The Chloride ion penetration resistance of Engineered cementitious composite using surface coating material was evaluated in this study. The test results showed that the amount of chloride ion of surface coated specimens were decreased approximately 22 % lower than that of plain specimens

In this study, to evaluate the performance of fire resistance of the mortar with magnesium hydroxide(MH) and aluminium hydroxide(AH) which has a RCC (Radiant Control Capability) as repair material to the steel structure, temperature evaluation of mortar was conducted by increasing 500°C in the furnace. The performance of RCC can decrease a temperature to external and internal mortar. As a result, it is confirmed that temperatures of mortar with magnesium hydroxide(MH) and aluminium hydroxide(AH) were more decreased than general mortar due to the RCC effect of MH and AH. Therefore, it can be possible to apply to a repair material at the steel structure.

This study provides experimental results of pH restoration of acidified desulfurization seawater by the addition of the alkalinity enhanced seawater and additives (limestone and fly ash). The conservative seawater desulfurization processes use chemical solutions such as caustic soda (NaOH) or calcium hydroxide(Ca(OH)2). The method proposed in this study was aimed at reducing usage of chemicals. A control test was conducted to simulate the existing process without addition of the alkalinity-enhanced seawater and additives (limestone and fly ash). The pH of desulfurized seawater was increased by pH 5.84 through the conservative restoration process (i.e., adding raw seawater and NaOH solution followed by aeration). The 20%, 50%, and 80% of added raw seawater was replaced by the alkalinity-enhanced seawater. From the experimental result, 0.28, 0.89, and 1.05 m3/hr of 48% NaOH solution could be saved when applying the proposed method of the alkalinity enhanced seawater addition. When desulfurized seawater with pH 3.5 was mixed with raw seawater at a ratio of 1:1, the pH of seawater was increased up to pH 6. Therefore, the seawater restoration goal was set as pH 3.5. Experiments were conducted to increase pH of desulfurized seawater to pH 3.5 using additives (fly ash and limestone). Based on these results, the addition of fly ash and limestone to seawater was proved effective for pH restoration of desulfurized seawater.

In order to measure the rheological behavior of precast concrete with high volume of recycled fine aggregate, the replacement of natural fine aggregate by recycled one was carried out in dry-mix process. As results of that, it was found that as the replacement increases, strength and performance of concrete become decreased but may be recoverable by proper selection and dosage of constituents.

Connecting members are proposed to skip installing formworks in the process of assembling the slab type precast modular bridge. In this study confirms the field applicability of connecting members for rapid construction of slab type precast modular bridge.

This study evaluates the material performance of slump value and compressive strength of the concrete which was made by recycled sand and blast furnace slag powder(BFSP). The main variables are replacement ratio of BFSP. As a result, it was evaluated that more detailed evaluation is needed in long-term strength development and the compensation of slump value to the replacement ratio of BFSP.

This study propose the embedded sensing system for tensile force estimation of PSC tendon using FBG and EM sensors. Through experimental study, it was found that the tensile force can be estimated by measuring the strain and permeability using proposed sensing system.

Effects of recycled fine aggregate on the behavior of cement-based concrete were evaluated with different compressive strengths through experiments. It can be observed that recycled fine aggregate can be useful to fabricate precast concrete products in terms of having of concrete strength equivalent to natural aggregate.

In order to identify the nature of recycled fine aggregates, an experiment was conducted by mixing recycled fine aggregates. Then, comparative analysis was carried out throughout compressive strengths obtained from steam curing and water curing methods. The concrete mixed with recycled fine aggregate has low strength gain compared to the conventional concrete. But in case that concrete produced in dry process is applied to precast concrete prod

Recently, in Seoul there is a growing interest in the L type gutter between the street and the sidewalk because the broken gutter spoils the appearance of the city. The gutter has been viewed as an unimportant attached facility of the road despite an important drainage facility. Also, the gutter lost function by various deterioration actions is becoming hideous objects of streets. Accordingly, many engineers recognized problems about the gutter and tried to seek for solution. In this study, we desired to confirm that the inside of the gutter concrete was not deteriorated even if the surface of the gutter concrete was deteriorated by the de-icing salts. We could obtain thirty core specimens deteriorated by de-icing salts in Seongbuk-gu which is old downtown, has many hills such as Arirang-Hill, Miari-Hill, etc. in Seoul and test compressive strength. It was confirmed that the compressive strength of the gutter concrete follows normal distribution and it is statistically significant 1% level that the population mean of the compressive strength of the gutter concrete is more than 18MPa.

