RT Dissertation/Thesis
T1 Optimisation of ground penetrating radar testing at traffic speed for structural monitoring of pavements
T2 Optimización de georradar a la velocidad de tráfico para inspección estructural de pavimentos
A1 Marecos, Vânia Margarida da Silva
K1 2505.03 Geografía de Los Recursos Naturales
K1 3308 Ingeniería y Tecnología del Medio Ambiente
K1 3317 Tecnología de Vehículos de Motor
AB Transport infrastructures have a high socio-economic impact on every country.For the last years, the investment priory made for new construction has beenrefocused for maintenance and support activities, which have high demands interms of time, money and personnel. Therefore, optimized pavementmanagement strategies, with reliable and accurate up to date real pavementinformation, are fundamental to enhance maintenance interventions, to reducecosts and to improve safety.Ground Penetrating Radar (GPR) is a non-destructive technique(NDT) that operates at traffic speed and can be used to obtain continuous dataconcerning pavement structure. However, GPR is a method that is used only in afew countries, and mainly for research proposes. This happens due to thecomplexity in the analysis of the results, associated with difficulties in datacollection and signal processing.This thesis identifies the advantages and current limitations of GPR applicationfor pavement monitoring and promotes its use at different stages of thepavement lifecycle and in combination with other NDT methods. The main goalsare to increase the confidence level of the data obtained and to promote a moreefficient data processing.The research starts with a state of the art regarding the application of GPR forroad inspection, not only for thickness measurement but also for the detectionof cracks, voids, delamination and moisture, pathologies typically associated withthe loss of pavement bearing capacity.The following works combine GPR with other NDT techniques first to analyse thecondition of the pavement subgrade during the construction and then to evaluatethe bearing capacity of a rehabilitated pavement. The first study analysesdifferent antenna setups together with two load NDT techniques to detectanomalous areas that can lead to future failure of the pavement, at the subgradelevel. Results from a real scale model show that integration of GPR with load testshelps improve the interpretation. Another study, following the same line ofresearch, presents a combination of GPR with Falling Weight Deflectometer forpavement structural evaluation of a rehabilitated flexible highway. This workfocuses on the sensitivity of the estimated elastic moduli to layers thicknesses. Ithighlights the need for accurate continuous data on layer thickness as input forbearing capacity evaluation and to better support maintenance interventions.Lastly, this thesis proposes a new approach for a coreless GPR calibration method,aiming to provide accurate data on layer thickness measurement. This methodapplies the Common Mid-Point approach to air-coupled antennasmeasurements. It focuses on asphalt layer thickness assessment, as it is the mostrelevant for the structural evaluation of flexible pavements. Results from the GPRtests performed on three real scale physical models, with different flexiblepavement structures, show the improvement of this new methodology, incomparison to existing calibration methods, especially for thinner asphalt layers.As a follow-up, the proposed methodology was implemented for an in situpavement evaluation, as a case study.The main challenges of the implementation of the proposed methodology,conclusions, and future research lines are also presented herein.
YR 2019
FD 2019-01-09
LK http://hdl.handle.net/11093/1116
UL http://hdl.handle.net/11093/1116
LA eng
NO Fundaçao para a Ciência e a Tecnologia | Ref. SFRH/BD/110319/2015
DS Investigo
RD 04-dic-2024