Measuring the Complex Modulus of Asphalt Concrete Using Ultrasonic Testing

Abstract

Dynamic modulus mastercurves are essential for the design and modeling of asphalt concrete (AC). One way of improving the accuracy of the upper asymptote of the mastercurve is to test at extremely high frequencies or extremely low temperatures. Ultrasound is used extensively in the nondestructive testing of materials and the work completed here demonstrates the potential for the application of this technology to AC. Since testing at extremely low temperatures is not practical, a new ultrasonic technique is developed for measuring the complex moduli of AC. A theoretical explanation of the measurement process is provided. Two AC specimens were tested using the ultrasonic method and the dynamic modulus method in the indirect tensile test (IDT) mode. Both test techniques were performed at four different temperatures. The mastercurves were constructed using time-temperature superposition on the IDT test data and the upper asymptotes were extrapolated. The ultrasonic data was shifted to the desired reference temperature and the predicted moduli were compared to those of the IDT test. It was found that the moduli predicted using the ultrasound measurement agreed well for the specimen with a lower air-void content and differed more for the specimen with a higher air-void content. The phase angles predicted by the ultrasonic method were higher than those obtained from the IDT test. It is believed that this was a result of wave scattering from air-voids and aggregates. Suggestions are made to further increase the accuracy of the technique.

Damage Detection of Asphalt Concrete Using Piezo-Ultrasonic Wave Technology

“…Compared with other studies, the ultrasonic velocity is lower than 3000 m/s in ambient [21,22,23,24,25]. Based on the impact analysis, it reveals that the ultrasonic velocity is the result of the combined effect of temperature, environment condition and service time.…”

“…The application of ultrasonic testing technology is in the rock and cement concrete materials [18,19] but the application in asphalt mixture is not as many [20,21,22,23,24,25]. The research is still in the exploratory stage, such as the relationship between ultrasonic velocity and airvoid, elastic modulus, fatigue life and so on.…”

A New Method of Designing Electrical Impedance Matching Network for Piezoelectric Ultrasound Transducer

“…TPG ω = (2) Each topology of the initial population is created randomly and the population size we use here is 120.…”

“…Piezoelectric transducers have been widely applied in different fields [1] [2]. Most of traditional piezoelectric transducers are narrowband which can only produce large scale vibration within a narrow range of resonant frequency.…”

Backcalculation of Asphalt Concrete Poisson's Ratio using the Ultrasonic Pulse Velocity Test

“…[13] evaluated filler content, binder content, as well as compaction level by applying the UPV technique. Material properties, including strength [14], modulus [8,15], and Poisson's ratio [16] of construction materials can be measured or related by UPV. Commonly, the ASTM C597 standard [17] is used to perform concrete and asphalt modulus tests using UPV [8,18,19] When using the ASTM standard to predict the modulus of asphalt concrete, PR is necessary to be assumed for various temperatures [8,20].…”