Introduction

This manual was developed for use in designing and constructing chip seals over hot mix asphalt pavements. It documents best practices based on the findings of research during NCHRP Project 14-17, Manual for Emulsion- Based Chip Seals for Pavement Preservation. In addition, certain subjective or qualitative judgments previously needed during chip seal construction have been eliminated in favor of field and laboratory testing. These include the moisture content of the seal before traffic can be released, judging surface condition so emulsion application rate can be adjusted for surface demand, and measuring the emulsion consistency in the field. The introduction of these new techniques should improve the probability of success when designing and constructing chip seals, but they do not replace the significant judgment required. Also, the success of any chip seal depends on conformance to best practices, and variance or elimination of these practices often leads to disappointing performance.