PURPOSES : The objective of this study is to evaluate the effect of size and depth of cavities on the pavement failure using the full-scale accelerated pavement testing.
METHODS: A full-scale testbed was constructed by installing the artificial cavities at a depth of 0.3 m and 0.7 m from the pavement surface for accelerated pavement testing. The cavities were made of ice with a dimension of 0.5 m*0.5 m*0.3 m, and the thickness of asphalt and base layer were 0.2 m and 0.3 m, respectively. The ground penetrating radar and endoscope testing were conducted to determine the shape and location of cavities. The falling weight deflectometer testing was also performed on the cavity and intact sections to estimate the difference of structural capacity between the two sections. A wheel loading of 80 kN was applied on the pavement section with a speed of 10 km/h in accelerated pavement testing. The permanent deformation was measured periodically at a given number of repetitions. The correlation between the depth and size of cavities and pavement failure was investigated using the accelerated pavement testing results.
RESULTS : It is found from FWD testing that the center deflection of cavity section is 10% greater than that of the intact section, indicating the 25% reduction of modulus in subbase layer due to the occurrence of the cavity. The measured permanent deformation of the intact section is approximately 10 mm at 90,000 load repetitions. However, for a cavity section of 0.7 m depth, a permanent deformation of 30 mm was measured at 90,000 load repetitions, which is three times greater than that of the intact section. At cavity section of 0.3 m, the permanent deformation reached up to approximately 90 mm and an elliptical hole occurred at pavement surface after testing.
CONCLUSIONS : This study is aimed at determining the pavement failure mechanism due to the occurrence of cavities under the pavement using accelerated pavement testing. In the future, the accelerated pavement testing will be conducted at a pavement section with different depths and sizes of cavities. Test results will be utilized to establish the criteria of risk in road collapse based on the various conditions.

1. 서론
 2. 테스트베드 구축
 3. 동공생성 평가를 위한 시험
  3.1. 내시경 조사
  3.2. GPR 시험
  3.3. FWD 시험
 4. 포장가속시험 수행
  4.1. 포장가속시험장비 소개
  4.2. 응력 및 변형률 테스트
  4.3. 포장가속시험 결과
 5. 결론
 REFERENCES

• 박희문(한국건설기술연구원 도로연구소 연구위원·공학박사) | Park Hee Mun 교신저자
• 김연태(한국건설기술연구원 도로연구소 신진연구원) | Kim Yeon Tae
• 최지영(한국건설기술연구원 도로연구소 수석연구원) | Choi Ji Young
• 김기현(한국건설기술연구원 국가건설기준센터 수석연구원) | Kim Ki Hyun