorporated into the standard cement mortar to produce novel cement mortars with ability of heat charging/discharging properties. The chemical, crystalline and morphological properties of the produced FSC were examined by FTIR, XRD and SEM, respectively. Thermal properties were determined by DSC, TGA and thermal cycling test. FTIR results demonstrated that there was a good compatibility between FSC components and no chemical interaction was detected between them. DSC analysis revealed that the FSC had a melting and solidification temperature of 31.1 °C and 31.5 °C, respectively, and its melting and solidification enthalpy was 45.3 and 44.6 J/g, respectively. The 28-days compressive and flexural strength of the developed mortar were found as 28.94 MPa and 3.52 MPa, respectively. Thermal regulation performance test indicated that the average differences of the center temperatures between the standard cement mortar cell and the cement mortar cell containing FSC were 1.90 °C and 1.39 °C during heating and cooling stage, respectively. Consequently, the fabricated novel cement mortar produced with superior thermal and mechanical characteristics has a significant potential for the thermal regulation and energy conservation in buildings.