Using a shakedown approach as a simple means of predicting rutting in unsealed and chip-sealed pavements.

Several laboratory test results are presented and the shakedown interpretative framework is applied to them in order to show its application and limitations. These results show that there are some differences between granular materials and the original model. These must be taken into account before the shakedown model can be satisfactorily used to replicate the behaviour of granular material under repeated loading. With this proviso, it is shown that the modified shakedown model can be used to predict whether aggregate will undergo stabilising, slow continual or rapid plastic straining under the application of traffic loading. Thus the technique can be used to predict whether or not the aggregate will undergo acceptable or unacceptable shear movement and hence to predict whether the pavement will suffer from excessive rutting. It is concluded that the technique has value as a predictive tool to ascertain whether or not rutting will be of concern to the road owner but that the magnitude of rutting which may arise cannot be predicted with great accuracy at present. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E208431.