PURPOSES : This study was conducted to evaluate the performance of pressure relief joints (PRJs) installed on highways for preventing blow-ups.
METHODS : To evaluate the performance of a PRJ, pavement surface images were acquired by conducting a follow-up survey through on-site visual inspection and an automated pavement condition survey. The PRJ widths in the acquired pavement images were measured using image analysis software, and major distress in the PRJ was identified. The relationship between the performance period and the joint width was bi-linearized, and the causes of distress and repair methods for PRJ were suggested.
RESULTS : As a result of the first survey, it became known that the width of a PRJ rapidly decreases after installation owing to an expansion of the concrete slab. The width of a PRJ continued to decrease, with 94% of the joint below 30 mm and 64% of the joint being below 10 mm, based on the fourth survey. The PRJ width of an Alkali-Aggregate Reaction (AAR) section decreased more than that of a normal section, but the difference in the average width between both sections decreased from 9.7 mm to 2.7 mm over the measured period. A bilinear estimation equation was developed based on the survey data. Through the estimation equation, it could be confirmed that joint contraction accelerated after installation owing to the effects of AAR, and that the joint widths of both sections converged to a similar level over the measurement period. As the result of the major distress analysis indicates, joint seal failure occurred in 70% of the joints, and the distress rates in terms of cracks, edge breakouts and spalling, and patching were 73%, 57%, and 28%, respectively.
CONCLUSIONS : With the follow-up survey it could be confirmed that the concrete slab continued to expand despite seasonal changes, maintenance of the PRJ, and additional installation of new PRJs. The expansion of the concrete slab due to AAR is considered to be closely related to PRJ behavior. In addition, it is judged that major distress of the PRJ occurs at an early age owing to the instantaneous release of excessive compressive stress inherent in the slab during joint cutting.

ABSTRACT
1. 서론
2. 선행연구 조사
3. 추적조사 현황 및 공용성 평가 방법
    3.1. 추적조사 구간 현황
    3.2. 공용성 평가 방법
4. 응력완화줄눈 공용성 평가
    4.1. 추적조사 결과
    4.2. 공용기간과 줄눈 폭의 상관관계 분석
    4.3. 주요 파손 분석
5. 결론
REFERENCES

• 박양흠(금오공과대학교 토목공학과) | Park Yang Heum
• 류성우(한국도로공사 도로교통연구원) | Ryu Sungwoo
• 장일영(금오공과대학교 토목공학과) | Jang Il Young
• 김태수(㈜로드코리아 기술연구소) | Kim Tae-Soo 교신저자