Reuse of recycled asphalt pavement and mineral sludges in fluidized thermal backfills

The main purpose of the study described in the paper was to explore the possible use of recycled materials, such as Reclaimed Asphalt Pavement (RAP) and mineral sludge, in self-levelling and self-compacting Fluidized Thermal Backfills (FTBs). The assessment was performed by considering FTB mixtures containing different percentages of RAP and mineral sludges of three different types. Tests carried out in the laboratory focused on flowability, thermal conductivity and thermal stability. It was observed that all prepared FTBs exhibited satisfactory flow properties, with the occurrence of bleeding and segregation phenomena only when employing certain sludges in combination with excessive water content. Thermal conductivity of the FTBs was also found to be satisfactory and was observed to be significantly affected by cement content, RAP dosage, water-to-powder ratio and sludge type. Finally, thermal stability of the mixtures was checked in order to understand their behaviour in critical exposure conditions