Dehydration of fine concrete waste by microwave heating

To reduce the environmental impact of Ordinary Portland Cement (OPC) production, re-use of recycled concrete fines as a (partial) OPC-replacement could be considered. After a heat treatment in a temperature window of 400-800°C, most efficient dehydration of hydrated phases occurs, and new phases are formed (thermal activation). These dehydration phases have cementitious characteristics and can rehydrate upon contact with water, obtaining binding properties. In this research, the use of microwave (MW) technology to thermally activate hydrated cement paste in concrete waste is investigated. The goal of this project is to assess the influence of microwave irradiation on the dehydration of concrete fines, upscale and optimise the thermal activation of concrete waste from a lab-scale MW-system to a continuous industrial MW installation, and investigate the properties and hydraulic potential of the MW-activated material, with a focus on its compatibility with ground granulated blast furnace slag (GGBFS) and the use as (partial) cement replacement.