Evaluation of high-early strength PCC mixtures used in full depth repairs

The research described herein was conducted as a part of NCHRP Project 18-04B, Early Opening-to-Traffic Portland Cement Concrete for Pavement Rehabilitation [Van Dam TJ. Durability of ‘Early-Opening-to-Traffic’ portland cement concrete for pavement rehabilitation. Final Report, NCHRP Web Document 76, Transportation Research Board, National Research Council, Washington, DC; 2005.]. In the study fourteen different high-early strength portland cement concrete (PCC) full-depth repair mixtures (two replicates or batches were prepared for each mixture for a total of 28 batches) were designed for a 6–8 h opening to traffic window. The fresh and hardened concrete properties, freeze-thaw durability and microstructural properties of the concrete were assessed as part of the laboratory testing program. As a result of this assessment it was determined that high-early strength PCC mixtures of adequate strength could be produced, but that interactions between the various constituents could result in durability problems in some mixtures, particularly those made with Type III cement and high-range water reducers. It is recommended that durability-related testing be conducted on such mixtures to ensure longevity of the repair.