| Title |
CONCRETE COVER DETERMINATION USING GROUND PENETRATING RADAR (GPR)
|
| Accession No |
00769472 |
| Authors |
Roberts, G E; Amrol, J J |
Corp. Authors
/ Publisher |
New Hampshire Department of Transportation  ; Federal Highway Administration
|
| Publication Date |
19990800 |
| Description |
15 p.;
Appendices(1); Figures(3); Photos(2); Tables(3) |
| Languages |
English
|
| Abstract |
Since 1992, the New Hampshire Department of Transportation (NHDOT) has utilized a quality control/quality assurance (QC/QA) specification for construction of new reinforced concrete bridge decks. Under this specification, the Contractor's payment is based on certain measured attributes, including the depth to reinforcing steel (concrete cover). Originally, the NHDOT utilized a limited-production device known as a rolling pachometer to measure the concrete cover. When this instrument was no longer serviceable, a need arose to find a suitable replacement device. Ground penetrating radar (GPR) was identified as a potential measuring device for concrete cover. The NHDOT partnered with Geophysical Survey Systems, Inc. of Salem, New Hampshire to develop a ground-coupled radar device for this use. To evaluate the effectiveness, accuracy and precision of the unit, the NHDOT collected GPR data from 53 locations at 12 sites and compared it to actual measurements obtained by drilling into the decks. After technicians gained experience using the device, all GPR predictions were accurate to within 3 mm of actual measured depths. The mean deviation between predicted and measured values was 1.95 mm for the study. The GPR data correlated with the actual measured depths with a correlation coefficient of 0.98 and a standard error of estimate of 2.2 mm. Multiple runs with the GPR device produced a maximum standard deviation of 2.15 mm. The NHDOT believes that these data support the use of GPR for measuring concrete cover, and has implemented the technology through its QC/QA specification for concrete bridge decks. |
| TRT Terms |
Accuracy ; Bridge decks ; Concrete ; Construction ; Correlation analysis ; Ground penetrating radar ; Measurement ; Payment ; Precision ; Quality assurance ; Quality control ; Specifications ; Standard deviation ; Thickness |
| Geographical Terms |
New Hampshire |
| Other Terms |
Cover depth |
| Subject Areas |
H33 CONSTRUCTION; I53 Construction of Bridges and Retaining Walls |
| Contract Number |
DTFH71-97-PTP-NH-12 |
| Report Number |
PTP NH1997-01,; Final Report |
| Availability |
National Technical Information Service |
| URLs |
|
| TRIS Files |
HRIS |
| Database |
TRIS Online |
TRT
