Performance Enhancement of Permeable Asphalt Mixtures With Recycled Aggregate for Concrete Pavement Application

Bin Lei,Vivian W Y Tam,Wenkui Dong,Zhiyu Luo,Wengui Li,Kejin Wang

doi:10.3389/fmats.2020.00253

Abstract

The incorporation of recycled concrete aggregate (RCA) in permeable asphalt mixtures (PAM) is an efficient method of utilizing construction demolished waste. It not only conforms to the trend of building sponge cities, but also alleviates the problem of overexploitation of natural aggregate resources. As the performance of PAM containing recycled aggregate is not comparable to natural aggregate, modification treatments and hybrid fibers addition are adopted as two enhancement methods to improve the performance of PAM with RAC in this study. It is found that replacing natural aggregate with recycled aggregate increases the optimum asphalt content but decreases the residual stability. The optimum asphalt content is increased by 45% when the RCA ratio is 100%, whereas applying silicone resin can gives a 16.2% decrease in the optimum asphalt content. Enhancing RCA with silicone resin can increase the water stability to be comparable with natural aggregate. Moreover, with modification treatment using calcium hydroxide solution, the mechanical strength of PAM is enhanced to even higher than that only with natural coarse aggregate mixture. Improvements in both mechanical strength and water stability are also achieved by strengthening recycled aggregate with cement slurry, although the performance is less effective than using silicone resin. With the increase in the content of RCA, the permeability coefficients of PAM first decrease and then exhibit an increasing trend. The results indicate that the PAM with RCA and modification treatments can perform satisfactorily as a pavement material in practice. Applying probable modification, PAM incorporating RCA meets the criteria for use in concrete pavement applications.

Highlights

With the rapid development of the global economy, colossal amounts of waste have been generated by burgeoning populations, expanding industries, and tremendous urban growth
The purpose of this study is to explore the engineering properties of modified permeable asphalt mixtures (PAMs) with recycled concrete aggregate (RCA), which is strengthened by two methods: (1) impregnating the RCA with three types of solutions including cement slurry, silicone resin emulsion, and a saturated calcium hydroxide solution, and (2) adding two types of fibers to asphalt: polyester and basalt
The results show that the optimum asphalt content (OAC) increased about 20–45%, and the cost of using RCA in PAM increased as compared with using normal aggregates

Summary

Introduction

With the rapid development of the global economy, colossal amounts of waste have been generated by burgeoning populations, expanding industries, and tremendous urban growth. Approximately 2 million tons of concrete wastes are generated annually in China (Xiao et al, 2012). The global construction and demolition waste reached more than 3.0 billion tons annually. Permeable Asphalt Mixtures and is increasing constantly (Akhtar and Sarmah, 2018). Handling such a large amount of waste has become a serious problem. Recycling construction waste as aggregates to address the demand for natural sand and gravel has become an effective method of concrete waste disposal. Green production of cement concrete or asphalt concrete using recycled concrete aggregate (RCA) can reduce construction costs, eliminate environmental pollution, and mitigate natural aggregate depletion (Bru et al, 2014; San Nicolas and Provis, 2015; Kareem et al, 2018; Fernández-Jiménez et al, 2019; Chen et al, 2020)

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Conclusion