Radar (GPR)

The Ground Penetrating Radar (GPR) method is primarily used on structures to locate and measure the depth of embedded objects in concrete such as conduits, rebar, and post-tensioning (PT) cables. Embedded or buried objects will be detected by this method if the objects have different electrical properties than their surrounding material, which could be soil, rock, or concrete. The method can also be used to map the thickness of slabs along a scan line, and for location of some types of flaws (such as voids) in concrete.

When the method is applied in a regular grid of scan lines, the data collected can be processed to produce a 3D image of the embedments within a slab or wall. This can be used to allow visualization of the entire rebar mat at once, to track PT cable drape, and to locate features with unusual geometeries within the slab or wall.NOTE: SASW measurements are accurate to within 5% for the determination of the thickness and stiffness of the top layer in a pavement system.