• 한국세라믹학회지
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• 제50권5호
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• pp.341-347
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• 2013

Kaolin-based membranes with a pore size of 0.30-0.40 ${\mu}m$ were successfully prepared by a simple pressing route using low-cost starting materials, kaolin and sodium borate. The prepared green bodies were sintered at different temperatures ranging between 900 and $1200^{\circ}C$. The sintered membranes were characterized by X-ray diffraction, mercury porosimetry, scanning electron microscopy, and capillary flowmetry. It was observed that the porosity decreased with an increase in both the sintering temperature and the sodium borate content, whereas the flexural strength increased with an increase in both the sintering temperature and the sodium borate content. The air flow rate decreased with an increase in the sodium borate content. The typical porosity, flexural strength, and specific flow rate of the kaolin-based membrane sintered with 5 wt% sodium borate at $1100^{\circ}C$ were 37%, 19 MPa, and $1{\times}10^{-3}L/min/cm^2$, respectively, at a p of 30 psi.

• 멤브레인
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• 제9권4호
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• pp.221-229
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• 1999

공칭크기가 0.2${\mu}m인 polytetrfluroethylene(PTFE Satorius사) 정밀여과막에 0.1wt% kaolin benotonite yeast 및 starch 용액을 각각 투과시키고 막을 세척한 후 순수/이소부탄올을 이용한 액체전이법으로 막의 세공분포를 추정하였다 액체전이법으로 추정한 오염되지 않은 PTFE 분리막의 세공분포는 수은침투법 및 전자 현미경 사진의 분포와도 유사하였다 PTFE 막의 세공크기보다 작은 입자가 존재하는 bentonite 및 starch 용액을 투과시킬 경우 분리막 세공이 상당히 오염되어 세공분포가 약 0.3${\mu}m이하로 축소되었다. 그러나 kaolin 용액의 경우에는 0.35${\mu}m 이상의 세공일부만이 부분적으로 오염된 것으로 나타났다 이와같이 액체전이법을 이용한 분리막의 세공분포 측정으로 막오염 현상을 보다 정량적으로 구명할수있었다.

• 콘크리트학회논문집
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• 제11권4호
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• pp.31-41
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• 1999

Blended Low Heat type cement is ground granulated blast furnace slag and fly ash mixed ternary with ordinary portland cement. From the viewpoint of X-ray patterns of domestic LHC, the main components of cement such as $C_2$S, $C_3$A, $C_3$S are considerably reduced. Therefore the heat evolution of LHC paste is 42cal/g lower than of OPC paste. At early age, the compressive strength development of LHC concrete is delayed, but the slump loss ratio of fresh concrete is reduced more than 20% with elapsed time. The penetrability of LHC is lower than that of OPC by 1/7.8 with the penetrability of chloride ion into the concrete until the age of 120 days. And the PD Index value of LHC is 0.44$\times$10-6 $\textrm{cm}^2$/s, which indicates only 39.3% of OPC. From the Mercury Intrusion Porosimetry test of cement past, we know that the pore size of LHC is more dense than that of OPC by production of C-S-H.

• 약학회지
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• 제29권4호
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• pp.176-182
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• 1985

As a part of the studies on adsorptive properties of Korean halloysite clays, Hadong white clays of premium grade were examined for geometric pore structured by mercury porosimetry and for specific surface areas by nitrogen adsorption according to the BET procedure. Three size fractions of the native clay sample were derived from passage BS #100, #200 and #325 meshes, respectively. Several parameters lhus observed in relation to the pore structures are shown below: 1. The size fraction of BS #100, #200 and #325 show internal pore volumes of 25.3, 30.2 and $35.0m^2g^{-1}$, respectively. 2. In the distribution curves of the cumulative pore volume against pore diameter, it has been shown that the larticle sizes, the steeper the distribution over the larger ranges of pore diameters. The converse is true the smaller particles. 3. Internal pore areas increase with decrease in pore sizes. It follows that the pores having diameters of $\leq$0.1$\mu\textrm{m}$ are responsible for more than 90% of the total pore area. 4. The behaviour of nitrogen adsorption can be best described by BET type IV isotherm. Further, the hysteresis loops of the adsorptiondesorption curves become narrower with decresing particle sizes. 5. The specific surface areas observed for the fractions of BS #100, BS #200 and BS #325 are 34.6, 35.4 and 43.2m $^2g^{-1}$, respectively. and the calcined clay of BS #325 has a specific surface area near $30.4m^2g^{-1}$.

• 한국염색가공학회지
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• 제8권5호
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• pp.68-75
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• 1996

Even if fibers are practically identical with respect to chemical composition and denier, the dyeabilities are freqently a little different in an industrial processing. It is difficult to interpret the numerical values of dye diffusion coefficients from a dye solution into fibers. The main reasons are the multicomponent nature of the diffusion process and the inhomogeneities of the substrate, so-called, various kinds of ordered and disordered regions of polymers, void and pores. The equilibrium dye adsorptions and dyeing rates of a disperse dye into the several PET fibers having the same denier were determined at various temperatures. The dyeability of examined samples was divided into two groups, that is, lower dye adsorption fiber and higher ones at the lower temperatures. This result was discussed with the degree of crystallinity, DSC diagram, X-ray diffractometry and Porosimetry of the PET fiber, and an appropriate model for fine structure of PET fiber was proposed.

