Open Access

ARTICLE

Mechanism behind Time Dependent Elasticity of Crumb Rubber-Nano-Asphalt Hybrids Using Discrete Relaxation Spectrum

Lili Han^1,2, Mulian Zheng^2,*, Hongbing Guo¹, Tao Wang³, Jiajian Zhu⁴, Pouria Hajikarimi⁵

1 Shaanxi College of Communication Technology, Xi’an, 710018, China
2 Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, Xi’an, 710064, China
3 Huabang Construction & Investment Group Co., Ltd., Guangzhou, 510030, China
4 Gansu Road and Bridge Construction Group Co., Ltd., Lanzhou, 730000, China
5 Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, 1591634311, Iran

* Corresponding Author: Mulian Zheng. Email:

(This article belongs to the Special Issue: Current Advances in Green Nanomaterials Applications)

Journal of Renewable Materials 2022, 10(6), 1727-1752. https://doi.org/10.32604/jrm.2022.018467

Received 30 July 2021; Accepted 08 September 2021; Issue published 20 January 2022

Abstract

Crumb rubber powder is a successfully used renewable material obtained from waste tire rubber, which has been incorporated into paving asphalt since the 1930s due to its good resistance to deformation and fatigue as well as its eco-friendly performance. In this study, carbon nanotubes and nano silica were incorporated into the terminal blend crumb rubber modified asphalt technology to remedy the issues of excessive desulfurization and degradation of ground tyre rubber with this technology. The mechanism behind the high temperature delayed elastic properties of the crumb rubber-nano-asphalt hybrids was experimentally investigated based on discrete relaxation spectrum. Development of the discrete relaxation spectra was accomplished by fitting on the 60°C storage modulus data tested by the dynamic shear rheometer using the generalized Maxwell model. Subsequently, the feasibility of characterizing delayed asphalt elasticity using main relaxation time was verified by test results from the 60°C creep and recovery test. Results indicated that the crumb rubber-nano-asphalt hybrids exhibited arrheodictic behavior and the asphalt elasticity was strengthened by two nano agents. Moreover, the elasticity reinforcement with carbon nanotubes was greater than with nano silica. Additionally, a good correlation was observed between the 60°C zero shear viscosity and main relaxation time, and greater 60°C zero shear viscosity was correlated to longer main relaxation times. Furthermore, longer main relaxation time of the asphalt was related to greater average recovery rate in the creep and recovery test. This research is expected to shed some light on the mechanism behind time-dependent elasticity of crumb rubber modified asphalt from the perspective of polymer physics.

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