Relationship between amplitude anisotropy and compressive strength of reinforced concrete depending on curing conditions

Determination of anisotropy has crucial to assess the quality of the concrete structures. The signal amplitudes of ultrasonic wave measured on different surfaces of concrete can be used for determining the anisotropy. In this study, a total of 27 cube reinforced concrete samples with different strengths (low, medium and high) have prepared. First, signals of ultrasonic waves (P and S waves) have obtained to use direct measurement technique from two opposite surfaces of the all samples. After, Fast Fourier Transform (FFT) has applied on ultrasonic signals for determining amplitude anisotropies and amplitude ratios. Finally, amplitude anisotropies and ratios have correlated with concrete strength, porosity and reinforcement diameter depending on curing conditions and new equations have developed. In addition, these equations have determined both depending on curing conditions and regardless of curing type. As a result, it has been shown that P and S wave amplitude anisotropies and ratios of reinforced concrete increased with decreasing of concrete strength. These increasing have obtained higher for P wave than that of S wave.