Laboratory Evaluation of the Performance of Bio-Binders in Conjunction with WMA & RA

One recent low carbon technology which has the potential to reduce the carbon footprint of asphalt is the use of biogenic binders. To fully realise the potential of bio-binders and to achieve net zero it is recognised that there is a need for bio-binders to be compatible with warm-mix asphalt and reclaimed asphalt. A laboratory investigation was therefore undertaken to assess the performance of a commercially available bio-binder in conjunction with Reclaimed Asphalt (RA) and Warm-Mix Asphalt (WMA). In total four mixes were assessed incorporating incremental changes to examine the performance of the bio-binders with warm-mix additives and increasing RA content (up to 20% RA). Performance testing was conducted on the binders, bituminous mixtures and recovered binder properties. This paper presents the results of the bituminous mixture testing and concludes the mixes incorporating a Polymer Modified Binder (PMB) bio-binder in conjunction with WMA and up to 20% RA has demonstrated comparable performance to the control surface in terms of wheeltracking, water sensitivity, cantabro abrasion loss, fracture toughness and fatigue. The only significant difference observed was in relation to the ITSM for the RA mixes, which is attributed to the RA content. Carbon footprint analysis has also confirmed that combination of bio-binders in conjunction with 20% RA and WMA can deliver significant carbon reductions.