• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.648-653
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• 2001

구연산이 첨가된 0.01 M의 $\beta$-인산칼슘 용액을 수열처리 하여 휘스커 상 수산화아파타이트를 합성할 때 수열처리 온도 및 시간이 휘스커의 생성에 미치는 영향을 관찰하였다. 용액을 30$0^{\circ}C$에서 5시간 수열처리 할 때 c축으로 약 60-80$\mu\textrm{m}$까지 성장하고 비교적 순수한 휘스커를 얻을 수 있었으며 이렇게 합성된 수산화아파타이트 휘스커를 수산화아파타이트 시멘트에 1-2 wt% 첨가하였을 때 그 경화체의 직경인장강도는 약 4-6배까지 증가하였다.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.543-548
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• 2008

Solid hydrated by hydro-thermal synthesis reaction is cured two times, the first curing is the steam curing at atmospheric pressure and the second one is a high-pressure steam curing, that is autoclaving. Steam curing is to acquire the proper strength for the resistance of treatment in the first curing process, it was not evaluated properly so far. Because of ignorance about curing, some engineers even think that the dry curing is better than the steam curing. The relation between compressive strength of solid hydrated by hydrothermal synthesis reaction and curing condition are presented in this paper. In order to investigate the effect of curing on the strength properties of specimen, the hydration behavior of solid hydrated by hydro-thermal synthesis reaction has been studied over curing condition using XRD, DT-TGA and porosimeter, SEM analysis technique. The results show that the specimens which are cured with blended method of dry and steam curing appear to have better strength properties than that of dry curing and steam curing. Also, there are significant difference of hydration behavior among curing condition in the solid hydrated by hydro-thermal synthesis reaction.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.122.1-122
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• 2000

• Cement Symposium
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• no.27
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• pp.6-13
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• 2000

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.557-563
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• 2009

This study is on the properties of inorganic porous calcium silicate material made from silica powder through the autoclaving curing, the results of this study should be utilized fundamental data for the development of noise reduction porous solid material using siliceous byproduct generated by various manufacture process. For the manufacture of autoclave curing specimen, various calcareous materials used and siliceous materials used silica powder. In this study, properties in density and compressive strength according to the change of W/B and C/S ratio, microscopy for the shape of pore, SEM and XRD for the examination of hydrate after autoclave curing are carried out respectively. The test results shown that the more slurry density decrease, the more W/B increase at the fresh state, this tendency shown similar to in hardened state. Among the specimens of C/S ratio, the compressive strength of C/S ratio of 0.85 gave the highest the compressive strength. In the results of XRD, tobermorite generated by autoclaving curing was created all of specimens regardless of C/S ratio. To ascertain pore structure, we compared with existing porous calcium silicate product(ALC, organic sound absorbing porous material). The results of microscope observation, pore structure of specimen of this study was similar to that of existing inorganic sound absorbing foam concrete. therefore, we could conformed a possibility of sound absorbing porous solid material on the basis of the results.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.63-70
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• 2009

This study is part of an ongoing research project on the development of a sound-absorbing lightweight foamed concrete manufactured by a hydro-thermal reaction between silica and calcium. As the silica source, pulverized bottom ash was used, and as several cementitious powders of ordinary portland cement, alumina cement and calcium hydroxide were used. Manufacture of foamed concrete was accomplished using the pre-foaming method to make a continuous pore system, which is the method of making the foam by using a foaming agent, then making the slurry by mixing the foam, water, and powders. The experiment factors are W/B, foam agent dilution ratio, and foam ratio, and test items are compressive strength, dry density, void ratio, and absorption rate, as evaluated by NRC. The experiment results showed that the sound absorption of lightweight foamed concrete satisfied NRC requirements for the absorbing materials in most of the experiments. It is thus concluded that foam ratio was the most dominant factor, and significantly affected all properties of lightweight foamed concrete in this study. W/B rarely affected total void ratio and continuous void ratio as well as compressive strength, and dry density and foam agent dilution ratio also had little effect onalmost all properties. The analysis of the correlation between NRC, absorption time, continuous void ratio, and absorption time showed that the interrelationship of the continuous void ratio was high.