A general method to expand the urban green space is to utilize the artificial ground that is unutilized in cities, such as buildings and rooftops. The processing technology of bottom ashes in thermal power stations shows a tendency to change from the wet process to the dry process. The dry process bottom ashes, which arise from the new process, are expected to be utilized as light-weight artificial soil, because they are poor in water, salt, and unburned carbon, which are not the characteristics of the existing wet process bottom ashes, and have a lower density than general aggregate. This study shows that the coefficient of permeability, saturation bulk density, pH, EC, and organic matter content of dry process bottom ashes are similar to those of perlite. Therefore, we conclude that dry process bottom ashes can be utilized as artificial soil.

우리나라는 총 발전량의 65%를 화력발전소에서 생산하고 있고 원자력 발전에 대한 우려로 인해 화력발전소의 비중이 커지고 있는 실정이다. 그로인해 화력발전시 발생하는 석탄재의 양은 매년 증가하는 추세이며 2011년 기준 약 710.1만톤이 발생하였다. 현재는 석탄재를 회 처리장에 단순매립으로 처리하는 수준이나 매립장의 부재와 환경오염에 의한 문제로 적절한 처리와 재자원화의 방법과 용도가 필요한 실정이다. 이에 건식공정의 바텀애시를 부족한 골재의 대체재로써 연구하고 경량골재의 이점을 통해 인공토양의 소재로써 연구하고자 한다. 본 연구는 파쇄에 의해 입도 조정된 바텀애시가 인공토양 소재로써 환경적으로 안정한지 확인하고자 토양오염공정시험기준과 pH, EC(유해물질)시험을 실시하였다. 시험은 인공토양에 사용되는 여러 소재와 비교실험을 위해 실험인자로 건식공정 바텀애시 2.5 mm 단입자, 건식공정 바텀애시 5 mm under, 펄라이트, 코코피트, 커피찌꺼기로 두었다. 커피찌꺼기의 경우 많은 배출량으로 처리가 용이하지않아 인공토양으로써의 활용을 검토하기 위해 시험하였다. 토양오염공정시험기준에 의한 실험결과 카드뮴, 구리, 비소, 수은, 납, 6가크롬 등의 중금속 항목의 경우 기준치보다 낮은 값을 나타냈고 토양으로써 사용 가능하였다. 하지만 토양오염공정시험기준의 개정사항인 석유계총탄화수소 항목의 경우 커피찌꺼기는 17,114 mg/kg으로 기준보다 높은 값을 나타내었다. pH 시험결과 인공토양 소재 모두 중성을 나타냈지만 커피찌꺼기의 경우 5.26의 산성을 나타냈다. EC시험결과 또한 커피찌꺼기의 경우 다른 소재의 4배이상의 높은 값을 보였다. 건식공정의 바텀애시의 경우 인공토양 소재로 적용가능하지만 커피찌꺼기의 경우 높은 유기물 함량과 pH, EC에 대해 사전처리가 필요하다고 판단된다.

As a fundamental analysis, this study measured and examined the mechanical property and chemical attack resistance of ceramic binder repair material at a development step through continued research. The study showed the compressive strength and bond strength of the repair material meet the standard; however, bending strength of it failed to meet the required standard. Meanwhile, chemical attack resistance displayed the excellent result.

Replacement aggregate source like as electric arc furnace slag will be important more and more in the domestic construction field. Recently KS F 4715 was revised in order to utilize electric arc furnace slag as concrete aggregate. However, stability for an actual structure has not been confirmed sufficiently. Therefore, more careful attention should be paid on the quality management of slag aggregate. To evaluate the volume stability of electric arc furnace slag, a method of immersion expansion for evaluating road aggregate has been used. These conventional method needs long time, so there are many demands from industry for fast testing method. This paper is intended to evaluate whether the acceleration test method in the hydro thermal condition is proper or not, and find the correlations between the volume expansion and oxide compounds of slag aggregate. The test results indicates that the acceleration test method has sufficient possibility as a way of evaluating the safety of electric arc furnace slag, and that there is no correlations between the volume expansion of mortar bar with slag aggregate and the oxide compositions of slag aggregate, but the main cause of the pop-out phenomenon is the MgO content of slag aggregate.

For utilization of Electric Arc Furnace Slag’s high added value, KS F 4571 was revised, so the institutional environment to use concrete aggregate was prepared. But, it has hardly been reported how much the slag occurring in actual steel-making plants meets KS requirements. Therefore, this study was intended to analyze various engineering features of electric arc furnace slag, which occur in diverse kinds of electric arc furnace process to manufacture reinforcing rebar, hot roll, and shape steel, in accordance with KS and relevant standards. The test results from this study showed that electric arc furnace slag occurring in Korea didn’t meet the standards relating to many physical properties, such as water absorption, grading, unit volume weight, and material passing standard sieve 0.08 mm which are required for concrete aggregate and are prescribed in KS F 4571, and therefore that something is needed to be improved. Regarding chemical properties, heavy metal solubility based on official wastes test method, CaO and FeO were met, but content of MgO related to expansion and basicity exceeded or came close to standards. Therefore, it was found that some measures should be taken to address the issue.