Environmental Impact on VOCs Emission of a Recycled Asphalt Mixture with a High Percentage of RAP.

Minghua Wei,Shaopeng Wu,Na Li,Lei Zhu,Chao Yang

doi:10.3390/ma14040947

Abstract

Recycling of reclaimed asphalt pavement (RAP) has gradually emerged as a hot topic in the current research of building materials. Manufacturing the recycled asphalt mixture with a high RAP content still remains a major challenge due to the problem of inferior water damage resistance and fatigue cracking resistance. The aim of this study is to evaluate the servicing performance of recycled asphalt mixture with high percentage of RAP and assess its environmental impact on volatile organic compounds (VOCs) emission. To further explore the intrinsic factor on the performance of a recycled asphalt mixture, the mixed asphalt binder with a different content of extracted RAP binder was firstly investigated. The results show that the larger the content of RAP binder, the lower the mechanical indexes and VOCs emission. There exists an internal relationship between the chemical composition and VOCs release behavior with the variation of the recycled asphalt binder content. Based on the results of mixed recycled asphalt binder, the road servicing performance of a rather high utilization of RAP (i.e., 50%, 60%, and 70%) was assessed. It was found that the reuse of RAP aggregates has little influence on the volume performance of recycled asphalt mixture, and servicing performances still meet the construction requirements in spite of a descending trend. Moreover, a significant reduction effect on VOCs emission was found in the mixing stage of recycled asphalt mixture, indicating that the VOCs emission can be decreased by 94.82% when the content of RAP aggregates increases to 70%. The recycling of RAP with a high content contributes to the sustainable development of road engineering and the construction of green pavements.

Highlights

With the rapid development of the economy and society, China’s pavement construction has undergone earth shaking changes
SBS asphalt binder, recycled asphalt binder and mixed asphalt binder with different proportions (40%, 50%, 60%, 70% and 80%) were selected as the research objects, which were named as SBS, R, R-40%, R-50%, R-60%, R-70% and R-80%, respectively
The results show that SBS asphalt binder releases the largest number of volatile organic compounds (VOCs) at 11.15 mg/m3, while the recycled asphalt binder R released the least VOCs with a concentration of

Summary

Introduction

With the rapid development of the economy and society, China’s pavement construction has undergone earth shaking changes. Roads infrastructure has changed from being construction oriented to focusing on both construction and maintenance. Due to advantages of smooth surfaces, comfortable driving conditions and convenient maintenance, asphalt pavement has become the main form of pavement in China, accounting for more than 80% of the total pavement area [2]. Milling the original existing pavement surfaces and paving the new asphalt pavement is the most common form of maintenance treatment for asphalt pavement, producing a lot of waste asphalt mixture which causes environmental pollution. It has been reported that the cost of asphalt mixture production can be reduced from 70 US dollars per ton to 50 US dollars per ton by adding 50% RAP, which can even be reduced by 50–70% when the reuse of RAP reaches

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Results

Conclusion