• Computers and Concrete
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• 제8권4호
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• pp.389-399
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• 2011

The increasing concern for reinforced concrete structure durability has been justifying in many ways in the last few decades. However, there is no perfect durability test method till now. In this research an alternative method, which is based on the cumulative moisture loss percent of the concrete specimens after oven-drying, was proposed to estimate the durability performance of the concrete. Two temperatures were considered for the oven-drying tests: $100^{\circ}C$ and $200^{\circ}C$. Test results showed that oven-drying at $200^{\circ}C$ was obviously an unsuitable procedure to preserve the fragile microstructure of cement-based materials. By contrast, experimental results through oven-drying at $100^{\circ}C$ allowed estimating the moisture loss percent of cement-based materials in a more rational manner. Moreover, the magnitudes of the cumulative moisture loss percent obtained from oven-drying tests at $100^{\circ}C$ for 48 hours have good correlations with the data of other well-known methods, namely, electrical resistance test, water permeability test, and mercury intrusion porosimetry test. This investigation established that regarding the oven-drying test as one of the tests for evaluating the potential durability of concrete is considerably practicable.

• Geomechanics and Engineering
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• 제17권6호
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• pp.543-551
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• 2019

In China, serious environmental problems are induced by the extremely soft construction waste slurries in many urban areas, and there is no appropriate method to treat it presently. In this paper, four model tests were conducted to investigate the efficiency of waste slurry treatment by combining three conditioning agents which can change characteristics of the slurries with a traditional vacuum preloading method. The tests of size analysis of particle aggregate were conducted to investigate the influence of different conditioning agents on the size distributions of particle aggregate. During the model test, the discharged water volumes were monitored. The pore-size distribution and void ratio of the waste slurries after the vacuum preloading were measured by mercury intrusion porosimetry (MIP). It is found that 1) During the natural precipitation, volume of water out of the organic agent is higher than that of the mixed agent, but it is smaller than that of the mixed agent in the vacuum preloading stage; 2) the mixed agent has a higher total volume of water out than the organic agent and the inorganic agent after test, while the organic agent and the inorganic agent have little difference with respect to the drainage effect. The results demonstrate that the combination of mixed conditioning agent and vacuum preloading for the solid-liquid separation in waste slurry has a satisfactory effect and can be applied in engineering practice.

• Geomechanics and Engineering
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• 제18권1호
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• pp.49-58
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• 2019

The effect of microstructure on the permeability of two saturated marine clays was studied through a series of falling head permeability tests and mercury intrusion porosimetry (MIP) tests. The key findings from this experimental study include the following results: (1) The permeability of undisturbed specimens is larger than that of reconstituted specimens at the same void ratio due to different soil fabrics, i.e., the pore size distributions (PSDs), even though they have the similar variation law in the permeability versus void ratio. (2) Different permeabilities of undisturbed and reconstituted specimens at the same void ratio are mainly caused by the difference in void ratio of macro-pores based on the MIP test results. (3) A high relevant relation between $C_k$ ($C_k$ is the permeability change index) and $e*_{10}$, can be found by normalizing the measured data both on undisturbed or reconstituted specimens. Hence, the reference void ratio $e*_{10}$, can be used as a reasonable parameter to identify the effect of soil fabric on the permeability of saturated soft clays.

• Advances in concrete construction
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• 제11권1호
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• pp.11-18
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• 2021

The present study fabricated polyvinyl alcohol (PVA) fiber-reinforced alkali-activated slag/fly ash (AASF) composites with varying mixture ratios of slag and fly ash. The thermomechanical behaviors of the AASF composites exposed to 200, 400, 600, or 800℃ were evaluated by means of compressive strength test, visual observation, and fire resistance tests. X-ray diffractometry, mercury intrusion porosimetry, and thermogravimetry tests were performed to analyze the microstructure change of the AASF composites upon exposure to high temperatures. Specimens exhibited a gradual strength loss up to 600℃, while also showing a significant decrease in the strength above 600℃. The fire resistance test revealed the occurrence of an inflection point as indicated by an increase in the internal temperature at around 200℃. In addition, specimens showed the dehydration of C-S-H gel, the presence of åkermanite, gehlenite, and anorthite upon exposure to 800℃, which is associated with the formation of macropore population with pores having diameters of 1-3 ㎛ and 20-40 ㎛. Visual observation indicated that the PVA fibers mitigated the cracking and/or spalling of the specimens upon exposure to 800℃.

• 공업화학
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• 제22권4호
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• pp.423-428
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• 2011

경북 대포 지역에서 채취한 제올라이트의 시멘트 혼합재료로의 이용 가능성을 검토하기 위하여 제올라이트가 함유된 시멘트의 수화 특성을 연구하였다. 제올라이트가 함유된 시멘트 페이스트에 대하여 수화발열 속도, XRD, EDS, 질소 흡착, 수은 침투 등의 분석을 수행하였다. 제올라이트가 함유된 시멘트 페이스트에서는 제올라이트 양이 증가함에 따라 응결시간이 빨라지고 시멘트의 수화가 촉진되는 경향을 나타내었다. 제올라이트가 함유된 모르터에서는 제올라이트 양이 증가함에 따라 플로우가 크게 감소하였다. 또한 플레인 모르터와 비교하여 단기에 강도증진이 나타났다. 이러한 결과는 시멘트의 수화시 알칼리에 의한 제올라이트의 탈알루미늄 과정에서 제올라이트 입자로부터 이탈한 활성 알루미늄 종과 관련이 있는 것으로 보인다.