PURPOSES : The purpose of this study is to investigate the tendency of material property estimation under different concrete distress conditions and curling conditions when non-destructive tests such as rebound hammer and surface deflection test are applied to concrete pavement. METHODS : Nondestructive tests using Schmidt hammer and Falling Weight Deflectometer were performed to inspect the expressway concrete pavements constructed more than 20 years ago. Some results were compared with core tested elastic modulus and compressive strength. RESULTS : As a result of the rebound test, the section with Alkali-Silica Reaction(ASR) distress was outside the range of the existing estimation formula, but the control section was found to be within the range of the existing estimation formula. As a result of the physical property estimation through deflection test, the section with ASR distress showed greater fluctuations in the estimated material properties and deflection ratio compared to the control section, showing that the ASR damage seems to affect the slab deflection behavior. CONCLUSIONS : The rebound test may not sufficiently reflect the decline in material properties due to concrete damage. The deflection test can obtain results that reflect the deterioration of material properties, but it was confirmed that significant variability may occur, so it seems to necessary to perform complementary indoor core tests with nondestructive testing(NDT) tests.

1. 서론
2. 반발경도를 통한 물성추정
    2.1. 시험구간 개요
    2.2. 시험방법
    2.3. 시험결과
    2.4. 추가시험
3. 표면 처짐을 통한 물성추정
    3.1. 시험방법 및 시험결과
    3.2. 추가시험
    3.3. 결과분석
4. 결론

• 유태석(정회원 · 한국도로공사 도로교통연구원 연구위원) | Yoo Tae Seok (Research Fellow Korea Expressway Corporation Research Institute, 24 Dongtansunhwan-daero 17-gil, Hwaseong-si Gyeonggi-do, 18489 Republic of Korea) 교신저자