Base Requirements

A variety of subbase types can be used under an RCC pavement structure, but due to the tightness of the transverse cracks in RCC, it is not always necessary to use a stabilized base layer.

A key factor in the performance of a concrete pavement is the potential for erosion to occur, causing a loss of support and a shortened pavement life. Erosion is a function of traffic load, subbase shear strength, and the presence of moisture. Because of the narrow cracks associated with RCC pavement, the subbase/subgrade layer is well protected from moisture infiltration, significantly reducing the potential for moisture to accumulate at the slab/subbase interface. As long as this interface is dry, pumping of eroded material will not take place. The only areas that may be of concern are where longitudinal or transition joints may allow moisture to infiltrate the pavement structure.

As noted above, the joints in the transition areas should be sealed to maintain a closed path to water movement into the joint. For base layers consisting of lower shear strength (i.e., unbound materials), precautions should be taken to seal cold and transition joints. Appropriate measures also should be taken at changes in drainage profile to guard against blowup failure.