Effect of Biomass-Derived Biochar on Reactive Rejuvenated Styrene–Butadiene–Styrene-Modified Bitumen During Multiple Aging and Rejuvenation Cycles

Vollständiger Abstract

Worum geht es in dieser Arbeit?

Abstract Reactive rejuvenation can restore the bitumen phase and reconstruct the styrene–butadiene–styrene (SBS) phase in aged SBS modified bitumen (SMB). However, reactive rejuvenated SMB still undergoes repeated aging during service. To enhance the aging resistance of reactive rejuvenated SMB, biomass-derived biochar was incorporated into the reactive rejuvenator to develop a biochar-modified reactive rejuvenator (BRR). The effect of biomass-derived biochar on reactive rejuvenated SMB during multiple aging and rejuvenation cycles (MARC) was investigated through physical property test, rheological test, toughness test, SARA fraction analysis, fluorescence microscopy test, and molecular dynamics simulations. Results show that BRR can restore the compositional balance of the bitumen phase and reconstruct the SBS phase in aged SMB, but its rejuvenation efficiency gradually declines with increasing MARC cycles. The large specific surface area and porous structure of particulate biochar absorb and stabilize light fractions in rejuvenated SMB, thereby weakening their dispersion and solubilization effects on heavy fractions and increasing the relative proportion of heavy fractions. This strengthens the rutting resistance of reactive rejuvenated SMB at the expense of its deformation resistance and low-temperature cracking resistance. Biochar can improve the aging resistance of rejuvenated SMB by protecting the bitumen phase rather than the SBS phase. This protection is attributed to its ability to absorb and stabilize light fractions in rejuvenated SMB, which reduces their loss during multiple aging cycles and retards the transition of the bitumen phase toward a gel-like colloidal structure.