• 건축역사연구
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• 제25권3호
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• pp.37-45
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• 2016

This study was to investigate the firing method of limestone in Joseon Dynasty, and analyze the physical chemical properties of lime mortars in Joseon Dynasty. This study was to manufacture and evaluate the firing experiment and mortar of Limestone by each sort in order to reproduce the traditional lime mortars in Joseon Dynasty, and investigate the behavior to improve physical properties according to the firing method of Limestone. This study has found out that there were screening criteria and standard of appropriate firing temperature about the Limestone in Joseon Dynasty. Accordingly, this study was to improve its strength through various additives and mixture. In particular, in case of Limestone, the black and blue Limestone were preferred, and most of domestic Limestones were low grade Limestone including the clay and took ivory white or blue with low whiteness. This study has shown that the low grade Limestone was mined by the surface mining compared with the high grade Limestone as underground mining method, and could be used because it was easy to mine relatively and there was possibility that Natural Hydraulic Lime(NHL) was used with the traditional lime mortars in Joseon Dynasty.

• 보존과학회지
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• 제34권4호
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• pp.295-303
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• 2018

The application of reinforcing agents with hydraulic property and strength development characteristics was studied under conditions similar to those of mural-painting mortar made with oyster shell powder. Reinforcement mortar made with oyster shell powder showed hydraulic properties and strength to supplement the weaknesses of natural hydraulic lime(NHL); this confirmed its possibility as a wall-reinforcing material with enough strength for preserving mural paintings. Reinforcement mortar 1 showed hydraulic property and general characteristics of lime mortar, such as consistency and viscosity, as well as lower strength and higher whiteness compared to an NHL product. For Reinforcement mortar 2, the original wall sample characteristics were reflected by mixing more shell produced through calcination; and it showed similar strength to that of Reinforcement mortar 1 as well as high whiteness. In measuring the contraction ratio of reinforcement mortar samples, Reinforcement mortar 1 and 2 showed more stability in property change compared to the NHL Group.

• 자원리싸이클링
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• 제24권1호
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• pp.12-20
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• 2015

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.

• 한국세라믹학회지
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• 제51권2호
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• pp.72-81
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• 2014

The main mineral phases of natural hydraulic lime (NHL) as a hydraulic lime binderare $Ca(OH)_2$, $C_2S$, $C_3S$, $C_3A$, and $SiO_2$ residues. Also, NHL has the characteristic of setting and hardening by a hydration reaction with water and by carbonation reactions with carbon dioxide from the air. In this study, in an effort to investigate changes of the mineral phases by NHL hydration and carbonation reactions, transitions of mineral phases and the microstructures of hardened pastes were analyzed by XRD, DSC, SEM, and by pore size distributions using domestic and foreign-sourced NHL pastes after curing at 1, 3, 7, and 28 days. On the basis of the analysis results, it was confirmed that domestic low-grade limestone can be used for the manufacturing of NHL. The main hydration mineral phases were $Ca(OH)_2$, $CaCO_3$, $C_2S$, and $SiO_2$ residues, while in the case of foreign-sourced NHL, a small amount of an aluminium hydration phase formed. Also, the $CaCO_3$ content after the carbonation reaction increased with an increase in the curing time. After hydration for 28 days, NHL containing considerable amounts of $C_2S$ and $C_3S$ showed higher carbonation ratios than others types.

• 한국세라믹학회지
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• 제53권2호
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• pp.206-214
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• 2016

This study aims to produce dolomitic hydraulic lime (D-NHL) using domestic low grade dolomitic limestone and to determine the effect of adding blast furnace slag (BFS) and gypsum as part of an investigation of the hydration properties of D-NHL to increase the mechanical properties. The main mineral phases of D-NHL as a hydraulic lime binder were $Ca(OH)_2$, $Mg(OH)_2$, $C_2S$, $C_3S$, and MgO residues. $Ca(OH)_2$ transformed into $CaCO_3$ in D-NHL paste over the period of 28 days, but the carbonation of $Mg(OH)_2$ and the hydration of $C_2S$ did not occur until hydration, after 28 days. Through an investigation of the hydration properties of D-NHL pastes mixed with BFS and gypsum, Al-based compounds such as calcium aluminate hydrates ($C_4AH_{13}$) and ettringite were observed at early hydration time. The compressive strength was improved due to the increased quantities of these hydration products. These results show that good performance results from the application of dolomitic hydraulic lime and that a high value product can be made from domestic waste materials.

