Nondestructive Testing

Our rapid nondestructive testing (NDT) is the best and most economical means of evaluating concrete in significant detail over large areas.

We employ several testing techniques to achieve our results. Sonic/Ultrasonic has proven to be the most effective method for the assessment of concrete. Sonic/ultrasonic testing determines moduli values (Young's, shear, bulk, and Poisson Ratio) and predicts unconfined compressive strength and thickness. This information allows us to determine the presence of micro and macro cracking (and it's depth of influence), in addition to delamination, and voiding. Most importantly, this method will detect and document abnormalities, well before concrete repairs are necessary, and is very effective in providing comprehensive evaluations of bridges, piers, parking garages, tanks, tunnels, pipes, piles, drilled shafts, and caissons.

Electrical methods (radar, conductivity, and electrical resistivity) depend greatly on the moisture content of the material being tested. Moisture laden cracks and voids which contrast with the surrounding material's electrical properties will be identified. Radar is used to locate reinforcing and determine bar spacing and depth of cover.

Geophysical Testing

NDT Corporation has extensive experience using all geophysical techniques but particular emphasis is placed on those techniques that provide high resolution and accuracy for engineering studies. Our emphasis is placed on those techniques that measure engineering properties, at high resolution, such as seismic refraction which may be augmented by ground penetrating radar. The seismic refraction method provides soil/bedrock profiles, general material identification (see chart below) and directly measures the modulus values or deformation characteristics of the material. The radar method is highly sensitive to moisture content and changes in electrical characteristics (conductivity, dielectric constant). Since the electrical characteristic changes are many times associated with changes in bedding, the presence of sinkholes, soils failures etc, can provide significant information. Our experience include applications such as trench-less installation of wire and pipes, detailed foundation studies for tunnels, buildings, bridges road cuts and investigation of existing structures with unknown foundation conditions.