This paper was examined the durability properties of concrete using rapid cooling slag as fine aggregate for concrete. The results of experiments, concrete using rapid cooling slag showed that durability properties was equal to concrete using normal fine aggregate.

급격한 산업화와 삶의 질의 변화로 인해 생산된 고밀도 폐유리의 양은 꾸준히 증가하고 있으나 대부분 재활용되지 못하고 있다. 특히 고밀도 폐유리의 경우 불법적으로 처리되거나 매립되는 실정이다. 한편, 원전구조물의 안전성 확보를 위해 차폐 성능이 우수한 재료가 사회적으로 요구되고 있다. 콘크리트는 가장 많이 사용되고 있는 건설재료이며, 많은 양의 자원들이 콘크리트를 생산하기 위해 사용되고 있다. 따라서 고밀도 폐유리를 차폐 콘크리트 재료로 재활용할 수 있는 방안에 대한 연구가 요구되어진다. 본 연구에서는 고밀도 폐유리를 차폐 콘크리트 잔골재로의 적용가능성을 평가하였다. 결과에 따르면, 폐유리를 혼입한 모르타르의 경우, 일반 모르타르에 비하여 단위용적질량이 증가하여 차폐 성능 개선이 가능할 것으로 판단된다. 폐유리 혼입에 의해 강도는 감소하는 것으로 나타났으며, 세척의 경우보다 비세척의 경우에 강도 발현이 유리한 것으로 나타났다.

The experience of natural dyeing is expected to be effective in promoting health through good exercise, in giving emotional stability based on the functional aromatic components of the dyeing material, and in improving self-esteem and increasing positive experiences through the behavior of creation. A natural dyeing material easily found around us, artemisia has long been used in food and Oriental medicine and was recently found to contain antioxidative, anticancer, deodorizing, antibacterial, anti-obesity, and anti-diabetes substances through chemical analysis. It has also been reported that group reminiscence therapy using the fragrance of artemisia is effective in relieving pain and depression and in promoting ego integrity in the elderly population. This study aimed to make a comparative analysis of dyeability, washing fastness, and deodorization between Artemisia princeps, Artemisia iwayomogi, and Artemisia annua, all of which are considered to be healthful and functional dyeing materials, among about thirty domestic plants in the genus of Artemisia and to provide basic data concerning natural dyeing in mind-peace education for the silver generation. The fabric dyed and post-mordanted at 80℃ for 40 minutes showed the greatest surface color variation; in this condition, artemisia princes (32.29) gave the greatest color difference, followed by artemisia iwayomogi (31.07) and artemisia annua (26.17). While all the types of artemisia were excellent in washing fastness, dry-cleaning fastness, and rubbing fastness at the fourth- or fifth-grade, light fastness was at the third grade for artemisia princes, at the second to third grade for artemisia annua, and at the second grade for artemisia iwayomogi; therefore, artemisia princes was found to give better fastness than the other two types of artemisia. In determining functionality of the fabric dyed with artemisia, deodorization test also found that the fabric dyed with artemisia princes had 20% higher deodorization.

In this study, sulfuric acid resistance of sulfur polymer surface protected concrete was evaluated. From the test result, the case of the surface protected test specimen showed no degradation of the concrete surface. Therefore, it is considered as applying on waste water disposal plants, drainage pipelines, etc is possible.

This paper was examined the mechanical properties of concrete using rapid cooling slag as fine aggregate for concrete. The results of experiments, concrete using rapid cooling slag showed that mechanical properties was equal to concrete using normal fine aggregate.

