Investigation on the effect of high amount of Re-recycled RAP with Warm mix asphalt (WMA) technology

Di Wang,Chiara Riccardi,Babak Jafari,Augusto Cannone Falchetto,Michael P Wistuba

doi:10.1016/j.conbuildmat.2021.125395

Di Wang, Chiara Riccardi + Show 3 more

Open Access

https://doi.org/10.1016/j.conbuildmat.2021.125395

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Abstract

In this paper, the effect of the combined use of re-recycled Reclaimed Asphalt Pavement (RAP) on the performance properties of Warm Mix Asphalt (WMA) was experimentally investigated at both binder and mixture scales. First, a virgin 50/70 Pen Grade binder and fresh Gabbro aggregates were used to prepare a conventional Hot Mix Asphalt (HMA) for surface layers as a reference mixture. Then, the same reference mix type was used to produce a mixture designed with 40% of RAP, 160/220 Pen Grade binder, and Sasobit to prepare the first generation of Warm Mix Asphalt (WMA-1) mixture. Next, WMA-1 was artificially aged to simulate the re-recycled RAP, and the same mix design was adopted to prepare the second generation of WMA with re-recycled RAP identified as WMA-2. Finally, fatigue and low temperature performance of the mixture was evaluated for the three recycling level (reference, first and second recycling). In addition, rheological tests were conducted on the entire set of six asphalt binders used for the mix design, including virgin 50/70, 160/220 Pen Grade binders, extracted binders from RAP, WMA-1, artificial aged WMA-1, and WMA-2. Results of asphalt mixtures indicate that WMA-2 shows better low temperaure properties compared to the other two mixtures associated with limited reduction in the fatigue response. Concerning asphalt binders, similar rheological properties were observed within virgin 50/70, and two WMA extracted binders in a wide range of temperatures. The present study supports the idea of using re-recycled RAP up to 40% together with WMA technology in the mix design.

Highlights

In the attempt to globally achieve the climate-neutral goal, different technologies, materials, and methods have been proposed and evaluated in the pavement construction sector
The same reference mix type was used to produce a mixture designed with 40% of Reclaimed Asphalt Pavement (RAP), 160/220 Pen Grade binder, and Sasobit to prepare the first generation of Warm Mix Asphalt (WMA-1) mixture
The experimentation conducted in this series of research efforts has shown that RAP has the potential of being used for a second round of recycling up to a content of 40% in conventional Hot Mix Asphalt (HMA)

Summary

Introduction

In the attempt to globally achieve the climate-neutral goal, different technologies, materials, and methods have been proposed and evaluated in the pavement construction sector. In this sense, circular economy and resource efficiency have been seen as a roadmap to be adopted to improve the resilience of infrastructures while maximizing their asso ciated climate and economic benefits. WMA technology was proposed in the 1990 s to reduce the emission of greenhouse gas and develop environmentally friendly and sustainable transportation infrastructures [16,17] This tech nology can achieve performance comparable to the conventional HMA mixture with a reduction of production temperature of 20 ◦C to 40 ◦C [17]. In this paper, the potential of using these two technologies for pavement construction is experimentally studied

Objective and research approach

Asphalt mixtures

Asphalt binders

Experimental work

Summary and conclusion