Abstract
The bearing capacity of sub-asphalt soils, which is a critical parameter for assessing pavement conditions and guiding pavement maintenance, is greatly influenced by soil water content. In this study, ground-coupled ground penetrating radar (GPR) techniques were used to non-destructively monitor the volumetric water content in sub-asphalt aggregate layers during an extended infiltration experiment. Water was injected over a period of several months into two differently layered pavement test sections, one of which contained a sub-asphalt drainage layer. GPR travel time data were used to estimate the water content in each aggregate layer and the variations in water content with time, and GPR amplitude data were used to indicate areas of high water content immediately beneath the asphalt layer. The GPR data revealed significant variations in the water content of the aggregate layers in both the horizontal and vertical directions and over time. Comparison of the water content estimates from GPR travel time data and from gravimetric water content measurements showed that the difference between the two techniques was approximately 0.02 cm3/cm3. These results suggest that GPR techniques can be used for accurate, non-invasive water content estimation in sub-asphalt aggregate layers and for assessing the efficacy of pavement drainage layers.
Original language | English |
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Pages (from-to) | 129-153 |
Number of pages | 25 |
Journal | Journal of Applied Geophysics |
Volume | 57 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2005 |
Externally published | Yes |
Funding
This study was funded by Caltrans through the Partnered Pavement Research Center and NSF EAR-0087802 to Prof. Yoram Rubin and Prof. John Harvey. We sincerely thank Prof. Michael Riemer (Dept. of Civil and Env. Eng., Univ. of California, Berkeley) for his unfailing support and advice throughout the experiment, Dr. Michael Herkelrath (USGS, Menlo Park) for providing the laboratory data to create petrophysical relationships, and Ed Diaz and staff (Richmond Field Station, Univ. of California, Berkeley) for their assistance with data collection. We also wish to thank Dr. A. Hördt, Dr. Neil Anderson and Dr. Timo Saarenketo for their insightful reviews of this manuscript; we feel that their suggestions have significantly improved the presentation of this research. The GPR processing was carried out at the Center for Computational Seismology (CCS) at Lawrence Berkeley National Laboratory.
Keywords
- Ground penetrating radar
- Pavement aggregates
- Reflection
- Water content