Investigation on Rheological Properties and Storage Stability of Modified Asphalt Based on the Grafting Activation of Crumb Rubber.

Zheng Zheng,Zhu Zhu,Yang Yang,Zhang Zhang,Xie Xie,Lv Lv

doi:10.3390/polym11101563

Abstract

Acrylamide with a double bond and amide group can not only copolymerize with macromolecules of crumb rubber but also react with acidic groups in asphalt, so it was selected as a modifier to activate crumb rubber through chemical graft action. The purpose is to improve the compatibility between crumb rubber and asphalt and thus improve the rheological properties and storage stability of rubber asphalt. Infrared spectroscopy (IR) and scanning electron microscopy (SEM) were used to characterize the crumb rubbers and their modified asphalt. It was found that the crumb rubber of grafting acrylamide had better compatibility in asphalt due to its larger specific surface area and chemical reaction with asphalt. In addition, the high temperature rheological test, low temperature creep test, and polymer separation test were carried out to study the effect of grafted activated crumb rubber on the properties of modified asphalt. The results showed that compared with modified asphalt with common crumb rubber (CRMA), the rheological properties and storage stability of modified asphalt with grafting activated crumb rubber (A–G–R) were improved significantly. The results of microscopic and macroscopic tests show that the activated rubber particles have a larger contact area with asphalt due to a rougher surface and the chemical cross-linking between rubber particles and asphalt further strengthens their interaction. Therefore, there is a relatively stable blend system formed in modified asphalt, and its performance of modified asphalt has been improved.

Highlights

Waste tires will become solid waste after aging, mechanical wear, and scrapping
Xue et al [19] wrapped rubber modified asphalt with steel slag powder by granulation machine and prepared compound modified asphalt, and the results showed the softening point differences decreased to 2.1 ◦ C
It can be seen that there were three new absorption peaks in the infrared absorption spectrums of AM–crumb rubber (CR) compared with that of CR, including the absorption peak at cm−1 caused by the stretching vibration of –NH2 [32], the absorption peak at cm−1 and 1600 cm−1 caused by the stretching vibration of –NHCO– [3], while these new chemical bonds are derived from acrylamide

Summary

Introduction

China’s scrap tire production has ranked first in the world for ten consecutive years and is expected to reach 20 million tons by 2020 [1]. Traditional treatment methods such as incineration, landfill or simple accumulation will occupy land resources, and release harmful substances, pollute soil and groundwater, which will endanger human survival [2,3]. A lot of modified asphalts are prepared to meet the modern transportation requirements for asphalt materials [9]. Crumb rubber modified asphalt has attracted wide attention because of good comprehensive performance

Methods

Results

Conclusion