Stress wave testing of concrete: A 25-year review and a peek into the future

There are numerous nondestructive test (NDT) methods currently available for evaluation and investigation of concrete using various aspects of stress–wave propagation through the material being investigated. Some are simple “time of flight” measurements. Others are more complex methods, involving frequency analysis, measurement of energy attenuation, or capture of reflections. Regardless of their relative simplicity or complexity, all methods have evolved dramatically in the last 25 years, largely due to the evolution of the electronics industry and computer processing power. This paper reviews the more significant changes, and identifies the direct benefits to the construction and testing industries.