Geophysical Characterisation of Road Subsurface

Road makes a very huge contribution for the development of economic and also to the social benefits. Poorly maintenance of the roads may reduce the efficiency of the business and trading. There are few non-destructive methods have been introduced and developed to measure the strength and deformation properties of layer that made up the pavement structure. The properties are either used to design new pavement structures or to diagnose the causes of existing problem so that appropriate rehabilitation strategies can be chosen. This study is about determining the ground profile of defect and non-defect pavement using electrical resistivity method. The purpose of this study is to investigate subsurface condition under the defect and non-defect of road pavement using electrical resistivity on actual field. Since the testing was conducted on pavement, the actual electrodes of one and half (1.5) foot steel were changed to 4 inches nails. The resistivity was measured by injecting current to the ground through electrodes and the resultant voltage difference was measured at two potential electrodes. In this study, 3 locations with different damages were selected and the resistivity value of defect and non-defect pavement were measured and profiled. Three types of defects which are crocodile cracking at the parking bay for busses, rutting and potholes at access road and transverse cracking located at car park area were investigated. The finding of this study shows that the value of electrical resistivity varies from one defect to another. This is because of influence of few factors during the early construction and the types of defect on the pavement. The advantage of using electrical resistivity method in determining the defect and non-defect pavement is its one of the non-destructive method that can be applied without making and leave major damage to the pavement surface.