Dry-Process Polymer Toughening of High-Modulus Asphalt Mixtures: Rheological Response and Competitive Absorption
Year: 2026
Type: article
Abstract: High-modulus asphalt mixtures (HMAMs) achieve high stiffness but exhibit insufficient resistance to low-temperature cracking. To balance high- and low-temperature performance, HMAMs containing 0.3%, 0.6%, and 1.0% high-modulus modifier (HMM) were toughened with a styrene–butadiene-based polymer (SBP) through a dry process. The toughening behavior and mechanisms were investigated at different SBP dosages (0.2%, 0.4%, and 0.6%) and conditioning times using mixture tests, binder rheological characterization, individual and co-swelling tests, and molecular dynamics simulations. Increasing HMM content substantially improved dynamic modulus and rutting resistance but continuously reduced low-temperature bending strain. At 0.4%, SBP provided favorable strength–deformation compatibility, increasing bending strain by 76.1%, 75.3%, and 63.2% in the three HMM systems, respectively. The optimal conditioning time extended from 30 min (0.3% HMM) to 60 min (0.6% and 1.0% HMM). The 0.6% HMM–0.4% SBP combination exhibited the most balanced overall performance. Rheological results showed that HMM enhanced high-temperature elasticity, whereas SBP reduced low-temperature creep stiffness and improved stress relaxation. With limited availability of light fractions, increasing HMM from 0.3% to 1.0% reduced the swelling ratio of SBP from 114.87% to 62.30%. Molecular simulations further showed that HMM–light fraction interactions increased, whereas the magnitude of the SBP–light fraction interaction energy decreased by 13.2%. These findings suggest that competition for limited light fractions may contribute to the HMM-dependent toughening response, providing a basis for further investigation of material composition and conditioning requirements.
Source: Polymers
Institution: Southeast University
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,258
OpenAlex ID: W7225630992