Valorization of bulk molding compound (BMC) waste in alkali-activated materials (AAMs) for paving applications: technical validation and life cycle assessment

The recycling of glass-fiber-reinforced thermosets represents a critical challenge due to their cross-linked polymeric matrix and high inorganic fraction, which limit the applicability of conventional end-of-life strategies. Thus, our work investigates an alternative recycling pathway based on the incorporation of milled BMC into Alkali-Activated Materials (AAMs), with the dual objective of exploiting BMC both as a partial substitute for fine aggregates and as an additional source of reactive aluminosilicates. Life cycle assessment (LCA) further highlights the environmental benefits of our strategy, showing a 76% reduction in single-score impacts compared to incineration and a 24% lower footprint of AAM-BMC paving blocks relative to conventional concrete alternatives. Beyond the specific case of paving applications, our study demonstrates a replicable framework for the valorization of complex thermoset composite wastes in BMC-based AAMs, contributing to the broader circular economy strategies in the construction sector in alignment with sustainable development goals.