The velocity of ultrasonic wave in concrete is affected by elastic property or strength. Ultrasonic applies high voltage and sends it to transit transducer to generate ultrasonic wave. This ultrasonic wave reaches to the receive transducer through concrete. When elastic property or strength of concrete is high, the transit time is short. On the other hand, when the materials are contrary, the velocity is low. Ultrasonic measures the ultrasonic transit time accurately so it makes possible to evaluate a material or find an elastic properties nondestructively to investigate uniformity, cavities, cracks, fire/frost damage, delaminating, deterioration and strength. We use 52 khz concrete transducers which was designed to send and receive ultrasonic signal effectively in highly
extenuative materials, including concrete, wood, stone and plastic. This instrument was developed by cooperative research with research institute of standard & science, subsidized from the national coffers of ministry of science & technology. This is the 4th generation