• 한국세라믹학회지
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• 제55권1호
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• pp.61-66
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• 2018

In this study, fabrication method of inorganic insulation were studied to reduce $CO_2$ from buildings. Main materials for inorganic insulation were used cement, blast furnace slag and aluminum powder as foaming agent. Mixing ratio of cement and slag was controlled and physical properties of inorganic insulation were analyzed. When inorganic insulation was fabricated using cement and slag, expanded slurries were not sunken and hardened normally. Pore size was 0.5 - 2 mm; mean pore size was about 1mm in inorganic insulation. Compressive strength of inorganic insulation increased with curing time and increased slightly with cement fineness. However, specific gravity decreased slightly with curing time; this phenomenon was caused by evaporation of adsorptive water. When inorganic insulation was dried at $60^{\circ}C$, compressive strength was higher than that of undried insulation. The highest compressive strength was found with a mixture of cement (50%) and slag (30%) in inorganic insulation. Compressive strength was 0.32 MPa, thermal conductivity was 0.043 W/mK and specific gravity was $0.12g/cm^3$.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.113-114
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• 2014

Though polymer cement mortar is widely used to repair or reinforce concrete as it has superior adhesion, dense internal structure, chemical resistance, and workability in comparison to those of general cement mortar, studies on its behaviors in high temperature environment such as fire is urgently required. Accordingly, in this experiment, the degrees of reduction in the compressive strength at different temperatures was grasped applying ISO834 Heating Curve, and the effect of polymer content and type on compressive strength could be determined. As a result of this experiment, it is found that polymer type and content have a big effect on reduction of compressive strength in high temperature range, and not only the dynamic characteristics but also the combustion characteristics in high temperature range are required to be studied considering occurrence of a fire in the future.

• Computers and Concrete
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• 제20권6호
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• pp.627-634
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• 2017

Predicting the compressive strength of concrete is important to assess the load-carrying capacity of a structure. However, the use of blended cements to accrue the technical, economic and environmental benefits has increased the complexity of prediction models. Artificial Neural Networks (ANNs) have been used for predicting the compressive strength of ordinary Portland cement concrete, i.e., concrete produced without the addition of supplementary cementing materials. In this study, models to predict the compressive strength of blended cement concrete prepared with a natural pozzolan were developed using regression models and single- and 2-phase learning ANNs. Back-propagation (BP), Levenberg-Marquardt (LM) and Conjugate Gradient Descent (CGD) methods were used for training the ANNs. A 2-phase learning algorithm is proposed for the first time in this study for predictive modeling of the compressive strength of blended cement concrete. The output of these predictive models indicates that the use of a 2-phase learning algorithm will provide better results than the linear regression model or the traditional single-phase ANN models.

• 한국지반환경공학회 논문집
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• 제9권7호
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• pp.37-43
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• 2008

알루미늄 제조 시 발생하는 산업부산물인 Red mud가 첨가된 흙-시멘트 포장 재료를 개발하기 위하여 일축압축강도시험을 수행하였으며 Red mud 함유율, 시멘트 함유율, Fly ash 대체 비율 및 모래의 대체 비율이 일축압축강도에 미치는 영향을 검토하기 위하여 양생기간 7일, 14일 및 21일에 대한 공시체를 제작하였다. 시험결과, Red mud와 Fly ash 함유량이 감소할수록 시멘트 함유량이 증가할수록 일축압축강도는 증가하였고, 화강풍화잔류토를 사용할 경우 모래의 대체 비율에 따른 일축압축강도에 미치는 영향은 없는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.124-129
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• 1995

In this study proposed to rapid and simple methid of test for early evaluation of strength of cement. The obtained results through a series of experiment are summarized as follow. The resistance ratio was decreased as the increase of water-cement ratio. The compressive strength of cement was increased as the resistance ratio increase. The experimental results of compressive strength of cement is shown in the same value no relation with the kind of cement respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.295-296
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• 2023

This study evaluated the compressive strength after making mortar with low cement composition for carbon-neutral steam curing to respond to climate change. Blast furnace slag, fly ash, and ultra-high powder fly ash were used as substitutes for cement. The cement substitute was used at 40% of the mass of cement, and after steam curing, the compressive strength was measured on the 1st, 3rd, 7th and 28th days of age. As a result of the experiment, at the age of 1 day, the mixture using only cement showed the highest strength, but from the 3rd day, the specimen using ultra-high powder showed a high strength development rate, followed by blast furnace slag and fly ash.

