PURPOSES : The frequency and severity of natural disasters such as torrential rain or typhoons have become increasingly significant worldwide. Events such as summer typhoons and localized torrential downpour can cause severe damages to a residential area and road networks, resulting in serious harm to the daily lives of people, especially in rural areas by isolating residents from road networks. An immediate and emergency repair technology for the collapsed road networks is urgently needed. This study introduces a new technology to repair road bases or slopes. METHODS: The development of new technology for emergency and permanent repair consists of first, packing of cement paste-coated gravel, second, combining appropriate equipment, and third, conducting a field applicability test. In this research, the compressive strength of cement pastecoated gravel, gravel-netting concrete properties, and packing efficiency were determined, and a full scale field mock-up test was carried out. RESULTS : The compressive strength of the cement paste-coated gravel concrete satisfied the required limit for road base of 5 MPa after 7 days. With appropriate netting materials and packing size, gravel-netting concrete was successful up to a slope of 1:1.5. The full scale field mockup test showed efficiency in the field and penetration resistance performance. CONCLUSIONS: The new technology of emergency and permanent repair for damaged road bases and slopes, introduced in this study, showed satisfactory performance. The technology is expected to be applied in the field when construction procedures and quality specifications are made.

최근 호우 및 산사태 등 자연재해로 인한 도로유실 피해가 증가하고 있으며, 특히 지역특성상 산림이 많이 분포된 지역은 피해가 큰 실정이다. 또한, 유실부 긴급복구 방법은 일시적 교통개방이며, 지속된 교통개방이 어려운 상태이다. 이에 본 연구에서는 도로유실 긴급복구를 위한 연구의 일환으로 골재망을 활용한 다공질 콘크리트 긴급복구 공법의 장비조합을 제안하고자 하였으며, 최소한의 장비로 현장배합 및 도로유실 긴급복구에 활용하고자 한다. 장비, 재료 운반 및 하차수단으로 카고크레인 및 일반 적재트럭으로 2식의 차량을 제안하며, 운반 구성은 현장배합용으로 시멘트, 몰탈믹서, 1㎥물통과 유실부 복구를 위한 골재망, 시멘트페이스트 적재 박스와 골재망 적치는 카고크레인으로 대처하며, 현장지반정리용 0.2B/H, 다공질콘크리트 일부다짐용 콤펙터를 활용하였다. 그림1 및 그림2는 제안한 2식의 차량으로 활용되는 계획을 각각 나타내며, 그림3은 제시한 장비조합의 긴급복구 계획을 나타내고 있다. 도로유실 긴급복구 골재망 활용 다공질 콘크리트의 현장배합 및 시공을 위한 장비조합을 제시하고자 하였으며, 이에 따른 결과는 다음과 같다. 1) 제시한 장비조합은 대형 중장비가 아닌 중 · 소형 장비, 재료로써 운반 및 사용이 용이하며, 신속하고 항구적인 골재망 활용 다공질콘크리트 긴급복구 공법에 적합하다 판단된다. 2) 제시한 장비조합은 Mock-up시험 등을 통한 검증필요가 예상되며, 유실위치 및 규모에 따른 추가 장비구성 및 시공방법 변경에 대한 추가적인 계획이 필요할 것으로 사료된다.

PURPOSES: As a part of our research into repair techniques for roads that have collapsed as a result of a natural disaster, this study set out to find the optimum mix proportion for gravels to be used to restore a damaged area. METHODS: This study considered flow and strength-development characteristics. The experimental variables were the W/C ratio, the usage of the admixture, the types of cement, and the quantity of fine aggregate over three different experimental stages. The compressive strength was measured at 12 hours, one day, three days, and seven days. RESULTS : The flow varied with the amount of fine aggregate and the use of a high-range water-reducing (HRWR) admixture. The compressive strength also varied with respect to the type of cement and the W/C ratios. The strength satisfied the expected requirement of 21 MPa after one day, provided the mix proportion was appropriate. CONCLUSIONS: A gravel-filling high-flow cement-based mortar exhibited strength and consistency with a W/C ratio in the range of 0.40 to 0.45, assuming the use of HRWR at 0.5 to 0.7% and a fine aggregate/cement ratio of 1.0 to 1.5.