Nowadays, almost infrastructure in Thailand are almost reinforced concrete (RC) structure because they are strong and durable enough against environmental changes; nevertheless, the concrete durability will be decreased. The proper concrete integrity survey for potential remedy works is very importance, Thus, this research aims to inspect flaws especially delamination and air-filled void by four Non-Destructive Testing (NDT) methods be composed of 1) ultrasonic pulse velocity (UPV), 2) ultrasonic pulse echo (UPE), 3) impact echo (IE), and 4) ground penetrating radar (GPR). Furthermore, this research is separated two parts be consisted of idealized structures simulated defects and a realistic structure. The changing of siganal patterns and parameters are performed on idealized structures along the hardening peroid is used for guidance to the realistic structure and verified an accuracy by core sampling method. The research results are shown that the accuracy, precision, suitability, and performance of GPR and UPE method are better than the other methods. Although, the GPR method is sensitive with water content in an early concrete while the UPE method is not, the real case of flaw inspection is normally performed at an older concrete. Moreover, the data acquisition and interpretation of them were not used too much time in the same testing area.