Effects of recycled fine aggregate on the behavior of cement-based mortar were evaluated with different compressive strengths through experiments. It can be observed that recycled fine aggregate can be useful to fabricate precast concrete products in terms of having mortar strength equivalent to natural aggregate.

PSC continuous girders have been used to improve the stability of simply supported girders. The loss of prestress is one of important factors for rational design and construction of the PSC girders. Measurements of prestress loss were conducted with the several test variables that reflect the conditions of continuous joint. Results show that the prestress loss is closely related to a eccentricity.

Among many types of flue gas desulfurization (FGD) facilities, wet type FGD using lime or limestone is most popular in the world because of its simplicity of operation and availability of lime and limestone. Seawater desulfurization utilizes the alkalinity of seawater, thus requires no addition of lime and limestone. The efficiency of seawater desulfurization depends on the variation of alkalinity of seawater at different locations. This study presents the effect of gas-water ratio and total alkalinity of absorbing solution on the removal efficiency of sulfur dioxide from the flue gas by means of seawater. Also this study provides an alternative way to increase total alkalinity of seawater by utilizing fly ash from coal-fired power plants. The increase of removal efficiency with increase of alkalinity was measured as 0.26 ± 0.01% per ppm of bicarbonate alkalinity from the set of experiments using seawater, underwater, and distilled water, the alkalinity of which were 111 ppm, 38 ppm, and 1 ppm, respectively. Capability to increase total alkalinity of seawater using fly ash was confirmed.

하수슬러지는 2006년 발표된 국토해양부 ｢육상폐기물 해양투기 관리 종합대책｣에 의거 2012년부터 해양배출이 전면 금지되었다. 2012년 하수슬러지 해양배출 전면 금지에 따라 규정에 의거 매립이 가능한 함수율 75%이하 슬러지는 금고동 매립장에 매립(일 최대 80톤) 건의, 잔여량(함수율 75% 초과)은 민간 폐기물 재활용(복토재 생산)업체에 위탁처리하고 있다. 처리비용 절감을 위한 위탁처리 부산물의 금고동 매립장 복토재 활용 검토와 슬러지 안정적 처리 방안 등을 도출하기 위해 이번 연구를 실시하였다. 본 연구의 내용 및 범위는 민간 폐기물 재활용업체에서 생산된 하수슬러지 부산물의 매립장 복토재 활용 방안이며, 고화토의 기본 물성을 실험하고 역학특성을 평가하여 연구를 진행하였으며 비중시험, pH시험, X-선 형광분석을 이용하여 물성을 실험하였다. 역학특성 평가는 수분함량측정, 일축압축강도시험, 투수시험, 악취시험을 통하여 평가 하였다. 고화물의 복토재 품질 검토 결과 고화처리물의 품질기준에는 만족하여 포설은 가능하나 악취 발생이 심각하여 민원 발생 가능 및 작업자의 안전에 위협을 주므로 반입 가능성은 매우 낮은 것으로 나타났으며, 향후 건조 연료화 시설의 건설/운영 전까지는 다수의 슬러지 처리방법 중 직매립과 고화 복토 방법이 가장 경제적이고 기술적으로 타당한 것으로 판단된다.

