排煙脫黃石膏로부터 無水石膏 製造 및 適用 特性

현종영,정수복,채영배,김병수,Hyun, Jong-Yeong,Jeong, Soo-Bok,Chae, Young-Bae,Kim, Byung-Su 한국자원리싸이클링학회 2005 資源 리싸이클링 Vol.14 No.2

화력발전소의 배연탈황공정에서 발생된 탈황석고의 용도확대 및 천연 무수석고의 대체 가능성을 조사하기 위하여 탈황석고로부터 건식 열처리법에 의한 무수석고의 제조특성 및 탈황 무수석고에 대하여 시멘트 및 콘크리트 2차 제품으로의 적용 특성을 조사하였다. 탈황석고로부터 Ⅱ형 무수석고의 상전이는 700$^{\circ}C$ 부근에서 완전히 종료되었고, 이러한 Ⅱ형 무수석고의 상전이 과정에서 입자크기의 변화 등을 확인할 수 있었다. 천연 무수석고와 탈황 이수석고로부터 제조된 무수석고는 화학성분 조성, 입자크기, 열적특성 등의 물성이 유사하였다. 무수석고를 시멘트나 콘크리트 2차 제품에 적용시킬 때 부식문제를 발생시킬 수 있는 황산기(SO$_4^{2-}$)의 용출실험 결과, 700$^{\circ}C$에서 1시간 열처리로 제조된 탈황 무수석고는 천연 무수석고에 비하여 황산기의 용출량이 약 50 wt.% 감소됨을 확인할 수 있었고, 소석회(Ca(OH)$_2$) 3 wt.%의 첨가에 의해 황산기의 용출량이 천연 무수석고에 비하여 약 70 wt.% 감소시킬 수 있었다. 탈황 무수석고를 시멘트 및 콘크리트 2차 제품에 적용시킨 결과, 압축강도 등의 물성이 천연무수석고에 비하여 동등 또는 우수함을 확인할 수 있었다. The manufacture property of anhydrous calcium sulfate (anhydrite Ⅱ) from flue gas desulfurization (FGD) gypsum discharged from domestic thermoelectric power plants to apply as an auxiliary material of cement and concrete by high temperature treatment were investigated. The FGD gypsum was completely converted to anhydrite Ⅱ at the temperature of 700$^{\circ}C$ and the retention time of 1 hr. In the phase transformation process, particle size was also changed. The chemical composition, particle size and heat property of anhydrite Ⅱ made from the FGD gypsum were similar to them of natural gypsum. In the leaching test of sulfate ion (SO$_4^{2-}$) at the temperature of 90$^{\circ}C$ and the retention time of 1 hr, the amount of leached SO$_4^{2-}$ for the anhydrite Ⅱ that was sintered at 700$^{\circ}C$ for 1 hr was about 50 wt.% based on that of natural gypsum. In addition, the amount of leached SO$_4^{2-}$ for the anhydrite Ⅱ by adding the slaked lime of 3 wt.% decreased about 70 wt.% comparing with that of natural gypsum. In the application test, the compressive strength of cement and concrete manufactured by using the anhydrite Ⅱ as an auxiliary material were similar or superior compared with them of cement and concrete done by natural gypsum as an auxiliary material.

무수석고 함량이 고로슬래그 미분말을 대량 활용한 콘크리트 특성에 미치는 영향

문규돈(Moon, Gyu-Don),김주형(Kim, Joo-Hyung),조영근(Cho, Young-Keun),최영철(Choi, Young-Cheol) 한국건설순환자원학회 2014 한국건설순환자원학회 논문집 Vol.2 No.3

