The Mapping of Road Pavement Structure around the Seismically Active Regions by Using Ground Penetrating Radar

The Banda Aceh-Sigli Road has become the central infrastructure in connecting the capital city of Aceh province with other districts. In some places, the road construction was in rice fields dominated by high sedimentation areas. The Aceh also has the Great Sumatran Fault, which has caused many earthquakes and damaged public infrastructure, including roads. The density of the soil structure as an infrastructure buffer needs to be observed before road damage can endanger the community. This study aimed to apply Ground Penetrating Radar (GPR) as a non-destructive method that detects subsurface conditions based on permittivity parameters. The method is measured using the IDS Georadar Opera Duo instrument, which operates with a frequency of 250 MHz and 750 MHz for a penetration depth of 4 m, which is measured on eight intersecting tracks, where two profiles have a length of 110 m measured in the direction of the road segment and five tracks with a length of 11 m is measured by a cross. GresWin2 software is used for optimal analysis and modeling of 2D radargram. The radargram model describes a subsurface structure consisting of three layers, where the first layer with a depth of 0 – 0.25 m is asphalt, and the second and d layer with a depth of 0.25 – 0.75 m was identified as the base course layer. In comparison, the third layer is interpreted as a sub base course layer at a depth of 0.75 - 4 m below. The analysis results also show a linearly damaged road structure with high propagation speed and large wave amplitude. Therefore, based on data processing, it can be concluded that the application of GPR is a non-destructive, fast, and economical method for evaluating road structures.