Prediction of flow rutting in asphalt concrete layers

This paper evaluates an approach for predicting rut formation in asphalt concrete (AC) layers. The approach is based on a linear viscoelastic model for predicting permanent vertical strain in AC layers subjected to a moving load. The input data are tyre pressure, loading speed, lateral wandering of loading wheel, shear modulus and phase angle of AC layer. The analytical approach takes into consideration the change in material characteristics in respect of temperature and changes in the air void content of AC layers due to repeated loading. The approach is verified by a full-scale accelerated loading test at different temperatures. The approach has shown good agreement as regards the prediction of flow rutting in AC layers. In addition, the approach is capable of calculating rutting profiles including the upheaval, which is important for estimating rut depth.