Quantification of Uncertainty in the Master Curves of Viscoelastic Properties of Asphalt Concrete

The prediction of asphalt concrete (AC) behavior using a continuum damage mechanics approach requires viscoelastic properties like creep compliance (CC) and relaxation modulus (RM) values. Because of practical limitations, dynamic modulus (DM) and phase angle (PA) measurements are used to construct CC and RM master curves. Numerous approximate interconversion techniques have been used for this purpose. Because of issues during testing, fabrication processes, and interconversion approximations, significant scatter can be found in CC- and RM-constructed master curves. The present study proposes and compares quantification methods to address scatter found in CC and RM master curves. The scatter found in CC and RM master curves at different reduced time values is quantified using uncertainty quantification (UQ) techniques. For this purpose, several AC specimens with identical volumetric properties were prepared and tested for DM and PA values. Furthermore, CC and RM master curves were obtained using DM and PA through approximate interconversion techniques. Finally, CC and RM values obtained (at a fixed time using particular simulation techniques) with all specimens were combined. Using these values, scatter in CC and RM values (at a specific reduced time) was evaluated using UQ techniques. The results indicate that the choice of simulation technique affects the statistical parameters associated with probability density function (PDF) to a large extent. This, in turn, significantly affects the shape of the PDF at a chosen reduced time of interest. In other words, uncertainty found in CC and RM values are dependent on the choice of interconversion technique and time of interest.