Guidelines for Prime Coat Usage on Low-Volume Roads

Abstract

Prime coat has a purpose in the pavement construction process, yet many times prime is misused or eliminated during the project. Although most of the time no harm appears to occur to the roadway, and thus this practice may be viewed as acceptable, technical guidance is warranted to ensure appropriate usage. The objective of this study was to produce a prime coat guide for Central Federal Lands Highway Division project development and field personnel to provide decision-making guidance. The study consisted of a literature search, which focused on handbooks and technical reports, and a review of agency construction specifications. A phone survey of state departments of transportation in the region was undertaken to provide information on current practice. Finally, a review of both the potential harmful and the positive environmental effects of the prime coat process, including the various bituminous products used, was undertaken. On the basis of the information collected, a guideline for project development and field personnel was developed. The guideline provides guidance on how to use, when to keep, and when to eliminate prime coats.