Using Ground-Penetrating Radar to Detect Indicators of Premature Joint Deterioration in Concrete Pavements

Many Midwestern states have observed premature joint deterioration occurring in jointed plain concrete pavements. This deterioration can be attributed in part to fluid collecting in the joint resulting in either accelerated freeze-thaw damage or deleterious chemical reactions that spall and crack the concrete. It has been proposed that if fluid collection in joints can be detected early enough it may enable lower cost corrective actions to be taken that extend the life of the pavement, such as repairing the joint sealant or applying concrete sealant to the face of the cracks, before the joint deteriorates and spalls resulting in the need for higher cost partial depth pavement repairs. This paper examined the potential use of ground penetrating radar (GPR) as one technique to rapidly and nondestructively assess whether fluid may be accumulating in the saw-cut joint behind the joint sealant. An experimental campaign was performed using a large number of slabs with differing fluid concentrations. It is recognized that the typical GPR response (wiggle trace or scan) is complex and may be hard to interpret accurately, especially in the field. To overcome this challenge the researchers propose the use of complexity-invariance distance (CID) signal processing to obtain a single number that reflects the potential for fluid in the joint. It is proposed that the CID can be used with other simple features of the wave (e.g., the derivate) to estimate which joints may contain fluid thereby providing insights into which joint sealant sections may need to be repaired or which joints may require a larger maintenance effort.