Precision of modal analysis to characterise the complex modulus of asphalt concrete

Modal analysis is an economic and efficient test method to characterise the complex modulus of asphalt concrete. In this paper, the precision of modal analysis was evaluated by performing testing at several laboratories on two cylindrical asphalt concrete specimens. In addition, the complex moduli characterised by modal analysis were compared to cyclic tension-compression testing. The results showed that the coefficient of variation was less than 3% at loading frequencies above 10 Hz for the complex modulus determined through modal analysis. The comparison of the complex modulus determined from modal analysis and tension-compression testing resulted in a coefficient of variation values not more than 9% for loading frequencies ranging from 0.1 to 109 Hz.