Application of the ground penetration radar and electric imaging in detecting the voids under the concrete pavement | |
| Author | Wattana Maneechot |
| Call Number | AIT Thesis no.GE-06-05 |
| Subject(s) | Ground penetrating radar Pavements, Concrete Imaging systems in geophysics |
| Note | A thesis submitted in paitial fulfillment of the requirements for the degree of Master of Engineering in Geotechnical and Geoenvironmental Engineering (with Specialization in Geosystem Exploration and Petroleum Geoengineering), School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-06-05 |
| Abstract | The void beneath the concrete pavement have caused in the past concrete pavement subsidence, collapse, and thereby are likely prone to more widespread subpavement erosion and void development. Many roadways and highways in Thailand have suffered from failures and cracking due to the void underneath. Thus, early detection of voids is an important task. This study applies the near surface geophysical techniques, i.e., Ground Penetration Radar (GPR) and Electric Imaging (EI) for detection of the void beneath the concrete pavement. The main works in the study include: i) construction of a concrete pavement model; ii) laboratory testing; iii) GPR and El surveys over the concrete pavement model and at a real site on the Paholyothin road. A site on the AIT campus was selected for construction of a concrete pavement model, which is 3.5 m wide, 10 m long, and 0.25 high. Beneath the concrete layer, three types of voids were constructed. The voids are filled by styrofoam. To make sure of construction quality, a number of geotechnical tests were done for the construction materials, including sieve analysis, Atterberg limits, compaction test, CBR test and sand cone test. All the test results shoved that the construction material meet to design criteria. A total number of 30 concrete samples were casted into the molds of 4-in diameter and 8-in height. GPR and resistivity tests were done on these samples in both laboratory and outdoor conditions to see how the concrete properties (dielectric constant and electric resistivity) change with time. Geophysical forward analyses were performed to investigate the effectiveness of these methods before stating the field surveys. It was found that for GPR the antenna of 900 MHz is the most suitable, while for El we need to use small electrode spacing with Wenner array. The GPR testing over constructed concrete pavement model was performed using GSSI SIR-2® system with two antennas of 1.5 GHz and 900 MHz. The test results by the 1.5 GHz antenna did not show clearly the void location, but the result tested by the 900 MHz antenna could detect the voids quite well. The rehars in the concrete layer are well mapped by both frequencies. The El survey was carried out with small unit spacing of 0.10 m, 0.25 m, 0.50 m, respectively. The El results over the concrete pavement model could indicate well the void location and steel bar, especially the survey with unit spacing of 0.50 m. GPR and El surveys were also conducted at a site in front of AIT on the Paholyothin road. The GRR survey with 1.5 GHz and 900 MHz antennas could show clearly discontinuities at the joints of road slabs. The El results also detected the highresistivity zone under the joints, that might be related to voids underneath. Through successful results, it is hoped that study could provide a good introduction of Ground Penetration Radar (GPR) and Electric Imaging (EI) techniques that can be used in various applications in geotechnical engineering, especially for detection of voids under the concrete pavements in Thailand. It is also recommended more studies be done on using GPR and El for highway investigation |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-06-05 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Giao, Pham Huy; |
| Examination Committee(s) | Noppadol Phien-wej;Bergado, Dennes T; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2006 |