Pavement Design Around Utilities – Best Practice

Asphalt concrete pavement surrounding utility structure covers is prone to settlement, cracking, breaking up over time, and potholing, and these distresses are particularly common in wet-freeze climates (e.g., Minnesota). Several factors contribute to their formation, including design requirements, collar material type and cut shape, construction practices, frost heave, and backfill settlement. If not properlymaintained, the distressed pavement can lead to ride quality issues and hazards for vehicles and snowplows. Differences in design details and construction practices can result in different performance; however, differences in pavement performance around utility structure covers are not well documented. The main goal of this Minnesota Local Road Research Board (LRRB) project is to fill this knowledge gap bydocumenting regional agency best practices for adjusting utility covers and patching the surrounding pavement. Information is gathered through a review of existing information, a review of standard details from agencies in and around Minnesota, an agency survey, and follow-up discussions with agencies that are generally satisfied with their practices. No single best practice is identified for design details; however, common themes among agencies include the importance of both inspecting and testing during construction and achieving adequate compaction of all pavement patch layers. This document is developed to assist local transportation agency personnel and engineering consultants in improving design and maintenance of asphalt concrete pavement around utility covers. It highlights successful and unsuccessful regional practices and trends, factors contributing to pavement damage around utility covers, timing of inspections and maintenance, and a framework for evaluating and modifying practice.