Optimizing rolling patterns for chip seals using laboratory aggregate loss performance tests on field fabricated samples

This paper presents a study to determine the optimal rolling patterns for chip seals based on aggregate retention performance. Chip seal sections composed of single seals of granite 78M and CRS-2 emulsion are constructed using five different rolling patterns with two or three rollers. Both pneumatic tire and combination rollers are used in developing these patterns. Chip seal samples are obtained from the sections for laboratory testing. The aggregate retention performance is evaluated using the flip-over test, Vialit test, and the third-scale model mobile loading simulator. It is found that the time delay between aggregate spreading and rolling is an important parameter for the aggregate retention performance. The laboratory aggregate retention test results are used along with typical roller speeds and the maximum allowable time delay between aggregate spreading and rolling to develop optimal rolling patterns for two and three rollers.