• Advances in concrete construction
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• 제5권1호
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• pp.65-74
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• 2017

This study was focused on the use of partial replacement of cement with glass powder in high strength concrete and also copper slag as a partial replacement of coarse sand in concrete. The high strength concrete was prepared with different mineral admixtures like silica fume, fly ash and rice ash husk in different proportions. An experimental investigation has been carried to study about the effect of glass powder on high strength copper slag concrete. The range of glass powder was 10%, 15% and 20% as a replacement of cement. The range of copper slag was 0%, 20%, 40% and 60% as a replacement of natural sand. In addition to the different percentage of fly ash, silica fume, and rice husk ash 5% and 10% was also studied in copper slag concrete. Thus, a total of 51 cubes were casted and compressive strength test was performed on them. The result of the study shows that the value of average compressive strength of concrete after addition of 10%, 15% and 20% of glass powder are 70.47, 72.01 and 73.31 respectively. The value of average compressive strength after addition of 20%, 40% and 60% copper slag as a replacement of sand are 72.18, 74.38 and 73.08 respectively. The value of average compressive strength after addition of 5% and 10% fly ash as a replacement of cement are 71.56 and 73.22. The value of average compressive strength after addition of 5% and 10% silica fume as a replacement of cement are 72.33 and 73.53. The value of average compressive strength after addition of 5% and 10% rice husk ash as a replacement of cement are 72.86 and 69.49. At the level of 20% replacement of cement by glass powder meets maximum strength as compared to that of controlled concrete and copper slag high strength concrete.

• Advances in nano research
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• 제5권2호
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• pp.99-111
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• 2017

Nano particles have been gaining increasing attention and applied in many fields to fabricate new materials with novel functions due to their unique physical and chemical properties. In the present study two nano materials, namely nano silica (NS) and nano clay metakaolin (NMK) were partially replaced with ordinary Portland cement (OPC). The replacement level was varied from 0.5 to 2.0% in OPC and blended in cement mortar with a water cement ratio of 0.40. Mechanical property studies and durability experiments such as compressive strength, tensile strength, water absorption, depth of chloride penetration test. Nano silica was synthesized from rice husk ash and analyze the size using particle size analyzer. The results indicate that the compressive and tensile strength of the cement mortars containing nano materials were higher strength compared to the plain mortar with the same water cement ratio.

• 한국건설순환자원학회논문집
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• 제11권3호
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• pp.218-225
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• 2023

본 연구에서는 염소 성분의 시멘트 수화반응 촉진 효과를 이용하여 염소 함량을 증가시킨 클링커의 조강형 시멘트로서의 활용 가능성을 평가하였다. 실제 시멘트 제조설비를 이용해 염소 성분 200-1,000 ppm 수준의 클링커를 제조하고, 여기에 석고 및 혼합재를 첨가하여 46개의 시멘트 시료를 제조하여 이의 표준주도 및 응결, 압축강도를 측정해 통계 분석하였다. 시험 결과, 염소 함량 증가에 따라 응결이 단축되고, 1일 압축강도가 향상되었지만, 28일 압축강도는 하락하였다. 특히 염소 함량을 230에서 965 ppm으로 증가시킬 경우 1일 압축강도가 4.6 MPa 향상되어 3,400-3,970 cm²/g 범위에서 Blaine을 증가시키는 것보다 향상 효과가 뛰어난 것으로 분석되었다.

• Geomechanics and Engineering
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• 제33권1호
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• pp.19-27
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• 2023

A series of experiments were performed to evaluate the effects of activated carbon on the compressive strength and air content of Portland Cement Concrete (PCC). Activated carbon/PCC composites were prepared by mixing concrete components with commercial activated carbon granules with weight fractions of 0, 0.5%, 1%, and 2% to cement. All PCC specimens were then tested for compressive strength on 7, 14, 21, and 28 days. The experimental results showed that adding 0.5% of activated carbon increased the compressive strength significantly over the curing periods compared to the normal PCC without activated carbon. For the specimens has 0.5% activated carbon, the 7, 14, 21, and 28-day compressive strengths increased by 28.7%, 22.2%, 26.8%, and 22.9%, respectively. However, adding excessive amounts of more than 1% activated carbon had a minimal effect on the compressive strength or even decreased it, which agrees with other studies. Regarding the air contents of the mixtures, adding activated carbon decreased the air content from 3.6% to around 1.5%. The surface morphologies of fine aggregates and activated carbon particles were compared using a novel image processing technique. The results indicated that the surface of activated carbon significantly differs from that of aggregates.