온실가스 저감 및 자원활용 목적으로 고로슬래그 미분말을 다량으로 활용한 콘크리트에 대한 연구가 활발히 진행되고 있으나, 조기강도 및 내구성능 확보에 어려움이 있다. 따라서, 본 연구에서는 무수석고 함량(0%, 4%, 6%, 8%, 10%)에 따라 고로슬래그 미분말을 대량 활용한 콘크리트의 수화, 강도발현, 크리프, 탄산화, 건조수축 특성을 분석하였다. 무수석고를 바인더의 4~6% 수준으로 치환할 경우 고로슬래그 미분말 대량 활용 콘크리트의 가장 취약점인 초기강도 발현을 보완할 수 있으며, 내구성 측면에서도 보통 포틀랜드 시멘트를 사용한 콘크리트와 유사한 성능을 발현하는 것을 알 수 있었다. 반면, 무수석고를 8% 이상 활용할 경우 초기강도 증진 효과가 미흡한 결과를 나타냈다. High volume slag concrete is attracting new attention and are thought to have promising potential for industrial applications, partly due to the climate debate, but especially due to their very low heat of hydration and their good durability in chemically aggressive environments. However, High volume slag concretes tend to have slower strength development especially. In this study, the effect of anhydrite () on the mechanical and durability performance of high volume slag concrete were investigated. The main variables were anhydrite contents (0, 4, 6, 8, 10%). Test results show that 4~8% anhydrite concrete have improved engineering properties (hydration, compressive strength, shrinkage, creep, carbonation) as control concrete at early ages.

무수석고와 C₁₂A₇계 슬래그를 사용한 수축저감제 및 모르타르 특성

박수현,추용식,서성관,박재완,Park, Soo-Hyun,Chu, Yong-Sik,Seo, Sung-Kwan,Park, Jae-Wan 한국건설순환자원학회 2013 한국건설순환자원학회 논문집 Vol.1 No.2

In this study, shrinkage reducing agent was fabricated with $12CaO{\cdot}7Al_2O_3(C_{12}A_7)$ of CA-based slag and anhydrite. Mortars added shrinkage reducing agent were experimented for enhancement of shrinkage reduction and compressive strength. The properties of setting time, length change and compressive strength of mortar changed with mixing ratios. From 0% to 6% $C_{12}A_7$-based slag, setting times got shorter and length changes of mortars were similar to 7days. From 1day to 7days, the more mortar had $C_{12}A_7$-based slag, the higher compressive strength. At 28days, compressive strength of mortars with 6% $C_{12}A_7$-based slag was about 36MPa. After 35days, mortar with 6% $C_{12}A_7$-based slag had the lowest ratio of shrinkage reduction. So mortar with 6% $C_{12}A_7$-based slag had the excellent characteristics such as compressive strength and shrinkage reduction ratio. 본 연구에서는 CA계 슬래그와 무수석고를 사용하여 수축저감제를 제조하였으며, 모르타르의 압축강도와 건조수축 특성을 향상시키기 위해서 상기 수축저감제를 첨가하였다. 모르타르의 응결시간, 길이변화율 및 압축강도는 수축저감제의 배합비율에 따라 변화하였다. 슬래그가 0~7%까지 첨가된 모르타르는 슬래그 첨가량 증가에 따라 응결시간이 짧아졌으며, 7일까지의 길이변화율은 유사하였다. 7일 양생조건의 압축강도는 $C_{12}A_7$계 슬래그 첨가량 증가에 따라 증가되었다. $C_{12}A_7$계 슬래그가 6% 첨가된 모르타르의 28일 강도는 약 36 MPa이었으며, 35일에서의 건조수축율은 가장 낮은 값을 나타내었다. 그러므로 $C_{12}A_7$계 슬래그가 6% 첨가된 모르타르에서 우수한 물리적 특성을 발현하는 것으로 판단할 수 있었다.

