Concrete plate thickness measurement using the indirect impact-echo method

A new method for measuring the thickness of concrete plates indirectly is proposed. In this approach, a steel ball impacts on a steel bar and the generated stress waves transfer to the concrete plate. Numerical simulations of the process were carried out using different plate thicknesses. The results indicate that the impact response of the concrete plate for a dominant thickness frequency in the indirect method agrees with the results obtained in the classic direct method in which the impactor collides directly on the specimen being tested. The results also show that the proposed method can be used to measure the thickness of concrete plates with reasonable accuracy. The behaviour of stress waves in the steel bar was investigated and revealed to be consistent with previous research.