Property changes of SBS modified asphalt binders during short-term aging and implications on quality management

Abstract

Styrene-butadiene block copolymer (SBS) is a widely used as a modifier for improving asphalt binder properties. However, due to the lack of understanding on binder property changes during aging and sample preparation, quality control and quality assurance (QC/QA) measures are seldom applied to SBS modified asphalt binders in pavement mixtures. In this study, neat and SBS modified binders were aged at different conditions and durations, and solvent extraction and recovery (E&R) were performed on a portion of binder samples. The process of aging and E&R is to simulate asphalt mixture aging in production and construction and the retrieval of asphalt binders for QC/QA, respectively. The effects of binder aging and solvent E&R on binder quality characteristics were systematically examined, including infrared spectrum, rutting parameter, and phase angle obtained from oscillation shear, and non-recoverable creep compliance (Jnr) and percent recovery from multiple stress creep recovery (MSCR) tests. The results reveal the trends of changes in those binder characteristics in response to aging time, aging condition, and the E&R process. The mechanisms behind the trends and their implications on QC/QA are also discussed. It is anticipated that the findings of this paper contribute to the development of reasonable QC/QA measures for SBS modified asphalt in construction.