Modified Cross model for predicting long-term creep behavior of sand asphalt

• Cross model and TTSP are combined to predict long-term creep behavior of sand asphalt.
• Cross model is modified by a correction factor for more accurate long-term prediction.
• Short-term creep tests and constant strain-rate tests are conducted for model calibration.
• Long-term creep tests lasting more than 28 days are conducted for model validation.
• The modified Cross model can give a better prediction than Cross model and TTSP.

The Cross model is modified by introducing a long-term correction factor to predict the long-term mechanical behavior of compressed sand asphalt with the combination of the time–temperature superposition principle. A series of short-term experiments, including one-hour creep tests and constant strain-rate tests, are carried out to determine the Cross model parameters. Two long-term creep tests lasting more than 28 days are conducted at two different stress levels. One is for determining the long-term correction factor and the other for the model validation. It is found that the modified Cross model can predict the long-term viscoelastic behavior of sand asphalt better than the Cross model.