Evaluating the High-Temperature Properties and Reaction Mechanism of Terminal Blend Rubber/Nano Silica Composite Modified Asphalt Using Activated Rubber

Nonde Lushinga; Zejiao Dong; Liping Cao

doi:10.3390/nano12244388

Evaluating the High-Temperature Properties and Reaction Mechanism of Terminal Blend Rubber/Nano Silica Composite Modified Asphalt Using Activated Rubber

Nanomaterials (Basel). 2022 Dec 9;12(24):4388. doi: 10.3390/nano12244388.

Authors

Nonde Lushinga^{1

2}, Zejiao Dong¹, Liping Cao¹

Affiliations

¹ Department of Road and Railway Engineering, School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090, China.
² Department of Construction Economics and Management, School of Built Environment, The Copperbelt University, Kitwe P.O. Box 21692, Zambia.

Abstract

Terminal blend (TB) rubberized asphalt is a popular technology in the production of rubberized asphalt. However, it always presents challenges regarding the inadequate high-temperature rutting performance of the binders. Additionally, crumb rubber (CR), a modifier of asphalt is a cross-linked material which presents poor compatibility between CR particles and bitumen. Incorporating nanomaterials and pretreating CR particles are two possible solutions to address this drawback. But the performance improvement and modification mechanism of the composite TB binders is not clearly understood. Therefore, the purpose of this research was to evaluate the high-temperature properties and reaction mechanism of the TB rubber/nano silica composite modified asphalt using microwave activated rubber. To achieve the research purpose, bitumen penetration grade 80-100 was first modified with 8% CR particles at elevated temperature to produce TB rubberized asphalt followed by the addition of 0.5, 1.5 and 3.0% weight percentage of nano silica to produce TB rubber/nano silica composite modified asphalt. Short and long-term aging tests were performed on samples by thin film oven test (TFOT) and pressure aging vessel (PAV) prior to chemical and rheological tests. The results of the study shows that nano silica has a great influence on the high temperature rutting resistance, storage stability and anti-aging properties of TB rubberized asphalt. Nano silica promoted good interaction and compatibility between CR particles and bitumen and improved the overall rheological properties of the binders. XRD test results revealed that the TB rubberized/nano silica composite modified asphalt samples were amorphous materials and did not have a crystalline structure. The reaction mechanism between rubber and asphalt was found to be physical, whereas nano silica interacted chemically with TB rubberized asphalt. In light of these findings, this research concluded that nano silica evidently improves the high-temperature rutting properties of TB rubberized asphalt, which deserves further exploration and application.

Keywords: microwave-activated crumb rubber asphalt; nano silica; rheology; storage stability; terminal blend (TB) rubberized asphalt.

Grants and funding

This research work was published with funding from the Copperbelt University, Africa Centre of Excellence for Sustainable Mining (CBU-ACESM) who generously covered the Article Publishing Charges (APC).