PURPOSES : In this study, an eco-friendly mastic asphalt backfill material is developed to reduce production and construction temperatures by 40 ℃ compared with those recorded when using conventional hot-mix mastic asphalt backfill materials.
METHODS : To reduce the production and construction temperatures, SIS polymer modifiers and gum rosin were selected, and gum rosin-modified SIS materials were applied to the mastic asphalt binder mix design. SIS is less viscous than SBS at high temperatures owing to its thermal characteristics, and incorporating gum rosin into SIS causes the latter to exhibit a loose and soft structure. To improve the performance of the mastic asphalt modified with SIS and gum rosin, three different filler mixes, i.e., 100% PMMA, 50% PMMA and 50% calcium carbonate, and 40% PMMA and 60% calcium carbonate were applied.
RESULTS : The rosin-modified SIS reduces the viscosity of the developed mastic asphalt binders. In particular, incorporating 3.7% of gum rosin is beneficial to the mastic binder and does not degrade its low-temperature performance. Similarly, using 100% PMMA as a filler improves the performance but results in workability issues at high temperatures.
CONCLUSIONS : Rosin-modified SIS and PMMA are promising alternatives for increasing the workability at high temperatures while maintaining the target performance of grade PG82-22 binders if the appropriate ratio of calcium carbonate is mixed with PMMA and an alternative filler comprising calcium carbonate is used.

ABSTRACT
1. 서론
2. 재료설계 및 실험방법
    2.1. 재료설계
    2.2. 실험계획
    2.3. 실험방법
3. 실험결과와 분석
    3.1. 동점도 시험 결과와 분석
    3.2. 고온등급 시험 결과와 분석
    3.3. 저온등급 시험 결과와 분석
4. 결론
REFERENCES

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