삼성분계 혼합시멘트 모르타르의 조기강도 향상을 위한 실험적 연구

배준영 ( Jun Young Bae ),장영일 ( Young Il Jang ) 한국복합재료학회 2012 Composites research Vol.25 No.4

최근 대규모 토목구조물의 내구성 향상 및 수화열 저감 성능을 확보하기 위하여 1종 보통포틀랜드시멘트에 고로슬래그미 분말 및 플라이애시를 혼합 치환한 삼성분계 혼합시멘트(TBC)의 개발 및 현장적용이 증가하고 있다. 또한 최근 건설사를 중심으로 공사비용 절감 등을 이유로 공사기간 단축 노력이 계속되고 있다. 이를 위해 콘크리트의 조기강도 성능이 요구되어진다. 따라서 상대적으로 조기강도 발현이 느린 TBC의 성능 보완이 필요하다. 이 연구에서는 TBC 모르타르의 조기강도 발현 성능을 향상시키기 위한 노력으로, 고로슬래그미분말 및 무수석고의 분말도와 첨가율을 조절하여 모르타르의 압축강도, SO3 함량 및 SEM 분석을 실시하였다. 실험 결과, TBC 모르타르는 분말도 약 4,200 cm2/g의 고로슬래그미분말을 사용하고 분말도 약 10,000 cm2/g 의 무수석고 3.5%를 첨가하고 SO3함량을 3.72% 내외로 관리하는 것이 가장 우수한 조기강도 특성을 보이는 것으로 나타났다. Recently, the development and field applications of Ternary Blended Cement(TBC), where blast furnace slag and fly ash are recycled in Ordinary Portland Cement(OPC) in order to obtain improvements in the durability and heat of hydration reduction performance in large scale civil structures, have been increasing. Also, there are continuing efforts by construction companies to reduce the construction time with the aim of reducing construction costs. Therefore, there is a need to improve the performance of TBC, which has a relatively slow early strength development. In order to improve the early strength of TBC mortar, the compressive strength, SO3 content, and SEM analysis was determined in this study on mortar with the fineness and content of blast furnace slag and anhydrite regulated. As a result, to secure the early strength of TBC mortar, using blast furnace slag with a fineness of approximately 4,200 cm2/g, adding 3.5% anhydrite with a fineness of approximately 10,000 cm2/g, and managing the SO3 content to roughly 3.72% was found to provide the most outstanding early strength properties.

무수석고를 활용한 비소성 시멘트모르타르의 내화학성에 관한 연구

한동엽,이재규,김지훈,형원길 대한건축학회지회연합회 2012 대한건축학회지회연합회 학술발표대회논문집 Vol.2012 No.1

고로슬래그미분말 및 무수석고를 활용한 PHC말뚝 콘크리트용 혼화재 개발

한천구(Han Cheon-Goo),김종백(Kim Jong-Baek) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.8

This study investigated the possibility of high performance admixture for Pretensioned spun high strength concrete pile(PHC) to mix blast furnace slag and anhydrite with several fineness and replace contents. The results were following. The results for compressive strength, workability and economical efficiency was profitable when 40 %/C blast furnace slag with 8000 ㎠/g and 1.14~11.66 % of anhydrite was used. For the hydrate properties using blast furnace slag and anhydrite mixture, the strength revelation was high caused by latent hydraulicity reaction and filling up effect as XRD and thermal analysis. when the anhydrite used heavy, the strength was decline because of expansion by too much ettringite generation. The blast furnace slag with 8000 ㎠/g and anhydrite mixture could be used as mineral admixture for PHC using autoclave curing method, and it was effective at standard curing method. For these results, it could be a high performance admixture for high durability and flowability concrete.

고로슬래그와 무수석고가 숏크리트의 강도에 미치는 영향

유성희(Sung Hee Ryu),신경준(Kyung-Joon Shin),김윤용(Yun-Yong Kim) 한국콘크리트학회 2012 콘크리트학회논문집 Vol.24 No.1

고로슬래그미분말 및 무수석고를 활용한 PHC말뚝 콘크리트용 혼화재 개발

한천구,김종백,Han, Cheon-Goo,Kim, Jong-Baek 대한건축학회 2011 대한건축학회논문집 Vol.27 No.8

This study investigated the possibility of high performance admixture for Pretensioned spun high strength concrete pile(PHC) to mix blast furnace slag and anhydrite with several fineness and replace contents. The results were following. The results for compressive strength, workability and economical efficiency was profitable when 40 %/C blast furnace slag with 8000 $cm^2/g$ and 1.14~11.66 % of anhydrite was used. For the hydrate properties using blast furnace slag and anhydrite mixture, the strength revelation was high caused by latent hydraulicity reaction and filling up effect as XRD and thermal analysis. when the anhydrite used heavy, the strength was decline because of expansion by too much ettringite generation. The blast furnace slag with 8000 $cm^2/g$ and anhydrite mixture could be used as mineral admixture for PHC using autoclave curing method, and it was effective at standard curing method. For these results, it could be a high performance admixture for high durability and flowability concrete.

