• 제목/요약/키워드: Activators

검색결과 345건 처리시간 0.03초

초기 고강도 고로슬래그 시멘트의 개발 (Development of High Strength Blast Furnace Slag Cement at Early Ages.)

  • 황인태;김태식;박응모;소승영;소양섭
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
    • /
    • pp.823-828
    • /
    • 1999
  • Blast furnace slag cement(BSC) has many merits in relation to its prodution cost or environmental problem of these days, but it has still some limitation in broad use mainly because it has the lower early hydration strength than the normal portland cement(PC) has. In the present study, several different experimental concepts to improve its low strength in the early hydration stage were tried out which addition of the effective alkali activators such as Ca(OH)2 and limestone powder, fly ash in existing BSC. It was found that the addition of suitable quantity the effective alkali activators such as Ca(OH)2 and limestone powder, fly ash in BSC can be a possible way to get enough early strength compared with the PC and existing BSC.

  • PDF

폐석고 및 폐석회를 자극제로 이용한 비소성 시멘트의 수화반응 (Hydration Reaction of Non-Sintering Cement using Waste Gypsum and Waste Lime with Activators)

  • 문경주;소양섭
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
    • /
    • pp.232-235
    • /
    • 2004
  • This study aims to manufacture non-sintering cement(NSC) by adding phosphogypsum(PG) and waste lime(WL) to granulated blast furnace slag(GBFS) as sulfate and alkali activators. This study also investigates the basic physical properties and hydration reaction of NSC, and evaluates its reusing possibility as construction material. Results obtained from this study have shown that GBFS was affected by $So_4^{2-}$ in waste PG and stimuli under wet condition, left slag components, created Ettringite and CSH gels, and eventually started being hydrated. These hydrated creations formed dense structures like CSH based on Ettringite and contributed in allowing the mortar to reveal high strength.

  • PDF

고로슬래그 시멘트의 초기강도 발현에 있어서 수산화칼슘의 영향 (An Effect of $Ca(OH)_2$ on Development of an Early Age Strength of GGBFS Cement)

  • 이제방;김재신;소승영;소양섭
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
    • /
    • pp.64-69
    • /
    • 1999
  • Slags are by-products of the metallurgical industry. The most important slag from the standpoint of the quantity used as building material is iron blastfurnace slag. Slags are either crystalline stable solid used as aggregates or glassy material used as hydraulic binder. Slag cements are low heat of hydration cements. Slags react more slowly with than portland cement but they can be activated chemically. Activatiors can be either alkaline activators such as soda, lime, sodium carbonate, sodium silicate or sulphate activators such as calcium sulphate or phosphogypsum. So, in this study slaked lime was used as an activator that the compressive strength of this modified cement(M1 type) is high range in early age. And initial setting time of M1 type cement was shorter than conventional cements.

  • PDF

아크방전에 의해 표면개질 된 고로슬래그를 사용한 시멘트 경화체의 수화 특성 (Hydration Properties of Cement Matrix using Surface Treatment Blast Furnace Slag by Arc Discharge)

  • 김선아;김현성;박선규
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2018년도 춘계 학술논문 발표대회
    • /
    • pp.91-92
    • /
    • 2018
  • A glassy thin film was formed on the surface of the blast furnace slag. When blast furnace slag is used as an admixture of concrete, addition of alkali activators were required. However, alkali activators are not only dangerous as chemical products, but they are also difficult to use as expensive materials. Therefore, it is necessary to study the way of removal of the glassy thin film of blast furnace slag without the risk and cost increase. In this study, to solve this problem, experiment was carried out to improve the hydration reactivity by treatment the surface of blast furnace slag using arc discharge. Experimental results show that when the surface of the blast furnace slag was tratmented by arc discharge, the glassy thin film was destroyed. And the hydration reactivity was improved, the compressive strength was increased.

  • PDF

Energy Transfer between Activators at Different Crystallographic Sites

  • Sohn, Kee-Sun;Lee, Sang-Jun;Lee, Bong-Hyun;Xie, Rong-Jun
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
    • /
    • pp.239-242
    • /
    • 2009
  • $Sr_2Si_5N_8:Eu^{2+}$, one of the most recently developed phosphors for use in white light emitting diodes, exhibits a two-peak emission. Namely, the emission band of $Sr_2Si_5N_8:Eu^{2+}$ is deconvoluted into two Gaussian peaks irrespective of the $Eu^{2+}$ concentration. We examined the two-peak emission of $Sr_2Si_5N_8:Eu^{2+}$ by analyzing the time-resolved photoluminescence spectra. We revealed that the two-peak emission was closely associated with the energy transfer taking place between $Eu^{2+}$ activators located at two different crystallographic sites in the $Sr_2Si_5N_8$ structure. The experimental results coincided well with the rate equation model involving the crystallographic information of the host.

  • PDF

Locus Control Region의 구조와 기능 (The Structure and Function of Locus Control Region)

  • 김애리
    • 생명과학회지
    • /
    • 제17권11호
    • /
    • pp.1587-1592
    • /
    • 2007
  • Locus control region (LCR) is a cia-acting element which regulates the transcription of genes in developmental stage and/or tissue-specific pattern. Typically, LCR consists of several DNase I hypersensitive sites (HSs), where the binding motifs for transcriptional activators are present. The binding of activators to the HSs recruits chromatin modifying complexes to the LCR, opening chromatin structure and modifying histones covalently through the locus. LCR forms close physical contact with target gene located at a distance by looping away intervening region. In addition, non-coding RNA is transcribed from LCR toward target genes in continuously acetylated active domain. These structural and functional features of LCR suggest that the LCR plays many roles in chromatin activation and transcriptional regulation.

산업부산물과 알칼리 활성제를 사용한 콘크리트의 물리적 특성에 관한 연구 (A Study on the Physical Property of concrete using Industrial by-product and Alkali Activators)

  • 이선관;김영수
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2013년도 추계 학술논문 발표대회
    • /
    • pp.54-55
    • /
    • 2013
  • Recently, The economic growth has increased carbon dioxide emissions. so, It is caused by social problem to environmental damage and human health due to global warming. Accordingly, The method solution is to the amount of cement and to use industrial by-product such as Blast furnace slag, Fly Ash, and Red-mud. Thus, The purpose of this study is to analyze the physical property of concrete with red-mud. So, this study carries out the basic performance test of concrete such as, air content, slump, and compressive strength. In this work test is conducted according to sequence of materials using concrete twin mixer.

  • PDF

무기 ELD용 ZnS:Mn,Cu,Cl 형광체의 광학적 특성 연구 (Optical Properties of ZnS:Mn,Cu,Cl Phosphor for Inorganic ELD)

  • 이학수;곽지혜;한상도;한치환;김정덕
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
    • /
    • pp.424-425
    • /
    • 2006
  • Zinc sulfide is a well-known host material of phosphor emitting different radiations dependent on different doping impurities of metallic ion. It emits green, blue, orange-yellow or white colors by doping with activators such as copper, silver, manganese and so on. In this study, manganese, copper and chlorine doped ZnS phosphor (ZnS:Mn,Cu,Cl) was synthesized by solid-state reaction method. The optical properties were investigated according to different concentrations of sulfur and activators used during the synthesis process.

  • PDF