End-of-Life of building materials: innovative upcycling experiment for brick recovery

The construction sector is one of the major contributors to Greenhouse Gas emissions and waste generation in Europe, making the adoption of decarbonisation and circular economy strategies particularly urgent. In this framework, construction and demolition waste, such as clay brick and ceramic-based materials, accounts for a significant fraction of both mass and volume. Although the brick industry has already integrated circular practices into production by incorporating secondary raw materials, end-of-life brick waste is still mainly managed through downcycling practices, leading to a loss of material value. This paper presents an innovative approach to enhance the recovery of post-production and post-use brick waste through technological cross-fertilisation with the Autoclaved Aerated Concrete sector. The research, developed within the project ‘Circolarità delle risorse materiche’ and carried out in collaboration between academic institutions and industrial partners, investigates the feasibility of producing a lightweight, porous material from crushed brick waste. The experimental activity was organised into three sequential laboratory phases. The first two, based on traditional binders and AAC-like formulations, did not achieve satisfactory results due to issues such as sample fragmentation and disintegration. The third phase introduced a geopolymer-based approach, which resulted in cohesive specimens characterised by a widespread porous structure, with densities ranging from 700 to 950 kg/m3 and porosity values up to 68%. Preliminary results highlight the potential of the new material as a massive thermal insulation solution and as a component for wall cladding systems or suspended ceilings with sound-absorbing and hygrothermal regulation properties. Further performance testing and assessments of industrial scalability are currently ongoing, contributing to the development of new high-value circular pathways for end-of-life brick recovery.