Phase Change Materials in Cement Mortar for Enhanced Thermal Performance: A Review of Organic and Inorganic Systems

The increasing energy demand for heating, ventilation and air-conditioning has encouraged the development of construction materials capable of regulating indoor temperature passively. Phase change materials (PCMs) are promising thermal energy-storage materials because they absorb and release considerable latent heat during melting and solidification within a narrow temperature range. This review examines the incorporation of organic and inorganic PCMs into cement mortar and other cementitious building materials. Organic PCMs, including paraffins, polyethylene glycols, fatty acids and esters, provide chemical stability, negligible supercooling and compatibility with cement-based systems, but generally possess low thermal conductivity. Inorganic PCMs, particularly salt hydrates, offer higher volumetric heat-storage capacity, superior thermal conductivity and lower cost, although phase segregation, supercooling and corrosion may restrict their application. Incorporation techniques such as direct mixing, immersion, vacuum impregnation, macroencapsulation and microencapsulation are critically discussed. Previous studies demonstrate that PCM addition can reduce thermal conductivity, delay peak heat transfer and moderate indoor temperature fluctuations. However, PCM incorporation may increase porosity, cause leakage and moderately reduce compressive and flexural strength. The literature indicates that carefully selected PCM type, dosage and incorporation techniques can provide a satisfactory balance between thermal efficiency, mechanical properties and durability, supporting the development of energy-efficient and sustainable cementitious building components.