Laboratory Study on CR/SBS Modified Asphalt: Preparation and Performance Characterization

Abstract

Crumble rubber (CR) can be used to prepare CR and styrene-butadiene-styrene (SBS) composite modified asphalt with a good high-and low-temperature performance, meanwhile the addition of CR could work as the substitute for SBS and help reduce the content of SBS. This study contains three main parts: effect of preparation and effect of material composition as well as rheological performance characterization. Factors during the preparation, including shearing temperature, shearing time, mixing time and swelling time, were selected, while base binder, CR content, CR particle size and SBS content in material composition were considered. The effects of these factors were assessed in terms of the conventional performance (penetration, softening point, ductility and storage stability). After identifying these effects, the sample of CR and SBS modified asphalt at the selected preparing condition and material composition (CR/SBSMA) was made, and the corresponding SBS modified and CR modified asphalt (SBSMA and CRMA) were produced for the comparing reason. Subsequently, temperature sweeps from 0°C to 80°C were utilized to depict the viscoelasticity of these modified asphalt binders by complex modulus and phase angle. Multiple stress creep recovery tests (MSCR) at 64°C and bending beam rheometer tests (BBR) at various low temperatures were employed to evaluate the high-and low-temperature performance, respectively. Results highlight that that CR/SBSMA could exhibit an excellent high-temperature performance (better than SBSMA), and a good low-temperature performance (reaching the level of base binder).

Study on Properties and Micro-Mechanism of RHB-SBS Composite-Modified Asphalt

“…The content of SBS substituted by rubber powder is limited, and it is unclear whether toxic sulfide is generated when sulfur is added to SBS composite-modified asphalt. To reduce the content of SBS in asphalt, Song [ 4 ] et al studied the feasibility of replacing part of SBS with crumb rubber (CR) to improve the high- and low-temperature performance of asphalt. The results showed that the higher the temperature and longer the time during the preparation of CR and SBS composite-modified asphalt, the better the high-temperature performance, but the increase in temperature and time would be detrimental to the low-temperature performance.…”