Evaluation of optimized bio-asphalt containing high content waste cooking oil residues

- A new bio-asphalt containing high content WCOR (33.3% by weight) was obtained.
- Bio-asphalt with high WCOR content shows excellent mechanical and chemical performance.
- Bio-asphalt with high WCOR content has a promising application in the road industry.

Waste cooking oil residues (WCORs)-based bio-asphalt is a potential substitute for petroleum asphalt. However, asphalt binders with a high WCOR content indicates a low rheological property, leading to a limited WCOR mixed content (usually no more than 10 wt% of asphalt binder). This study aims to prepare an eco-friendly bio-asphalt with a high WCOR content. Based on the formula uniform design method, the optimum blending proportion of the bio-asphalt was determined as 33.3% WCOR, 31.8% hard asphalt particles (HAP), 30.3% hydrocarbon resin (HR1), 4.6% recycled low density polyethylene (R-LDPE), and external 4% linear SBS polymer (L-SBS). Rheological test results indicated that the optimized bio-asphalt (OBA) presented similar high-temperature performance to SBS modified asphalt (SBS-MA), and much better low-temperature performance than both of SBS-MA and PEN 70 base asphalt (PEN 70). Fourier transform infrared spectroscopy (FTIR) test proved that OBA had some special chemical composition such as the acids and esters originated from the addition of WCOR. On the basis of mixture performance tests, it confirmed that OBA mixture possessed similar rutting resistance and moisture susceptibility to SBS-MA mixture, and showed more satisfying low-temperature capability than both of SBS-MA mixture and PEN 70 mixture. Additionally, OBA mixture showed prominent fatigue performance since it had the highest fatigue life and stable fatigue sensitivity at different strain levels. All above evaluations imply the feasibility of using high content of WCOR in road construction applications since OBA containing 33.3% WCOR shows excellent binder and mixture performance.

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