Asphalt Modified with Biomaterials as Eco-Friendly and Sustainable Modifiers

High construction costs, when combined with awareness regarding environmental stew- ardship have encouraged the use of waste and renewable resources in asphalt modifi -cation. Increasing energy costs and the strong worldwide demand for petroleum have encouraged the development of alternative binders to modify or replace asphalt binders. The benefits of using alternative binders are that they can help save natural resources and reduce energy consumption while maintaining and in some cases improving asphalt performance. Common alternative binders include engine oil residue, bio-binder, soy- bean oil, palm oil, fossil fuel, swine waste, and materials from pyrolysis. Chemical compositions of the majority of these alternative binders are similar to those of unmodified asphalt binders (e.g. Resin, saturates, aromatics, and asphaltene). On the other hand, tests indicate the wide variability in the properties of alternative binders. Also, the chemi- cal modification mechanism for asphalt with alternative binders depends clearly on the unmodified asphalt and is consequently not well understood. For energy sustainabil - ity, environment-friendly materials and an urgent need for infrastructure rehabilitation that more research is needed to evaluate the alternative binders for use in asphalt modification. The alternative binders should have moisture resistance and good aging characteristics.