• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.216-217
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• 2017

Slag cement or ternary blended cement is mainly used for non-structural lean concrete for the purpose of foundation work or protection of the waterproof layer on the roof of buildings. However, such non-structural lean concrete has a lot of drying shrinkage cracks, which makes it difficult to maintain the quality of the structure. Therefore, in this study, the compressive strength and the drying shrinkage of ternary blended cement(blended of portland cement, blast furnace slag, fly ash from combined heat and power Plant) for non-structural lean concrete were examined. As a result, it was confirmed that this non-structural lean concrete reduced drying shrinkage compared to the conventional ternary blended cement using fly ash from power plant.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.186-187
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• 2013

Recently, high fluidity concrete is becoming more prevalent. High fluidity concrete uses admixture or thickener in order to prevent separation of materials due to increased fluidity, and, especially, BS is becoming more use for reduced heat of hydration and improved long-term strength. This study examined the effect of BS on fluidity of cement paste from a rheological viewpoint. As for BS types, materials equivalent to 1 types of KS F 2563 and the cement mass was substituted by 20, 40, 60, 80%.

• 한국세라믹학회지
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• 제27권5호
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• pp.589-596
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• 1990

In this study, the freezing and thawing resistance in sea-water of hardened cement paste was investigated by adding slag, diatomaceous earth and fly ash as blending materials and air entraining agent and superplasticizer as admixtures to the cement paste. The structure of hardened cement pate was densified by potential hydraulic properties and pozzolan reactivities of materials and the freezing and thawing resistance of the paste was improved with the effect blending materials and admixtures. As the blending materials were added to the paste, the quantity of C3A was relatively reduced and the formation of expansive ettringite was suppressed to decrease the penetration of sea-water or Cl-, SO42-ion, and then freeze-thaw resistance was enhanced. Particulary, when 40% of slag was mixed, the resistance was excellent.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.119-120
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• 2022

This study investigated the use of different amounts of BFS and POFA. In all mixture systems, 60% cement was replaced with POFA and BFS as a substitute for Ordinary Portland Cement. The results show that with the addition of POFA and BFS, although the early compressive strength will be reduced, the strength will be significantly improved at 28 days. In the ternary system, the 28-day strength is negatively correlated with increasing POFA content.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.161-162
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• 2023

Limestone slag cement is a green and sustainable building material with huge market potential. However, its shortcoming of low early compressive strength needs to be improved. A method of using aluminum sulfate to improve the early strength of ternary mixed mortar was proposed, and its effect and optimal dosage were tested. Macroscopic properties such as mechanical properties and surface electrical resistivity were measured at different dosages (0%, 1%, 2%, 3%). The microstructure and products of the mixtures were tested in detail, including by scanning electron microscopy, thermogravimetric analysis, and X-ray diffraction. The results show aluminum sulfate enhances mechanical properties and significantly increases surface electrical resistivity. The 1% and 2% doses had no adverse effects on the 28-day mechanical properties, while the 3% dose reduced the 28-day strength. Considering the changes in mechanical properties and surface electrical resistivity, 1% aluminum sulfate is the optimal dosage.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6114-6118
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• 2013

본 연구에서는 초음파 탐상시험의 펄스 반사법으로 각각 용접결함에 따른 초음파 펄스파형모형을 연구하였다. 균열은 예리하고 선명한 신호들을 발생한다. 탐촉자를 결함주위로 이동하면 에코높이는 변한다. 긴 균열에서는 탐촉자가 결함 주위를 원형으로 목돌림주사법을 사용하여 탐상하면 에코높이는 급격히 감소한다. 그 에코 봉우리는 바늘과 같이 얇고 날카롭다. 기공은 단일 결함으로부터 발생하는 에코는 예리하고 선명하다 하지만 집단의 기공들은 다수의 반사들이 중첩되고 트레이스가 들쭉날쭉한 에코가 발생한다. 슬래그 개재물은 크랙과 슬래그 결함위치에서 각각 목돌림 주사법을 사용하여 탐상하면 그 에코형상은 어느 정도 차이를 볼 수 있었다. crack은 그 에코높이가 급격히 변하는 반면에 슬래그 개재물은 증가${\rightarrow}$감소${\rightarrow}$증가${\rightarrow}$감소된다. 또한 다수 밀집된 기공의 위치에서 결함은 대표적 에코형상과 같은 잡다한 에코형상은 슬래그에서는 볼 수 없었다. 용입불량은 결함의 에코형상은 크랙과 같이 날카롭고 예리하게 나타났고, crack과 비슷한 에코형상은 갖고 있었다.

