Underwater Nondestructive Testing Of Concrete PDF Download

Three commercially available instruments for testing concrete above water were successfully modified for underwater use and evaluated in laboratory and field tests. One instrument was a magnetic rebar locator that locates rebar in concrete structures and measures the amount of concrete cover over the rebar. Another instrument was a Schmidt hammer that evaluates the surface hardness of the concrete and obtains a general/condition assessment. The third instrument was ultrasonic test equipment that estimates compressive strength, detects cracks, and provides a general condition rating of the concrete based on sound velocity measurements. Laboratory and field tests did not reveal any problems with the fundamental operation of each instrument after they were modified. There was a 23% shift in the output data for Schmidt hammer as a result of the modifications, but this shift can be eliminated by designing it for underwater use. The modifications did not affect the data from the other two instruments, and all of the instruments were easily operated by a deliver. Keywords: Waterfront facilities; and Construction materials.