This study aimed to manufacture emulsified asphalt for free-heated asphalt mixtures with high solid contents using the high internal phase ratio (HIPR) technique and utilize it as basic research data by evaluating the basic properties. The optimal emulsifier was selected by considering the physical and chemical properties of the emulsifier used in the emulsified asphalt, and the solid content in the emulsified asphalt was increased using the HIPR technique. Emulsified asphalt was produced with solid contents of 90%, 80%, 70%, and 62% (current standard) in emulsified asphalt, and the basic properties of the emulsified asphalt were evaluated for each content. In addition, a free-heated asphalt mixture for the surface layer was produced by applying the emulsified asphalt produced for each content, and the performance was evaluated based on the quality standard items presented in the current guidelines of the Ministry of Land, Infrastructure and Transport. When utilizing the HIPR technique, we could manufacture up to 90% of the asphalt solid content in the emulsified asphalt; however, applying it to unheated asphalt mixtures because of the increase in viscosity was impossible. We determined that it could be applied up to a maximum solid content of 80%. In addition, in the free-heated asphalt mixture test, the ratio of the air void increased as the solids content increased, but the strength decreased. An examination of the fracture surface after the strength test revealed that it was brown, which is a characteristic color of emulsified asphalt. This was because the curing time became insufficient as the solid content increased, resulting in insufficient time for strength development. To ensure the performance of the free-heated asphalt mixture, we observed that the viscosity of emulsified asphalt with a high solid content should be reduced; securing the curing time accordingly was an important factor, and it was determined that additional research is necessary.

온실가스 배출량을 최소화하기 위하여 가열 없이 생산이 가능한 상온 아스팔트 포장 공법도 2000년 초부터 개발되어 활용되고 있으 나, 기술적 한계로 인해 성능 확보가 어려워 대부분 기층용으로 활용중에 있다. 상온 아스팔트 혼합물은 유화아스팔트를 사용하는데 양생하는 동안 혼합물 내부에 있는 물이 증가됨에 따라 혼합물 내부의 높은 공극률이 발생하게 되어 포장의 성능을 확보하는데 한계 가 있다. 따라서 본 연구에서는 유화 아스팔트 내 아스팔트 고형분 함량을 증가시켜 물 함량을 최소화함으로서, 양생시간을 단축하고 낮은 공극률 확보를 통한 상온 아스팔트 혼합물의 성능의 변화를 평가하였다. 시험결과, 고형분 함량이 변화에 따라 공극률 및 간접인 장강도, 터프니스 물성이 변화가 나타났다. 하지만 고함량 고형분의 유화 아스팔트를 상온 아스팔트 혼합물에 적용하기 위해서는 최적 함수비 결정방식 및 양생방식 등에 대한 추가적인 연구가 필요한 것으로 나타났다.