Comparing effects of biobinder with other asphalt modifiers on low-temperature characteristics of asphalt

This paper examines effects of a new biobased modifier, "biobinder," on low-temperature properties of asphalt binder and compares the results with those of conventional modifiers: crumb rubber, Gilsonite, styrene-butadiene-styrene (SBS), and polyphosphoric acid (PPA). Low-temperature characteristics of modified and nonmodified asphalts were studied using experimental and modeling approaches. A three-point bending beam rheometer was used to measure the stress-strain response of each specimen. A theoretical approach was used to determine stiffness and stress release rate; in addition, the Burgers model was implemented to predict the stored and dissipated energy ratio and quantity of derivation of creep compliance in each of modified and nonmodified asphalt specimens. Effects of various modifications were compared based on both the calculated stored and dissipated energy ratio and quantity of derivation of creep compliance. The proposed biobinder is produced from the thermochemical conversion of biomass (including animal waste, switch grass, and woody biomass). Biobinder is then blended with virgin binder to produce biomodified binder (BMB). This paper argues that the improved low-temperature rheological properties in biomodified binder is reflected in the enhancement in energy dissipation ratio and quantity of derivation of creep compliance.