• 자원리싸이클링
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• 제7권2호
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• pp.39-45
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• 1998

LD 제강 더스트를 제철원료로 LD 전로 제강 슬래그를 용제로 하고 폐타이어에 의해 제조한 건류탄을 환원제로 사용하여 반사로에서 환원 실험하여 배합비, 온도 및 반응시간 변화에 따른 환원율 및 철 회수율의 영향을 조사하여 다음과 같은 결과를 얻을 수 있었다. 1) $1300^{\circ}C$에서 1시간 동안 환원실험한 결과 탈아연율(removal rate of zinc)이 97%이상이며 잔사중의 Zn은 0.1~0.2%이었다. 2)페렛트 중에 LD 스래그 15~20%, 폐타이어 건류탄 4.1~6.7% 함유된 시료를 대기압, $1350^{\circ}C$에서 3시간동안 환원실험한 결과 선철의 회수율은 89.3~92%이었다. 3)환원제련시에 집진장치에서 회수한 더스튼 Zn 60%의 조산화아연이었다. 4) 회수한 선철의 성분은 Fe 96%, C 1.6%, P 0.08%, S 0.05%이었다. 5) 환원시에 생성한 슬래그의 조성은 $Ca_2Al_2SiO_7$, 8CaO $5SiO_2$ 및 $Na_3Ca_6(PO_4)_5$가 확인되었다.

• 한국도로학회논문집
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• 제15권2호
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• pp.95-103
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• 2013

PURPOSES : To investigate the fundamental characteristics of blast-furnace slag mortar that was hardened with activating chemicals to capture and sequester carbon dioxide. METHODS : Various mix proportions were considered to find an appropriate stregnth development in regards with various dosages of activating chemicals, calcium hydroxides and sodium silicates, and curing conditions, air-dried, wet and underwater conditions. Flow characteristics was investigated and setting time of the mortar was measured. At different ages of 3, 7 and 28days, strength development was investigated for all the mix variables. At each age, samples were analyzed with XRD. RESULTS : The measured flow values showed the mortar lost its flowability as the activating chemicals amount increased in the scale of mole concentration. The setting time of the mortar was relatively shorter than OPC mortar but the initial curing condition was important, such as temperature. The amount of activating chemicals was found not to be critical in the sense of setting time. The strength increased with the increased amount of chemicals. The XRD analysis results showed that portlandite peaks reduced and clacite increased as the age increased. This may mean the $Ca(OH)_2$ keeps absorbing $CO_2$ in the air during curing period. CONCLUSIONS : The carbon capturing and sequestering activated blast-furnace slag mortar showed successful strength gain to be used for road system materials and its carbon absorbing property was verified though XRD analysis.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.43-44
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• 2023

This study evaluated the mechanical and electrical properties of low-cement mortar using a large amount of industrial by-products to reduce carbon emissions from the cement industry. As types of industrial by-products, blast furnace slag and fly ash, which are representative materials, were used, and ultra-high fly ash was mixed and evaluated to solve the problem of initial strength loss. In addition, in order to evaluate the electrical properties, 1% of MWCNT was incorporated relative to the powder mass. As experimental items, the compressive strength was measured on the 1st, 3rd, 7th and 28th days of age, and the rate of change in electrical resistance was measured on the 28th day of age. As a result of the experiment, the initial strength of the test specimen mixed with blast furnace slag and fly ash was significantly lower than that of 100% cement, and the specimen mixed with blast furnace slag showed strength equal to that of cement at 28 days of age. As an electrical characteristic, the electrical resistance was reduced when the load was loaded, and this reason is judged to be the effect of improving the conductivity as the connection between CNTs is narrowed by the compressive load.

• 한국건축시공학회지
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• 제24권1호
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• pp.11-21
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• 2024

본 실험에서는 고로슬래그 미분말 치환율에 따른 이산화탄소 양생 모르타르의 기초 물성을 확인하였다. 실험 결과, 이산화탄소 양생은 CaCO₃의 생성을 촉진하며 공극 감소와 조기 강도 발현에 영향을 준다. Ca(OH)₂가 CaCO₃보다 주된 강도 발현에 영향을 주며 고로슬래그 미분말 치환율이 높은 배합일수록 Ca(OH)₂ 생성이 감소한다. 하지만 Ca(OH)₂가 소모된 이후에도 CaCO₃를 통해 강도가 유지되며 이산화탄소 양생 이후 대기 중에 노출하여도 소요의 성능을 유지할 수 있을 것으로 전망된다. 고로슬래그 미분말 치환율이 50%를 초과할 경우 이산화탄소에 의한 성능 저하를 유발하므로 치환 비율을 조정할 필요가 있다.