Abstract

Waste tyres (WTs) represent a significant challenge in recycling and disposal, given their high generation rate and low degradability under environmental conditions. One of the promising alternatives for recovering WTs is their thermal fractionation by pyrolysis. This way, multifunctional liquids that can improve the rheological and self-healing properties of aged asphalt binders are obtained. This research uses WT mixtures from light vehicles (WT-L) and mining trucks (WT-M) to produce asphalt rejuvenators through pyrolysis technology. Then, the rejuvenator was optimised by thermal fractionation via distillation to create an improved pyrolytic rejuvenator (PR) to improve the rheological and self-healing properties of aged bitumen. The effect of different doses of PR (3%, 6%, and 9%, by weight of asphalt binder) on the rheological properties of the bitumen at different ageing levels was measured by frequency-temperature tests in a DSR device. Main results showed that the rejuvenator obtained by pyrolysis at 465 degrees C and distillation cut-off between 160-200 degrees C contains aliphatic hydrocarbons and aromatic families, with a significant proportion of terpenes (similar to 34%). It was also proven that the incorporation of PR-1, in doses between 3% and 6%, positively affected the restoration of the rheological properties of PAV samples up to a primary ageing state. To conclude, the optimised pyrolytic rejuvenator can successfully restore aged asphalts, making it a potential agent to promote more durable and sustainable asphalt pavements.