The purpose of this study is to investigate the correlation of the ultrasonic velocity and the compressive strength according to the strength zone. According to results of the experiments, in the results of including early age compressive strength, correlation of compressive strength and ultrasonic velocity was high. It is determined that Ultrasonic velocity in the high strength section is not significantly affected by moisture.

• 강철(한국시설안전공단 건설평가실, 선임연구원, 공학박사) | Kang, Cheol
• 장기수(한국시설안전공단 건설평가실 부장, 공학박사/기술사) | Jang, Gi-Soo
• 정광섭(한국시설안전공단 건설평가실장, 기술사) | Jung, Kwang-Sub
• 박구병(한국시설안전공단 건설안전본부장, 공학박사/기술사) | Park, Ku-Byung
• 오광진(한국시설안전공단 건설평가실 부장, 공학박사) | Oh, Kwang-Chin