PURPOSES : In this study, we propose a mini-trench method, which involves using warm mix Guss mastic asphalt as a backfill material and an installation temperature of 160 ℃. The method is verified via a heat transfer analysis of a pavement using the finite element method.
METHODS : First, the density, thermal conductivity, and specific heat required for heat transfer analysis were determined based on previous studies. Subsequently, the boundary conditions for convection and radiation to perform the heat transfer analysis were determined. The pavement temperature, which is the initial condition of the analysis, was determined based on the summer pavement temperature distribution using the temperature prediction program of the Korean pavement Research Program. Heat transfer analysis was performed by determining the temperature of the backfill material based on 160 °C and 200 °C for the heat load temperatures. The temperature change was observed on the backfill surface, and the temperature change of the conduit was observed directly.
RESULTS : When the pavement surface temperature for traffic opening is 50 °C, the backfill thickness ranges from 50 to 250 mm, the warm mix Guss mastic asphalt requires 2 h to 5 h, 15 min until traffic opening, and the hot mix Guss mastic asphalt requires 2 h, 30 min to 6 h, 40 min until traffic opening. The limit temperature of the conduit evaluated based on KS C 8454 shows that the warm mix Guss mastic asphalt does not satisfy the standard when the backfill concrete cover is 50 mm thick, whereas the hot mix Guss mastic asphalt does not satisfy the standard when the concrete cover is 50 and 100 mm thick.
CONCLUSIONS : The backfill depth of the mini-trench using warm mix Guss mastic asphalt as a backfill material should be less than 100 mm, considering the traffic opening time. Meanwhile, the thickness of the backfill concrete should be 100 mm or less.

ABSTRACT
1. 서론
2. 열전달 해석
    2.1. 열전달의 유한요소방법
    2.2. 해석모형의 구성 및 요소
    2.3. 물성
    2.4. 초기조건 및 경계조건
    2.5. 해석방법
3. 유한요소해석결과
    3.1. 되메움재 표면 온도
    3.2. 매설관 주변의 온도
4. 결론
REFERENCES

• 김영민(한국건설기술연구원 도로교통연구본부 수석연구원) | Kim Yeong Min Corresponding author