The project identified several factors that influence the performance of early-opening-to-traffic concrete and potential concrete material combinations and presented a plan for further evaluating these material combination and formulating guidelines for the selection of appropriate materials, mixtures, and construction practices for different applications.

With increasing traffic in urban areas, motorists are becoming less tolerant of delays during pavement rehabilitation. To minimize delays, state highway agencies use "early-opening-to-traffic" rehabilitation strategies that allow work to be completed at night or during periods of low traffic. Generally, portland cement concrete used in these applications is expected to become strong enough to carry traffic within 6 to 24 hours after placement. Rigorous requirements for mix design and strength development have always been stipulated for early-opening-to-traffic concrete applications, often with limited consideration given to construction aspects that influence the long-term performance and durability. Much of the recent research on early-opening-to-traffic concrete investigated the mechanical properties, but not the durability aspects. In the absence of this information, the durability of the concrete used in these applications cannot be accurately predicted, the long-term performance of the rehabilitated pavement cannot be assured, and the cost-effectiveness of the rehabilitation strategy cannot be adequately assessed. Thus research is needed to address the durability issues associated with the use of portland cement concrete for early-opening-to-traffic pavement rehabilitation and to develop guidelines for the selection of suitable materials, mixtures, and construction practices for different applications. This project provided the first step in the process for achieving this objective. Further research will be performed under NCHRP Project 18-4B.

Research included a review of relevant literature, an analysis of current practices relevant to the use of early-opening-to-traffic concrete, and an evaluation of potential concrete material combinations.