In Phase I, the research team contacted each of 16 participating states to gather information about concrete and concrete material tests. A preliminary suite of tests to ensure long-term pavement performance was developed. The tests were selected to provide useful and easy-to-interpret results that can be performed reasonably and routinely in terms of time, expertise, training, and cost. The tests examine concrete pavement properties in five focal areas critical to the long life and durability of concrete pavements: (1) workability, (2) strength development, (3) air system, (4) permeability, and (5) shrinkage. The tests were relevant at three stages in the concrete paving process: mix design, preconstruction verification, and construction quality control. In Phase II, the research team conducted field testing in each participating state to evaluate the preliminary suite of tests and demonstrate the testing technologies and procedures using local materials.

This research project investigated important variables that impact the homogeneity and rheology of concrete mixtures. The project consisted of a field study and a laboratory study. The field study collected information from six different projects in Iowa. The information that was collected during the field study documented cementitious material properties, plastic concrete properties, and hardened concrete properties. The laboratory study was used to develop baseline mixture variability information for the field study. It also investigated plastic concrete properties using various new devices to evaluate rheology and mixing efficiency. In addition, the lab study evaluated a strategy for the optimization of mortar and concrete mixtures containing supplementary cementitious materials.

Experimental composite pavements were constructed at MnROAD in Minnesota and the University of California Pavement Research Center at Davis, where the pavements were instrumented and monitored under climate and heavy traffic loadings. A composite pavement consisting of HMA over jointed plain concrete also was constructed in the field by the Illinois Tollway north of Chicago. At the Tollway, extensive field surveys were performed on 64 sections of the two types of composite pavements. This project also evaluated, improved, and further validated applicable structural, climatic, material, and performance prediction models, and design algorithms that are included in the AASHTO MEPDG and DARWin-ME, CalME, NCHRP 1-41 reflection cracking, NCHRP 9-30A rutting, and the Lattice bonding model. The current DARWin-ME overlay design procedure for HMA/PCC and a special R21 version of the Mechanistic-Empirical Pavement Design Guide (MEPDG [v.