Analysis of Field Monitoring Data of CRC Pavements Constructed with Grade 70 Steel (7-4925-1)

This report addresses important factors associated with the design of steel reinforcement in terms of layer configuration, bond characteristic, climatic affect, and others relative to an assessment of the suitability of the CROP 8 program to represent and predict steel stresses in CRC pavement systems. It was necessary to instrument an actual section of CRC pavement for concrete and steel strains as they fluctuated under climatic and seasonal changes. The steel rebars were instrumented in a manner that would limit disturbance of the bond between the steel and the concrete, yet allow for precise measurements of the steel strain at various distances from the crack face. Other field sections containing Grade 70 steel were also included in this study. Crack spacing and crack width data were collected and reported.|In light of this emphasis, the researchers recognized that a key aspect of the steel design considerations is how important parameters-such as the steel surface area, degree of bond, the grade of steel, and the amount of steel-relate to the maximum opening transverse cracks in the pavement may attain over the design life of the pavement. Inherent in configuring the reinforcement in CRC pavement to perform at a adequate level below its yield limit is the maintenance of the transverse crack widths below specified levels to insure adequate stiffness at the transverse cracks. Crack width data varied as a function of the distance from the pavement surface, and it was noted in the report that the vertical position of the steel within the slab affects this variation and consequently should be a consideration in determining the vertical position of the reinforcing layer in construction.