• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.453-460
• /
• 2004

To prevent penetration of rainwater into the landfill site is the main purpose of the final cover in landfill sites. Conventional designs of landfill covers uses geotextiles such as geomembrane and GCL, and clay liners to lower the permeability of final covers of landfill sites. However, differential settlement and the variation of temperature in landfill sites cause the development of cracks or structural damage inside the final cover and it is also difficult to obtain clay - the main material of the compacted clay liner in Korea. Thus the former final cover system that suggests geomembrane and GCL or compacted clay liner has several limitations. Therefore, an alternative method is necessary and one of them is the application of SRSL(self-Recovering Sustainable Liner) material. SRSL is two different layers consist of individual materials that react with each other and form precipitates, and with this process lowers the permeability of the landfill final cover. SRSL generally is made up of two layers, so that when a internal crack occurs the reactants of the two layers migrate towards the crack and heal it by forming another liner. In this study the applicability of SRSL material for landfill final cover was examined by performing; (1) jar test to verify the formation of precipitate in the mixture of each reactants, (2) falling head test considering the field stress in order to confirm the decrease of permeability or prove that the hydraulic condctivity is lower than the regulations, (3) compression tests to judge weather if the strength satisfies the restricts for landfills, (4) freeze/thaw test to check the applicability of SRSL for domestic climate. In addition, the application of waste materials in the environmental and economical aspect was inspected, and finally the possibility of secondary contamination due to the waste materials was examined by performing elution tests.

• 한국도로학회논문집
• /
• 제13권2호
• /
• pp.159-166
• /
• 2011

본 논문은 에폭시 계열의 폴리머 콘크리트 교면포장 공법의 국내 적용 가능성을 검토하기 위하여 교면포장용 폴리설파이드 에폭시 재료에 대한 물리 역학적 특성을 평가하기 위하여 수행하였다. 강도특성을 평가하기 위하여 압축강도, 휨강도, 접착강도 시험을 수행하였으며 내구특성 평가를 위하여 염소이온침투시험, 동결융해저항성시험, 자외선영향 평가를 실시하였다. 시험결과 압축강도, 휨강도, 접착강도 등은 미국콘크리트협회에서 제시하는 기준을 만족하는 것으로 평가되었다. 그러나 다양한 시험온도에서의 강도 시험결과에서 에폭시 재료가 온도 의존성이 큰 것으로 나타나 향후 국내 적용시 이에 대한 고려가 필요할 것으로 판단된다. 휨강도 시험을 통한 처짐에 대한 추종성은 기존 아스팔트 교면포장에 비해 우수한 것으로 평가되었다. 또한 염소이온침투 저항성, 동결융해 저항성 등에 대해서도 우수한 성질을 가진 것으로 평가되었다. 에폭시 슬러리 혼합물에 대한 자외선 영향 평가에서는 강도 증가와 파괴시 변형률 감소가 나타났으나 자외선 노출 후에도 기존 아크릴계 폴리머 콘크리트보다 처짐에 대한 추종성이 양호한 것으로 평가되었다. 따라서 폴리설파이드 에폭시 재료가 교면포장 공법으로 사용하기에 적절한 물리적 특성을 가지고 있다고 판단된다.

• 한국응용과학기술학회지
• /
• 제39권1호
• /
• pp.52-62
• /
• 2022

소변검사 전 냉/해동 반복과 해동 과정에 따라 대표적인 임상 화학검사 측정값의 변화를 확인함으로써 소변검사의 안정성과 품질 개선방안을 모색하고자 하였다. 조사 대상자는 모두 건강한 남성 10명이었으며 이들의 소변 검체를 이용하여 냉/해동 안정성(freeze and thaw stability) 실험을 진행하였다. Micro-albumin과 Amylase의 경우 시간이 경과 됨에 따라 37℃에서는 통계적 유의성은 없었으나, 42℃와 60℃에서는 시간의 경과에 따른 결과가 통계적으로 유의한 변동이 있었고, BUN, Creatinine, Uric acid와 Glucose에서는 통계적으로 유의한 변동이 있었다. Long term의 안정성 결과, 7일이 지난 후에는 Glucose의 변이는 증가하였고, 60℃에서는 Amylase가 감소하는 양상을 보였다. Glucose와 Amylase의 경우 시간의 경과에 따른 결과가 통계적으로 유의한 변동이 있었다. 신뢰성 있는 검사결과를 얻기 위해서는 소변 시료의 채취, 보관 및 저장 등을 비롯한 요검사의 정확한 표준화가 필요하며 생체 물질별 안정성 확보를 위한 조건들의 체계적 연구가 필요하다.

