Historically MDOT used to have large stone concrete mixtures which performed well (Woodward Avenue, I-69 near Marshall and Davison Freeway), except when susceptible to D-cracking. A large and more durable aggregate would assist in maintaining pavement integrity at crack locations by providing adequate vertical shear resistance from the "ball and socket" mechanism of the large stone protruding across the crack face. The use of large stone concrete mixes may reduce the mortar content and subsequently reduce shrinkage stresses, and therefore reduce the potential of early age cracking in pavements. This is very important for pavements and bridge decks where geometric constraints induce non-uniform levels of internal stress characteristics into the concrete. The levels of stress and strain can be reduced by the proper selection and proportioning of materials to maintain an extended pavement service life. Furthermore, the reduction in the amount of cement content may result in an overall material cost reduction.

The project objectives are: (1) Monitor both short and long term mechanical properties of large stone concrete mixtures placed at the I-75 project from the Ohio border to 12 miles north (both north and south bound lanes) and (2) Monitor both short and long term durability properties of these mixtures for the same above mentioned locations