Rutting prediction of a granular material for base layers of low-traffic roads

This paper analyses the permanent deformation performance of an unbound granular material for base layers of low-traffic roads. The material has been subjected to repeated triaxial loads. The shakedown theory was used to classify the structural response of the unbound granular material to the applications of load cycles. Three models were fitted to express the cumulative permanent strain as a function of the number of load cycles. In general, the predictions of two models previously studied by other researchers proved to be good but in the long-term, they tended to underestimate the measured values. In contrast, a third new model – the sum of two well known models – offered excellent predictions, which in the long-term did not tend to either underestimate or overestimate the measured values.