The effect of active filler type, compaction method and slag-based geopolymer on volumetric and mechanical properties of cold foamed bitumen mixes with 100% RAP

Cold in-situ recycling with foamed bitumen has become one of the most cost-effective and sustainable technologies due to working with low heating energy, less transport, and decreasing the use of new materials. This paper presents a benchmark laboratory study of the volumetric and mechanical properties of cold recycled foamed bitumen mixes blended with 100% reclaimed asphalt pavement (RAP) in the granular base layer. The air void content, indirect tensile strength, and resistance to moisture damage are tested to evaluate the impact of active filler, compaction technique, and geopolymer. It was found that the addition of active filler, regardless of the type, increased the moisture resistance between 30% and 35% compared to the mixture with no active filler. Moreover, the addition of slag-based geopolymer resulted in a substantial increase in tensile strength from 434 kPa to 823 kPa while leading to a sharp decrease from 70% to 38% in moisture resistance.