Impact of Specimen Geometry on Dynamic Modulus Measurement Test Setup

Abstract

A new mechanistic-empirical pavement design guide to better predict the service life of pavement systems is in its final stages of validation. One of the new input parameters recommended for the design is the dynamic modulus of the asphalt concrete mixes. The developers of the design guide have developed a laboratory test setup that can provide this parameter. To verify the accuracy and precision of the proposed test setup, several synthetic specimens with known material properties and different length-to-diameter ratios were procured and tested. Since the new design guide advocates the use of specimens with length-to-diameter ratios of less than two, the utility of using end friction reducing layers between the specimen and the end platens were also evaluated. In the end, the hot mix asphalt concrete specimens were also prepared and tested. Overall, the test setup is precise and can be used for dynamic modulus measurement of asphalt concrete mixes. The results also suggest that the specimen geometry and the end friction reducing layers affect the accuracy and precision of estimated dynamic modulus.