Life‑cycle analysis of bio‑based phase change materials in recycled‑aggregate mortars: sourcing sensitivity and trade‑offs

Abstract The decarbonization of construction materials requires circular design strategies supported by life‑cycle thinking. This study quantifies the cradle‑to‑gate (A1–A3) environmental impacts of three mortar formulations: (i) a Reference mortar, (ii) a mortar incorporating recycled wood aggregates, and (iii) a hybrid mortar in which recycled wood aggregates are impregnated with a bio‑based phase change material to provide latent‑heat storage functionality. A Life Cycle Assessment compliant with ISO 14044 and EN 15804 was implemented in SimaPro using Ecoinvent, focusing on fossil embodied greenhouse-gas emissions (IPCC GWP100a) and total Cumulative Energy Demand (CED). For a performance-related material-scale comparison, results were additionally normalized by volumetric thermal capacity. Because a dedicated inventory for the commercial bio‑based phase change material (PureTemp 25) is not publicly available, a scenario‑based sensitivity analysis was performed using four alternative feedstock proxies (coconut, palm, palm kernel, and Reference mortar has the lowest GWP soybean). Each feedstock was modeled separately, and the unweighted arithmetic mean of the four scenario results was used as a representative central estimate; this value does not represent a physical or equal-proportion mixture of oils. On this basis, replacing conventional constituents with recycled alternatives reduced impacts substantially, reaching up to 82% lower IPCC GWP and 36% lower CED for the hybrid mortar compared with the conventional reference. Feedstock choice strongly influenced trade‑offs, particularly land use and water consumption, highlighting the importance of responsible sourcing for bio‑based components. The results provide decision‑support evidence for the sustainable design of circular, functionality‑enhanced building materials.