Investigation on rheological characteristics of low-emissions crumb rubber modified asphalt

ABSTRACT

Asphalt modified by microwave-treatment crumb rubber (CR-microwave) and that of deodorant-addition crumb rubber (CR-deodorant) have low unfavorable or detrimental emissions, but their high- and low-temperature performances have been insufficiently researched, potentially limiting their application and promotion. In order to investigate high-temperature performances of the two low-emissions crumb rubber modified asphalt (CRMA), viscosity, temperature ramp, creep and creep recovery and amplitude sweep tests were conducted using Brookfield Viscometer and dynamic shear rheometer (DSR). Also, low-temperature performances of CMRA were characterised by bending beam rheometer (BBR) tests. Results showed that deodorant-addition CR with a high dosage is not allowed considering asphalt workability, but microwave-treatment CR with various dosages can still meet workability requirements. Moreover, the introduction of microwave-treatment CR or deodorant-addition CR into asphalt improved high-temperature performances of asphalt, while the former had lower positive effects on high-temperature performance grades, elastic recovery and deformation resistance of asphalt. Furthermore, like common CRMA, the two low-emissions CRMA had different viscoelastic behaviour from styrene–butadiene-styrene copolymer (SBS) modified asphalt. Additionally, 18% CR-microwave or CR-deodorant can basically improve the low-temperature performance grades of asphalt. Comprehensively considering the workability and high- and low-temperature performances of the two low-emissions CRMA, 18% CR-microwave is recommended for low-emissions CRMA manufacture.

KEYWORDS:

• Low-emissions crumb rubber modified asphalt
• microwave-treatment crumb rubber
• deodorant-addition crumb rubber
• viscosity
• high-temperature rheological properties
• low-temperature performance grade

Acknowledgments

This work was supported by Hunan Provincial Natural Science Foundation of China (grant number 2022JJ30155), the Huxiang Youth Talent Program of Hunan Province (grant number 2019RS2052), the Postgraduate Scientific Research Innovation Project of Hunan Province (grant number CX20210412), the Transportation Science and Technology Development and Innovation Project of Hunan Province (grant number 201805), the Science and Technology Planning Project of Hunan Province (grant number 2018TP2038), the China Scholarship Council (grant number 201806130114). The authors gratefully acknowledge their financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by China Scholarship Council: [Grant Number 201806130114]; Transportation Science and Technology Development and Innovation Project of Hunan Province: [Grant Number 201805]; Postgraduate Scientific Research Innovation Project of Hunan Province: [Grant Number CX20210412]; the Science and Technology Planning Project of Hunan Province: [Grant Number 2019XF5036, 2018TP2038]; Huxiang Youth Talent Program of Hunan Province: [Grant Number 2019RS2052].