• 한국농공학회지
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• 제43권2호
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• pp.122-131
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• 2001

When mixed with lime, sand-bentonite mixture is characterized by considerable hydraulic properties similar to natural pozzolans and may therefore be increased in the strength of sand-bentonite mixture. The present study reports that results obtained in a series of laboratory tests carried out using particular mixing ratio of lime-sand-bentonite with the aim of investigating physical characteristics, permeability and strength. The results were compared and analyzed according to hydration time and lime content. Test results showed that increasing of strength and decreasing of permeability by proper lime content. Curing for longer periods increased unconfined compressive strength of mixture. Based on results of the falling head permeability test, mixtures of lime content 3%, 6% and 9% were satisfied in using as liner after 8-day curing periods.

• 한국세라믹학회지
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• 제51권2호
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• pp.88-96
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• 2014

Natural hydraulic lime (NHL) is produced by burning a form of low-grade limestone containing silica and alumina which, above certain temperatures, combine with calcium oxide. The resulting silicates and aluminates impart hydraulic properties to the product. This study aims to determine the calcined characteristics of NHL using domestic low-grade limestone with maximized hydraulic properties. Six types of low-grade limestone containing $SiO_2$ were selected and experiments were carried out with different burning temperatures and holding times. The burning temperature and holding time as the most suitable burning conditions were $1,200^{\circ}C$ to $1,300^{\circ}C$ and 3 to 7 h, respectively, for the manufacturing of NHL from domestic low-grade limestone. These results demonstrate the feasibility of NHL using domestic low-grade limestone to produce NHL.

• 박물관보존과학
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• 제21권
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• pp.29-40
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• 2019

고분벽화 벽체 보강제로써 천연 수경성 석회의 적용 가능성을 확인하고자 실험연구를 실시하고 그 결과를 제시하였다. 선행된 고구려 고분벽화 관련 연구를 통해 벽체 의사시료와 NHL 제품을 활용한 조건별 보강제 시료를 제작하였다. 시료는 고분 내부 환경을 고려한 고습 조건에서 7일, 28일, 84일간 양생하였으며, 기간별 치수안정성 및 강도 등 물성평가를 수행하였다. 실험 결과, NHL 제품은 경화속도가 빠르고 수축률이 적어 보강제로써의 적합성은 확인되었으나 벽체 물성대비 강도 차이가 크고 백색도가 떨어지는 등의 단점이 확인되었다. 치수안정성 및 압축강도 평가 결과 NHL 제품과 고분벽화 벽체 의사시편을 혼합한 조건이 상대적으로 벽체 보강제로써 적합한 값을 지닌 것으로 나타났다. 따라서 손상된 고분벽화 벽체 보강제로 천연 수경성 석회를 적용하기 위해서는 대상 벽체의 조건에 따라 적합한 경화시간 및 강도를 발현할 수 있는 조건이 고려되어야 할 것으로 판단된다.

• 자원리싸이클링
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• 제26권1호
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• pp.43-50
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• 2017

본 연구에서는 무기질 첨가재를 혼합한 천연수경성석회의 초기경화 거동분석을 위해 multiple light scattering 분석법을 이용하였다. 자체 제조한 천연수경성석회의 물성향상을 위해 고로수쇄슬래그 및 3종류의 석고를 혼합비에 따라 혼합하였으며 물-고체비 0.6으로 페이스트를 제조하였다. 제조한 페이스트를 이용하여 원통형의 용기에 일정량을 담아 장비(Turbiscan LAB, Formulaction)에 장입하여 분석을 실시하였다. 페이스트로부터의 backscattering flux(BS, %)는 $23^{\circ}C$의 온도에서 분석용기 전체높이(55 mm)에 대해 24시간 동안 10분 간격으로 측정되었다. 모든 시료에서 전체적으로 BS는 시간경과에 따라서 증가하는 경향성을 보였다. 고로수쇄슬래그와 석고를 첨가함에 따라서 시간에 따른 BS의 증가 속도는 0.02에서 0.38 BS %/hour 까지 증가하였다. 반수석고를 혼합하였을 경우 가장 높은 backscattering flux와 BS의 증가속도를 보였다.

• 에너지공학
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• 제27권1호
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• pp.59-64
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• 2018

In this paper, we investigated the alternative sources of limestone. Oyster shell waste originated from aquaculture that causes a major disposal landfill problem in coastal sectors in southeast Korea. Their inadequate disposal causes a significant environmental problems araised. Bio mineralization leads to the formation of oyster shells and consists $CaCO_3$ as a major phase with a small amount of organic matter. It is a good alternative material source instead of natural lime stone. The utilization of oyster shell waste for industrial applications instead of natural limestone is major advantage for conservation of natural limestone. The present work describes the limestone and oyster shells hydraulic activity and chemical composition and characteristics are most similar for utilization of oyster shell waste instead of natural limestone.