C12A7계 바인더와 무수석고를 혼입한 모르타르의 염화물 확산 및 압축강도 특성

노병철,윤용식 한국건설순환자원학회 2022 한국건설순환자원학회 논문집 Vol.10 No.4

In this study, as the preliminary research on the development of heating concrete members, compressive strength and accelerated chloride diffusion behavior in the mortar specimens containing C12A7 based binder and anhydrite was evaluated. Also, the effect of the mixing ratio of the citric acid based retarder was quantitatively evaluated by considering 4 levels of mixing cases. The compressive strength tests of the mortar specimen were performed referred to KS L ISO 679, and the accelerated chloride diffusion tests were performed according to NT BUILD 492 and ASTM C 1202. In the mortar with 0.3 % of retarder, the highest compressive strength was evaluated, which showed the strength development ratio of 127.6 % compared to the control case. It was considered that engineering performance was improved by effectively securing setting and curing t ime with 0 .3 % o f citric a cid based retarder. As t he r esul t of t he e valuation o f the passed c harge and the accelerated chloride diffusion coefficient, the evaluation results had similar behavior with the results of compressive strength. According to the previous study, the strength behavior and the chloride diffusion behavior had a linear relationship. The mixture showing the highest strength performance had the highest durability performance for chloride ingress, and the heating concrete development from this study will be performed in the future.

천연 수경성 석회의 수화특성에 미치는 석고의 영향

문기연,최문관,조계홍,조진상,안지환,홍창우,Moon, Ki-Yeon,Choi, Moon-Kwan,Cho, Kye-Hong,Cho, Jin-Sang,Ahn, Ji-Whan,Hong, Chang-Woo 한국자원리싸이클링학회 2015 資源 리싸이클링 Vol.24 No.1

본 연구에서는 고로 수쇄 슬래그 및 석고를 혼합한 3성분계 천연 수경성 석회 페이스트에서 석고종류 및 혼합량에 따른 수화특성 변화를 확인하고자 하였다. 고로 수쇄 슬래그 20 %를 혼합한 천연 수경성 석회에 무수석고, 반수석고, 이수석고를 각각 3 %, 10%를 혼합하여 석고의 용해도 및 반응성에 따라 수화초기 생성되는 수화물의 종류와 생성량을 분석하였으며, 이에 따른 물리적 특성 변화거동에 대하여 조사하였다. 페이스트를 활용한 수화특성 결과 모든 샘플에서 수화초기 ettringite, C-S-H와 같은 수화물이 생성되었으며, 재령이 길어짐에 따라 수화물의 생성량이 증가하였다. 압축강도 측정결과, 석고 혼합량이 3 %일 때 더 높은 강도를 보였으며 재령 28일에서 무수석고 및 반수석고가 이수석고를 혼입할 경우 보다 높은 특성을 나타내었다. In this study, change of hydration property with contents and type of gypsum in ternary natural hydraulic lime containing blast furnace slag and gypsum was investigated. Anhydrite, hemihydrate and dihydrate were added 3 % and 10 %, respectively in natural hydraulic lime adding blast furnace slag 20 %. Hydration and physical behavior due to solubility and reactivity of different types of gypsum were analyzed in early hydration. As a result of analysis of hydration properties, in all samples, hydrates such as ettringite and C-S-H were produced in early hydration, and amount of hydrates with increase of hydration time was increased. In the case of compressive strength, when contents of gypsum are 3 %, it was higher compressive strength than other specimens. At hydration 28 days, for addition of anhydrite and hemihydrate, compressive strength was more than adding dihydrate.