The Great Unsealing: A Perspective on Portland Cement Concrete Joint Sealing

Abstract

The general mission of most transportation agencies is to ensure a customer focus in the development and operation of a safe and efficient transportation system. The customers desire comfort, convenience, safety, and cost-effectiveness in a transportation system. Agency research must have the objectives of addressing customer-related issues and measuring benefits of importance to them. Accordingly, any joint and sealant research must answer the questions, Why do we seal? and Is it cost-effective? Joint and sealant studies of portland cement concrete (PCC) pavements must address whether joint sealing enhances total pavement performance and is cost-effective, and, if so, what sealant system should be used. The Wisconsin Department of Transportation (WisDOT) has been studying the effect of PCC joint/crack sealing on total pavement performance for 50 years. By 1967 there was substantial documentation that filling and refilling of contraction joints had no beneficial effect on pavement performance. By 1984, it was concluded that pavements with unsealed joints had better overall performance (distress, ride, materials integrity) than pavements with sealed joints. In 1990, WisDOT passed a policy eliminating all PCC joint sealing, in new construction and maintenance. This "no-seal" policy has saved Wisconsin $6,000,000 annually with no loss in pavement performance and with increased customer safety and convenience. The entire PCC sealing issue is beginning to be addressed at the national level, ensuring no false assumptions and with the customer’s needs in view.