NONDESTRUCTIVE TESTING OF TRANSVERSE JOINTS FOR CONCRETE PAVEMENT REHABILITATION

A study was undertaken to develop an inexpensive, easy-to-use nondestructive test procedure for evaluating the structural condition of joints in concrete pavements. The test method consists of a load deflection measurement technique (18,000-lb single-axle load) in conjunction with a finite-element model of the jointed slab system, called JSLAB. Time-deflection measurements were recorded over a variety of concrete pavement thicknesses, ages, and conditions. A series of influence curves was developed to graphically relate slab support (K-value), load transfer, and measured slab deflection. Slab support was determined for new pavements and for old pavements suspected of having voids under the slab. Joint load transfer was determined for dowel bar systems and for a cantilevered load-transfer system. The magnitude of the remaining load transfer was compared with the severity of joint faulting. The process was determined to be very useful as an aid in making decisions to rehabilitate concrete joints. The procedure was successful in characterizing roadbed soil conditioned with lime and then treated with cement as containing greater stiffness than soil (on the same pavement) that was lime conditioned only. Deflection-based guidelines are provided for concrete pavement rehabilitation decisions for joint replacement and for grinding and undersealing of faulted joints.