Evaluation of Anti-Aging Effect in Biochar-Modified Bitumen

Abstract

Increasing environmental awareness has led to a great research effort towards the formulation of increasingly sustainable road pavements, mainly by developing bituminous mixtures incorpo-rating waste materials. Furthermore, some waste materials have been proved to be useful for enhancing the performance of road bitumen and bituminous products, so their use is a potential solution for ensuring environmental, economic and also technical benefits. Amongst the differ-ent wastes to be used for bitumen modification, a possible one is that obtained by pyrolysis of biomass, named biochar. In the research reported on here, a selected biochar was added to bi-tumen to verify the possibility of improving bitumen performance in terms of photo-oxidation resistance, which is a major problem in urban areas where black flexible pavements contribute to the urban heat island effect. Different biochar amounts were selected, and two different aging methods were performed: short-term aging and UVB aging behaviour; they were monitored through dynamic shear rheometry and Attenuated Total Reflectance-Fourier Transformation In-fraRed spectroscopy (ATR-FTIR). The structural changes in bitumen in terms of carbonyl and hydroxyl accumulation were monitored at different UV exposure times. All the experimental re-sults suggest that the use of biochar is able to produce a positive effect on the UV aging re-sistance of bitumen, reducing its photo-oxidation tendency.