<p>Road pavements are subject to a range of problems due to traffic and temperature variations&#160;</p><p>producing cracks that propagate to the pavement surface. Cracks need to be assessed to avoid&#160;</p><p>deterioration and provide confidence in the functioning of the road system. Cracks are usually&#160;</p><p>maintained after visual inspection by filling with bitumen as a first rehabilitation technique to&#160;</p><p>avoid further deterioration and absorbing water leakages. Although this temporary solution does&#160;</p><p>not extend the pavement life cycle it can help to avoid additional problems occurring within the</p><p>pavement. This work is proposed to aid the development of understanding and characterization</p><p>of cracks filled with bitumen in both rigid and asphalt pavements.</p><p>This study reports on the results of several laboratory experiments that were performed to&#160;</p><p>explore the capability of Ground Penetrating Radar (GPR) in the assesment of bitumen-filled&#160;</p><p>cracks in both rigid and asphalt pavements, respectively. These tests were focused on the&#160;</p><p>analysis of cracking filled with bitumen using a GPR system equipped with a ground-coupled&#160;</p><p>antenna with a 2.3 GHz central frequency, and varying the antenna orientation with respect to the&#160;</p><p>crack axis.</p><p>Results showed the variation in characterization and changes in amplitude that could be expected&#160;</p><p>when analysing bitumen-filled cracks in concrete and asphalt specimens, dependent upon the&#160;</p><p>antenna orientation being used; GPR B-scans were compared to images from computational&#160;</p><p>models using a Finite-Difference Time-Domain (FDTD) method-based software package&#160;</p><p>(gprMax2D). Additionally, a field survey carried out provided images consistent with the</p><p>comparable conditions of the lab tests. The results of this work proved the capability of the GPR</p><p>method to detect and characterize cracks filled with bitumen in pavements across a range of&#160;</p><p>crack dimensions and pavement types.</p><p>&#160;</p><p>Keywords</p><p>GPR, NDT, Rigid pavements, Asphalt Pavements, Cracks, Computational models, Target orientation,</p><p>Pavement assessmen</p>
Generation of picosecond pulses directly from a 100 W, burst-mode, doping-managed Yb-doped fiber amplifier