Research on Rheological Properties of High-Percentage Artificial RAP Binder with WMA Additives

Weiying Wang,Rui Dong,Yongchun Qin,Yiren Sun,Songchang Huang,Jingyun Chen

doi:10.1155/2020/1238378

Abstract

With the development of pavement recycling technology, the requirement of reclaimed asphalt pavement (RAP) is substantially increasing. Warm-mix recycled asphalt (WMRA) technology has made great progress, which can effectively decrease the working temperature and improve the RAP content. In this study, the rheological properties of recycled binders with incorporation of high-percentage artificial RAP binder (30–70%) were evaluated using two types of warm-mix asphalt (WMA) additives, i.e., polyethylene wax R and surfactant M. The dynamic shear rheometer (DSR) and beam bending rheometer (BBR) tests were conducted on the recycled binders. The results showed that the temperature and frequency played an important role in determining the complex shear modulus of the high-percentage WMRA binders. The dependency of phase angle on frequency increased after the long-term aging. The WMA additive R had a relatively huge impact on the rheological properties of asphalt, which mainly occurred before the PAV aging of recycled asphalt binder; the WMA additive M had no significant impact on the rheological properties of recycled asphalt binder. The WMA additive R enhanced the low-temperature rheology of recycled asphalt binder, while the WMA additive M enhanced the high-temperature rheology of recycled asphalt binder. Both of these types of WMA additives improved the antifatigue performance of recycled asphalt binder. The increased content of RAP binder improved the high-temperature performance and reduced the low-temperature performance of the recycled asphalt binder. However, it had no obvious impact on the fatigue performance. In addition, there was a good linear relation between the RAP binder content and the two indexes of the multiple stress creep recovery (MSCR) test.

Highlights

With the development of pavement recycling technology, the requirement of reclaimed asphalt pavement (RAP) is substantially increasing
It indicates that the addition of warm-mix asphalt (WMA) additive M has no remarkable impact on the viscoelasticity of asphalt. e complex shear modulus of WMA-R binder is less than that of the other two binders; there is no big difference in the phase angle in the low frequency region
(3) e performance of low-temperature crack resistance of recycled binders was reduced comparing with the 90# base asphalt, due to the addition of RAP binder. e low-temperature performance of the three types of recycled binders was ranked as RAP-R binder > RAP-M binder > control binder

Summary

Introduction

With the development of pavement recycling technology, the requirement of reclaimed asphalt pavement (RAP) is substantially increasing. Selecting appropriate recycling agent and accurately determining its content are able to improve the pavement performance of recycled asphalt mixture [16, 17] Those approaches mentioned above improved the content of RAP in the recycled mixture and provided guidance for the design and construction of asphalt mixture with high percentage of RAP, higher construction temperature will inevitably generate numerous emissions in the process of mixing and construction, which will still damage the environment and consume a large amount of energy. Based on the above considerations, numbers of researchers turned their attention to the WMA technology and attempted to add WMA additives into recycled asphalt mixture to reduce the construction temperature while increasing the RAP content. Based on the above considerations, numbers of researchers turned their attention to the WMA technology and attempted to add WMA additives into recycled asphalt mixture to reduce the construction temperature while increasing the RAP content. us, warm-mix recycled asphalt (WMRA) has been rapidly applied and promoted [18, 19]

Methods

Results

Conclusion