Benefits of GPR
- Produces a continuous pavement thickness profile
- Reduces the number of cores and testing time
- Reduces Road Damage
- Increases Field Safety
- Reduces Analysis Time
Limitations of GPR
- Sensitive to Ground Water
- Limited Depth
- May not detect thickness of concrete or base layer if there is insufficient contrast
GPR Reports
Implementation of Ground Penetrating Radar (PDF 32 MB 29 pp)
GPR Summary (PDF 1 MB 5 pp)
GPR Video (MPG 117 MB)
For more information:
Shongtao Dai, Road Research
Matt Lebens, Road Research
Research Topics
Resources
- Pavement Interactive
- MnPave
- Seal Coat Design
- Test Section Tracking
- Seasonal Load Limits
- Construction Tools
- Mn/DOT Library
- Research Services
Organizations
- Local Road Research Board
- Transportation Engineering and Road Research Alliance
- Long Term Pavement Performance
- Transportation Research Board
- Center for Transportation Studies
- Center for Transportation Research and Education
- Shingle Recycling
Ground-penetrating radar (GPR) is fast becoming a viable technology worldwide for surveying subsurface features and defects in flexible and rigid pavements. GPR has the potential to be used for a variety of pavement applications, including measuring the thickness of asphalt pavement, base and sub-grade; assisting in the analysis of rutting mechanisms and locating subsurface objects.
GPR operates by transmitting short pulses of electromagnetic energy into the ground. The reflected images of these pulses are analyzed using one-dimensional electromagnetic wave propagation theory. These pulses are reflected back to the antenna with amplitudes and arrival times that are related to the dielectric constants of the material layers.
Potential Applications of GPR
- Determine Pavement Layer Thickness
- Estimate Material Properties
- Identify Stripping Zones within Asphalt
- Detect Subsurface Voids
- Analyze Rutting Mechanisms
- Detect Subsurface Anomalies
- Rebar and Dowel Bar Locates
Pavement Thickness Determination
Determination of pavement layer thickness is one of the more successful applications of GPR. For data collection at normal highway speeds, an air coupled antenna is attached to a vehicle, with a penetration depth of approximately 30 in. Experience has shown that GPR works well on flexible pavements (asphalt) where there is a strong dielectric contrast between layers, but may be less effective on rigid pavements (concrete) where the presence of moisture tends to attenuate the radar signal, or where the contrast between layers is minimal such as between concrete and granular base materials.