Feasibility of the use of ultrasound measurements for grade verification of the performance grade asphalt binders

This research investigates the feasibility of application of high frequency immersion ultrasonic measurement (UM) to discriminate different performance grade (PG) asphalt binders. PG asphalt binder is one of the main components of hot mix asphalt used for roadway construction. UT may provide an inexpensive alternative to sophisticated tests currently used for quality control of PG asphalt binders. Nine different PG asphalt binders used were selected for this investigation. Velocity (V) and integrated response (IR) of the ultrasonic wave were measured. The IR is a measure of the ratio of ultrasonic energy transmitted into the material to the ultrasonic energy reflected from the surface of material, in decibels. The physical properties of PG asphalt binders are temperature sensitive. Accordingly, the UM was performed at five temperatures. The results indicate that velocity decrease with increase in temperature of the asphalt binder. UT could distinguish between modified and non-modified asphalt binders. Discriminant Function Analysis was used to predict the grade of the performance grade asphalt binders using the UM.