Laboratory and In Situ Investigation of Chip Seal Surface Condition Improvement

Abstract

This study focuses on determining the effect of different types of binder and aggregate on chip seal performance in both laboratory and in situ settings. Eight different chip seal test sections were constructed on existing asphalt concrete as the pavement preservation technique of choice. Two different binders, CRS-2L modified emulsion and B100/150 penetration hot asphalt cement, were used in the test sections. Also, two types of aggregate, limestone, and basalt, were used. The sand-patch test as well as visual evaluations was conducted on the test sections regularly. In addition to physical and chemical characteristics, the adhesion resistance of the utilized materials was determined in the laboratory and compared with the test section results. The loss of aggregate (also called raveling or shelling), bleeding deteriorations on each test section were evaluated over time in respect to binder and aggregate type. The results indicate that after chip seal construction, the macrotexture of the existing asphalt concrete increased significantly. It was also determined that CRS-2L chip seal showed better performance than B100/150 penetration hot asphalt cement. With regard to the type of aggregate used for the chip seal, limestone showed better raveling performance when compared with basalt. In addition, in the test sections, the right and left lanes demonstrated different levels of severity distress because of varying traffic distributions. It was also seen that macrotexture is one of the best parameters to determine chip seal performance and to follow its progress over time. (C) 2014 American Society of Civil Engineers.