전국의 2012년도 가축분뇨 발생량은 <표 1>에서 보듯이 46,489천톤이 발생하였다. 2012년도부터 가축분뇨의 해양투기가 전면금지 되었기 때문에 전량 육상처리하고 있으며, 이 중 퇴비로 처리되는 량이 81%로 가장 많이 차지한다. 한편, 충남 보령시는 가축농가가 차지하는 비율이 높은 편이며 가축사육시설 및 가축분뇨 처리과정에서 발생하는 악취로 인한 민원발생이 많은 지역이다. 가축분뇨는 2,055톤/일 발생하며 이중 퇴비로 처리되는 양이 68%이다. 가축분뇨는 2012년부터 해양투기가 전면금지 됨에 따라 전량 육상 처리되고 있으나, 가축농가의 분뇨처리시설용량 부족으로 및 가축분뇨 부적정 처리로 인한 악취발생, 환경오염 문제가 발생하고 있다. 가축분뇨를 자원화하는 것은 유용한 자원으로 소득에 기여할 뿐만 아니라 폐기물을 발생시키지 않아 환경을 보전하기도 한다. 최근 국내의 가축 사육 규모가 커짐에 따라 가축분뇨의 처리문제와 악취로 인한 민원이 증가하여 사화문제화 되고 있다. 악취민원은 2003년 이후 연평균 14.5% 증가하고 있고, 축산관련 악취는 약 7%로 해마다 지속적인 증가를 보이고 있다(환경부, 2007). 축종별로 보면 양돈 관련 악취 민원이 약 54%로 많은 부분을 차지하고 있다. 퇴비는 음식물쓰레기, 축산분뇨 등을 발효 및 부숙시켜서 농작물, 원예, 임야에 시비하는 것이다. 퇴비 생산시에는 음식물쓰레기 및 축산분뇨와 같은 퇴비대상물이 수분이 85%정도로 높아 부패하기 쉽기 때문에 퇴비에 적합하도록 수분조절재(톱밥, 왕겨등)를 사용하여 수분을 60~65%로 조절하여야 한다. 퇴비는 퇴비대상물이 함유한 유기물을 분해 안정화시켜서 토양미생물의 활성을 도와주는 역할을 하며, 퇴비 조건이 맞지 않을 경우 발효가 잘 일어나지 않거나 악취가 많이 발생되기도 한다. 이러한 경우 퇴비의 발효를 촉진시키기 위하여 발효촉진재를 첨가하여 퇴비화가 원활하게 진행하게 한다. 시판되고 있는 퇴비 발효제는 대부분 미생물제로써 토양이나 유용한 미생물을 추출, 배양하여 주로 액상으로 공급하고 있다. 개발된 기술은 퇴비 발효촉진재로써 미생물제가 아닌 무기물로 구성된 미생물활성재이다. 본 퇴비 발효촉진재는 퇴비대상물(가축분뇨+톱밥)에 5%정도 혼합하면 악취발생이 거의 없고 고온이 장기간 지속되어 완숙퇴비가 되게 만들어주는 기능을 가지고 있다. 구체적으로는 발효촉진재의 성분에 의해 폴리실리케이트 망목을 형성하여 악취물질을 흡착하는 기능이 있어 악취를 70%정도 억제하는 기능, 친수성 수화물질의 수화반응 및 경화반응에 의한 수분증발 기능, 발효촉진제는 약알칼리성으로 퇴비를 시비할 경우 산성토양을 중화시키는 기능, 초기발열 및 고온균 활성화로 퇴비기간을 기존의 50일에서 40일로 약20% 단축시키는 기능, 고온균 및 방선균 활성화 및 고온 장기지속 등으로 완숙퇴비를 만들어 주는 기능을 가지고 있다. 따라서 발효촉진제가 비록 분말이지만 단립화기능이 있으므로 첨가량 만큼 톱밥 사용량을 줄일 수 있다. 발효촉진재의 용도는 퇴비 첨가물로써, 가축분뇨 및 음식물쓰레기 등을 퇴비화 할 경우, 가축분뇨 및 음식물 쓰레기에 톱밥을 혼합 한 후 추가로 발효촉진재를 무게비로 5%정도 혼합해 주면 된다. 따라서, 본 사업을 통해, 화력발전소에서 발생하는 바텀애쉬 및 공장의 폐흡착제는 충 발효촉진재의 대체원료로의 사용함으로써, 바텀애쉬 및 폐흡착제의 재활용 수요처를 확보함과 아울러 부산물처리 비용의 절감효과를 기대할 수 있다. 아울러, 생산업체에서는 발효촉진재의 대체원료 활용을 통해 안정적인 수급과 원가절감 효과를 기대 할 수 있다. 폐기물 자원화 네트위크 구축사업으로 생산되는 발효촉진제는 가축농가 퇴비장에 지원하여 악취문제를 근원적으로 해결함으로써 지역 편익을 증진시킬 수 있는 사업이다.