The Development of the Concrete Test Hammer


Fundamental Principles of Measuring Concrete
The figure shows the waveform of impact force when hammering the concrete with the CTS-02. The waveform is measured by the built-in sensor, and can be divided into two sections. The first section of the waveform up to the peak shows the time the hammer is pushing onto the concrete surface. Maximum displacement of the concrete surface occurs at the peak of the graph, when the impact force reaches its maximum value. The second section of the waveform past the peak shows the time when the displacement of concrete surface comes back to the origin. This rebound process happens through the elastic deformation energy of the concrete pushing back on the hammer. Reviewing the impact waveform in the second section, the mechanical impedance of hammer contact as the elasticity index of the concrete is measured and the strength of the concrete can be estimated from the impedance value with no damage to the concrete surface. This analysis is patented no. 3691477.