DEVELOP DRAFT CHIP SEAL COVER AGGREGATE SPECIFICATION BASED ON AGGREGATE IMAGING SYSTEM (AIMS) ANGULARITY, SHAPE, AND TEXTURE TEST RESULTS

Abstract

The objective of the study is to improve Oklahoma Department of Transportation (ODOT) chip seal design and performance through introducing new criteria for the selection of cover aggregate and binder. The study evaluates the shape and texture-related index properties, as well as durability, of commonly used cover aggregates in chip seal programs in Oklahoma. Additionally, it provides a methodology for inclusion of these characteristics as a metric in future chip seal specifications. The study includes both laboratory testing and construction and performance evaluation of chip seal test sections. The study quantifies how well the newly developed performance-based uniformity coefficient (PUC) correlates with chip seal performance in Oklahoma, and if it should be incorporated into state chip seal specifications. It has generated aggregate-binder compatibility data, based on the surface free energy (compatibility ratio) approach, for commonly used aggregates and asphalt emulsion binders in Oklahoma. Moreover, the chip seal construction practice followed by different ODOT Maintenance Divisions was documented and the best practice identified. This repository of information will be a useful resource for ODOT maintenance divisions.