Effect of liquefied food waste on asphalt mixture performance

Abstract

Considerable environmental concern regarding increased food wastage caused by population and economic growth has been raised worldwide. Thus, determining an alternative food waste recycling method for construction purposes is a challenge. This research evaluates a liquefied bio-product recovered from the hydrothermal liquefaction of food waste as a potential non-petroleum-based binder in asphalt pavement. Numerous parameters were evaluated to optimize the liquefaction reaction for the enhancement of the liquefied food waste (LFW) product recovered from the process. Next, LFW was used to substitute various portions of conventional asphalt binders 60/70 PEN (i.e., 5%, 10%, 15%, 20% and 30%) from the total binder weight. Then, their storage stability, physical, and rheological properties were assessed. Chemical properties, thermal decomposition, functional groups, and surface morphology analysis for LFW, conventional and modified asphalt binders were also determined. LFW provides the asphalt binder with improved rheological properties reflected by the enhanced rutting resistance for the modified asphalt binder with high performance grade. The FT-IR spectra of the LFW modified asphalt binder showed no new peak which indicates no chemical reaction occurred between asphalt binder and LFW. Morphological analysis revealed the presence of LFW boosted the quantity of heteroatoms and the polarity of the asphalt binder, which in turn is responsible for enhancing the adhesion properties between asphalt binder and aggregate. In addition, LFW asphalt mixture recorded featured performance for the creep resistance, which appeared by the highest creep stiffness with low permanent deformation as compared to the conventional mixture. This supported by the lower rutting depth measured for the modified samples compared to the conventional sample. Overall, the findings show that the LFW modified asphalt meets the standards specified for paving material and the environmental impact requirement.