Effect of Rejuvenators on the Workability and Performances of Reclaimed Asphalt Mixtures.

Wei Tang,Zhongyuan Wang,Fuqiang Dong,Yu Zhang,Ning Li,Xin Yu

doi:10.3390/ma14216385

Wei Tang, Zhongyuan Wang + Show 4 more

Open Access

https://doi.org/10.3390/ma14216385

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Abstract

The use of rejuvenators has enhanced the workability of asphalt mixtures containing the reclaimed asphalt pavement (RAP). This conclusion is based on the determination of viscosity of asphalt binders, while not validated from reclaimed asphalt mixtures. In this study, the effect of two rejuvenators (ordinary and emulsified rejuvenator) on the workability of reclaimed asphalt mixtures was evaluated by measuring the mixing torque and determining the air void content of reclaimed mixtures. In addition, their effects on the performances of reclaimed mixture were studied via the three indexes tests, rutting test and freeze-thaw splitting tests. The experimental results show that mixing torque and air void content of reclaimed mixtures with the emulsified rejuvenator is 4% and 6% lower than that with the ordinary rejuvenator, respectively. This indicates that improvement of the workability of reclaimed mixtures can be achieved by using an emulsified rejuvenator, but not by an ordinary rejuvenator. That is also the reason that at least 20% greater high-temperature stability is found for reclaimed mixtures by using the emulsified rejuvenator than using the ordinary rejuvenator. In addition, reclaimed mixtures with the emulsified rejuvenator show similar moisture susceptibility to that with the ordinary rejuvenator. This study provides a feasible method to assess the workability effect of rejuvenators on reclaimed mixtures directly and recommends the use of an emulsified rejuvenator to improve the workability and high-temperature stability of reclaimed mixtures.

Highlights

The growing attention devoted to environmental conservation and sustainable development, and the utilization of nonrenewable resources, such as oil and minerals, has been limited gradually [1]
The asphalt mixtures mixed with reclaimed asphalt pavement (RAP) are prone to yield fatigue failure and low temperature cracking [7]
Some researchers and engineers recommended using a softer virgin asphalt to recover the properties of aged asphalt to the level that resembles that of virgin asphalt [8,9]

Summary

Introduction

The growing attention devoted to environmental conservation and sustainable development, and the utilization of nonrenewable resources, such as oil and minerals, has been limited gradually [1]. That results in the continuous rise in the price of asphalt and aggregates [2]. In China, nearly 790 million tons of reclaimed asphalt pavement (RAP) is produced every year [3,4]. After good regeneration and appropriate mix design, RAP can substitute for the partial asphalt and aggregate in asphalt mixtures [5]. The use of RAP has gained more and more popularity due to its environmental and economic benefits [6]. The binder in RAP, is highly stiff and viscous after its service life [1]. The asphalt mixtures mixed with RAP are prone to yield fatigue failure and low temperature cracking [7]. Some researchers and engineers recommended using a softer virgin asphalt to recover the properties of aged asphalt to the level that resembles that of virgin asphalt [8,9]

Methods

Results

Conclusion