• 한국도로학회논문집
• /
• 제4권1호
• /
• pp.161-170
• /
• 2002

본 연구는 폐폴리에틸렌필름(폐비닐)을 아스팔트 혼합물에 첨가하여 아스팔트 포장재료의 품질특성을 향상시키고 환경적으로 문제가 되고 있는 폐비닐을 재활용하기 위한 연구의 일환으로 수행되었다. 폐비닐 사용시 나타날 수 있는 포장체의 특성을 파악하기 위하여 국내에서 가장 많이 수거되는 LDPE 폐비닐을 사용하여 현장에서의 실용성을 고려한 건식혼합법으로 아스팔트 혼합물을 제조하였다. 제조한 혼합물에 대하여 마샬안정도 시험, 간접인장강도 시험, 반복주행시험 및 피로시험을 수행한 결과 폐비닐을 혼합한 혼합물이 일반혼합물에 비하여 인장강도가 향상되고 윤하중에 의한 소성변형 저항성 및 피로균열 저항에 크게 효과적인 것으로 나타났다.

• 동력기계공학회지
• /
• 제9권2호
• /
• pp.50-56
• /
• 2005

The mechanical properties of glass fiber reinforced polymer reinforcing bars(rebar) in various environment conditions such as moisture, chloride, alkali and freeze-thaw actions at temperature ranging from room temperature($25^{\circ}C$) to high temperature of up to $80^{\circ}C$ have been studied. The test results indicated that tensile strength and interfacial shear strength of GFRP bar were decreased with the increasing of temperature and holding time of each environment condition. The degradation in alkali environment. was more serious than those in the other environments.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
• /
• pp.433-438
• /
• 2000

The purpose of this study is to examine the resistance of water-permeable concretes to freezing and thawing action. The water-permeable concretes with cement-aggregate ratio of 1:5.5(by weight) and two kinds of admixture content [SP : superplasticizer(0, 1.0%), HPAE : high performance air entraining agent(0.5, 1%)] used OPC(ordinary portland cement) as binder were prepared, and then tested for relative dynamic modulus of elasiticity, mass change, length change and durablity factor. It's been concluded from the test results that the superior relative dynamic modulus of elasiticity and durability factor of water-permeable concretes were obtained at superplaciticizer 1.0% after 300 cycles. The water-permeable concretes used superplasiticizer 1.0% having relative durability factor of 88% after 300 cycles.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.78-81
• /
• 2003

Recently, physical properties of concrete containing ternary blended cement were actively researching to develop durability, mobility, and atc. as well as strength increase of concrete. In this study, durability of concrete such as the resistance against chloride ion penetration, rebar corrosion, freeze and thaw, and sulfate were researched for concrete containing ordinary portland cement(OPC) and ternary blended cement(TBC), respectively. For this purpose, concrete specimens containing OPC and TBC, respectively, were made for 37.5% of W/C, and then various durability experiments described above were carried out. As a result, it was observed from the test that concrete containing TBC showed excellent durability than concrete containing OPC.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
• /
• pp.285-291
• /
• 1998

During recent years, the durability of concrete structures has been considered in concret practice and material research. To preserve the brittleness of concrete as well as energy absorption and impact resistance, amount of fiber usage has greatly increased in the field of public works. Ultra fine powder, silica fume, mixed into concrete, it reduce void of concrete structure. Especially, there's a great effect for strength improvement of concrete by initial pozzolanic reactions. For these reasons, if silica fume mixed into concrete, it decrease the total void by microfilter effect . Pozzolan reaction, between cement particle and silica powder, can elaborate the micro structure of matrix. And so, in this paper, we deal SFRC for the purpose of efficiently using of industrial by-products(silica fume). Also we performed the test for durability such as freeze-thaw resistance and accelerated carbonation of SFRC using silica fume.

• Corrosion Science and Technology
• /
• 제4권5호
• /
• pp.207-210
• /
• 2005

Coating performance of various coating systems including chlorinated rubber and epoxy/urethane used most for steel structures of highway in Korea, was evaluated by exposing test specimen to complex deterioration factors such as ultraviolet ray, moisture, freeze-thaw cycle and salt. Deteriorated specimens were evaluated by chalking and rust grades according to ASTM, and measurement of color differences and adhesion. In overall coating performances such as corrosion resistance, photochemical stability, and adhesion, ceramic/ urethane, moisture-curable urethane/ urethane, etc. were superior. As for other coating materials tested in this study, superior materials against certain deterioration factors may be inferior against other factors. Accordingly, in order to select suitable maintenance coating materials for the use, it is thought that investigation of suitability through experiment should precede selection of materials, especially for unusual coatings or paints.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
• /
• pp.339-344
• /
• 1997

During recent years the durability of concrete structures has attracted considerable interest in concrete practice, material research and long-term deformation. To preserve the brittleness of concrete as well as energy absorption and impact resistance, amount of fiber usage has greatly increased year to year in the field of public works. When fly ash, fine powder, mixed into concrete, it condensed the void of concrete structure. Expecially, there's a great effect for strength improvement of concrete by initial pozzolanic reactions. Pozzolan reaction, between cement particle and fly ash, can elaborate the micro structure of matrix. So it was able to improve the effect of fiber reinforced by increased adhesion between cement paste and steel fiber. And so, in this paper, we dealt SFRC for the purpose of efficiently using of industrial by-products and its economical manufacturing. Also we performed the test for durability such as chemical resistance, freeze-thaw resistance and accelerated carbonation of SFRC using fly ash.