PURPOSES : Recently, the generation of industrial by-products has been increased owing to the increase in electrical power consumption. This experimental study investigated a special mortar development using outstanding benefits of porous structures in heavy oil fly ash (HOFA) and bottom ash (BA) to reduce heat transfer and weight of tunnel repair mortar. METHODS : Based on the concept of materials usable for this objective being porous and light, the physical and chemical properties of heavy oil fly ash and bottom ash were analyzed to determine the application possibility for tunnel repair mortar. In addition to satisfying this primary requirement, the research aimed at determining the relationships between the characteristics of porous structures and effectiveness of reducing weight and thermal conductivity. This study was undertaken on the use of bottom ash as fine aggregate and heavy oil ash as filler in mortar mix proportion. Four different levels of bottom ash (25%, 50%, 75%, 100%, and 5%), and 10%, 15%, and 20% of heavy oil fly ash were investigated to determine the proper replacement amount within the designed specification. According to the analytic results on the effectiveness of both by-products and chemical additives, the repair mortar with optimum mixture proportion was investigated using various tests including thermal conductivity and porosity. RESULTS : The use of porous by-products increased the demand for mixing water in obtaining the required flowability, but the compressive strength did not decrease significantly in proportion by adding an amount of bottom ash. Based on the results, bottom ash can be replaced with aggregate as much as 50%, but adding an amount of heavy oil ash is suggested as below 10% in formulation. CONCLUSIONS : The optimized repair mortar, which was produced by conclusive formulation, was evaluated as a high-performance material to repair tunnels with the effectiveness of porous and remarkable physical properties.

PURPOSES : The objective of this study is to evaluate the performance of combined organic and inorganic hybrid mortar used as repair materials (UM mortar) for concrete road facilities by comparison with cement repair materials (RM mortar). METHODS: In order to produce UM mortar, four different levels of inorganic materials were adopted and the ratio of main resin to hardener was fixed at 1:2. For comparison, RM mortar made with cement repair materials was also produced. Fluidity, strength characteristics, length change, and freezing-thawing resistance of the mortars were measured at the predetermined periods. In addition, the microstructures of the mortars was performed on the 28-day mortar samples to examine the properties of the interfacial transition zone (ITZ). RESULTS : It was observed that the mechanical properties, except for compressive strength, and freezing-thawing resistance of UM mortars were much better than those of RM mortar. Furthermore, showing a densified ITZ properties on the UM mortars from the microstructural observation, the usage of UM mortars exhibited a beneficial effect on the enhancement of mortar properties. CONCLUSIONS: It is concluded that the application of combined organic and inorganic hybrid mortars is a possible option for the repair of deteriorated concrete road facilities.

This study is to analyze the causes of damage on additional facilities in road. In this study, lab test was performed using field core sample. The result of The compressive strength of concrete is met with the design regulations. However, the chloride content of in concrete increased up to 2cm. The microstructure and reactant analysis identified an expanding substance on the surface. However, as the time increases, the depth is expected to be deep.

This thesis will provide the baseline data of a suitable road repairing solution by analyzing the freeze-and-thaw resistance of inorganic-organic hybrid mortar. The resilience of polymer mortar and high-elastic mortar to freeze thaw resistance showed that the high-elastic mortar showed excellent resistanc

This research provides the baseline data for choosing the inorganic/organic hybrid material as the repairing solution by analyzing its efficiency in securing high vibration resistance and very low permeability. As a result of analysis of the mechanical properties of hybrid composite mortar, the strength increased with age. Therefore, it is considered that an inorganic binder having a certain amount or more is required for high strength development.

고체로켓모터는 점화체와 추진기관으로 구성되어있고, 추진기관에 대한 재활용 연구는 상업생산까지 이루어져 있다. 하지만 로켓모터를 처리하면서 발생하는 점화체에 (점화알약과 기폭장치로 구성) 대한 연구는 전무하여, 계속 누적되어가고 있는 실정으로, 현재 소각을 통한 처리방법만이 알려져 있다. 점화체를 구성하는 점화알약은 boron (보론, 붕소), KNO3 (질산칼륨) 및 binder인 polyester resin으로 되어있다. 이 중 붕소는 지각에 약 0.001%만 존재하는 희소성 높은 자원으로 반도체산업, 특수합금제조, 방탄유리산업 등에 이용되는 고부가가치를 지닌 물질이다. 국내의 경우 현재 수요의 대부분을 수입에 의존하고 있다. 그리고 질산칼륨의 경우 비료의 원료, 실험시약 등에 사용되는 물질이다. 본 연구에서는 유기용매 사용 또는 소결처리를 하지 않고, 순수한 물로 각 성분들의 용해도 차이만을 이용하여 질산칼륨과 붕소분말을 회수하였다. 분리한 붕소는 ICP원소분석을 통해 불순물을 확인하였고, IC분석을 통해 세척횟수에 따른 용액의 질산칼륨 회수량을 확인하였다. 점화알약에서 붕소와 질산칼륨을 순수한 물로 회수하였을 경우도 소결처리 또는 유기용매를 사용하여 회수한 경우와 금속이온들의 함량이 유사함을 알 수 있었다.