Poster 19-21

Use of Ground Penetrating Radar Technology to Assess and Monitor Pavement Structural Conditions for Improved Pavement Maintenance and Rehabilitation Strategies

PI: S. Sonny Kim

Co-PI(s): Stephan A. Durham, Jidong J. Yang

Institution(s): University of Georgia

Abstract

Subgrade density is one of the essential components for a structurally sound pavement system. In the field, subgrades soils are compacted to a desirable level to provide a robust platform for pavement layers. Insufficient field compaction is the most frequent construction-related issue resulting in lower subgrade density and potential structural failure. Electromagnetic (EM) density gauges have recently been introduced as an alternative to the nuclear density gauges. These nonnuclear devices use EM signals to measure in-situ density. Such EM density gauges eliminate the need for licenses, training, and specialized storage, as well as the risks associated with devices that use a radioactive source (Romero and Kuhnow, 2002). However, like the traditional methods, the nonnuclear density gauges do not provide continuous test results for the entire pavement area. Determining field subgrade condition in pavement requires a specified number of samples regardless of the density measurement method used. The sample-based assessment is only performed at limited spots and may not represent the entire surveyed road section. Further, a spot test may need traffic control during the test, which may cause traffic congestion. Therefore, a rapid and reliable test method that covers expansive surface areas becomes necessary to enhance the level of confidence in the evaluation. This study proposes a prediction model to estimate in-place subgrade dry density using ground penetrating radar (GPR) shown in Figure 1, which is fast, continuous, and reliable. Besides the subgrade density estimation, the GPR tests provide additional information about pavement structures, such as layers’ thicknesses and layers’ changes.

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