Transient response of a vibratory roller during compaction

Compaction is the last, but possibly the most important, phase that an asphalt pavement goes through during construction. Adequate compaction is necessary for the long term performance of an asphalt pavement. Inadequate/improper compaction is one of the leading causes of early deterioration and failure of these pavements. Current quality control procedures also depend on destructive testing to ascertain the quality and thereby contribute to the early failure of the pavements. Non-destructive Intelligent Compaction (IC) techniques have been introduced to control the quality of construction of these pavements, but with limited success. Currently available IC systems display real-time measurements that are indicative of the pavement quality. However, these measurements are not adequately correlated with any measurements obtained from the finished pavement. One of the reasons for the poor accuracy is the lack of adequate modeling and mathematical analysis in the design of IC systems. These systems are typically built using heuristic data and are not amenable to mathematical analysis. In this paper, the dynamics of the vibratory compactor is studied and the effect of system parameters like the thickness of the pavement, type of asphalt mix, etc., on the response characteristics is determined. These measurements are then used to analyze the transient response of a vibratory roller during compaction. The response characteristics provide an insight into the requirements for feedback control and can be used as a starting point for improving the performance of IC systems.