National Concrete Pavement Technology Center

Project description

An experimental research study was conducted to develop optimized concrete mixtures for jointed plain concrete (JPC) pavements and field evaluation of newly constructed JPC pavement sections along South Dakota highways. Using South Dakota aggregates, different concrete mixtures were assessed for optimum workability, durability, and cost. The optimized mixtures incorporated 1.5" aggregate top size and reduced cement content. Mixtures containing pea rock exhibited poor freeze-thaw durability. Mixtures with 1.0" aggregate top size and 65/35 coarse-to-fine aggregate ratio exhibited low workability. A new laboratory technique that involves measuring the “specific work” of fresh concrete was developed to compare workability of different mixtures. Field data obtained from newly constructed JPC pavements demonstrated the following: thicker concrete pavement results in greater change in joint gap width, while the presence of asphalt underlayment results in lesser change in joint gap width, unsealed transverse joints allow for significantly higher moisture ingress than silicone sealed or hot-pour sealed joints, silicone sealed joints exhibited the least moisture ingress, treating the freshly placed JPC pavement with 1.5 times the normal amount of curing compound had a significant effect on maintaining pavement smoothness with time, high initial load transfer efficiency was achieved at joints with reduced dowel bar arrangements, and joint faulting was negligible across joints with either standard dowel bar configuration or reduced dowel bar configuration.