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Volume 1953 (1953)
- Issue 11 Pages 493-
- Issue 10 Pages 444-
- Issue 9 Pages 399-
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Volume 1953, Issue 11
Displaying 1-8 of 8 articles from this issue
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Shoichiro NAGAI, Michio SEKIYA1953 Volume 1953 Issue 11 Pages 493-498
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (966K) -
Keiichi MURAKAMI, Mitsuo HANADA1953 Volume 1953 Issue 11 Pages 498-503
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSAccording to Langmuir and BET theory, adsorption isotherms of oxygen gas on the gypsum plaster and its hydrated products have been studied to get these surface areas.
The relaxing phenomena of hydrated gypsum have been understood by this experiments. The surface area and compressive and tensile stregth of hydrated gypsum increase by two or three hours after its hydration and then decrease to some lower values. The strength of hydrated gypsum, mixed with acceleator or retader is weaker than the strength of hydrated gypsum with pure water, and surface area of the forwer is less than the latter.
The surface area of CaSO42H2O, α-CaSO4 1/2H2O, β-CaSO4 1/2H2O, α-CaSO4 (sol), β-CaSO4 (sol) and CaSO4 (insol) are studied. The surface area of dehydrated gypsum seems to increase as temperature rises.
The surface area of β-CaSO4 1/2H2O made from, β-CaSO4 (sol) by ageing is nearly aqual to ordinary β-CaSO4 1/2 H2O, but the surface area of CaSO4 (sol) dehydrated from α-CaSO4 1/2H2O does not regain its original area by ageing.View full abstractDownload PDF (892K) -
Takeo Harada1953 Volume 1953 Issue 11 Pages 503-505
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe time for crystallization (waiting time) was measured, when sodium sulfate-and calcium chloride solution were mixed. 40 minutes by adding 40 p. p. m. of Krilium, 2 minntes at no addition.View full abstractDownload PDF (446K) -
Chikara MITSUKI, Masayoshi KITA1953 Volume 1953 Issue 11 Pages 505-509
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESS1. If the lower temperature is keep up sevrsal hours at the beginning of heating procedure, raising the temperature at the later stage does not cause increase of normal consistency of the resultant plaster and is considered to be profitable in respect of promoting reaction in auto-clave.
2. Normal consistency and state of flow of Plaster of Paris does not be affected, so far as rehydration is completed, by dehydration to anhydrite.
3. It is infered from X-ray photograph that there is not essential difference of crystal structure between hemi-hydrates produced by auto-clave and by heating at open atomosphere.View full abstractDownload PDF (1156K) -
Shoichiro NAGAI, Yasushi FUKUMORI1953 Volume 1953 Issue 11 Pages 509-513
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSThe residue obtained from the slaking of quick lime to slaked lime is called “Grappier” and now is not used for any purposes in Japan. The present authors studied on the utilization of this slaked lime residue for making special cements of the desultory or miscellaneous uses as lime-slag or slag-lime cement.
(1) Slaked lime residue (80-50 parts), water granulated blast furnace slag (20-50 parts), calcined gypsum or gypsum plaster (CaSO4.1/2H2O, 0-5 parts) and Portland cement (0-20 parts) were intimately mixed and ground to the special cement as the desultory using cement (Japanese Iudustrial Standard JIS R 5221 (1953)).
(2) Slaked lime residue (10-40 parts), water granulated blast furnace slag (70-40 parts), calcined gypsum or gypsum plaster (CaSO4. 1/2H2O, 20 parts) and Portland cement (0-5 parts) were intimately mixed and ground to the special cement as the lime-slag or slag-lime cement (Japanese Industrial Standard JIS R 5222 (1953)).
(3) The samples about 18 kinds of these prepared special cements were tested on their various physical properties as fineness, time of setting, amount of mixing water, and the bending and compressive strengths of hardened cement-sand (1 : 2) mortars were tested by the method ruled in the Japanese Industrial Standard (JIS R 5201 (1953) : The Testing Method of Physical Properties of Various Cements), and these cements were proved to be useful as the desultory using cement.View full abstractDownload PDF (713K) -
Shuyo ITO, Ichiro TERAOKA, Seiichiro YOSHIHAMA1953 Volume 1953 Issue 11 Pages 513-518
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSIt is well known that the gypsum is used for metal casting as an investment material. In investment casting, wax patterns are used, and therefore dies of gypsum for wax pattern are utilized also. The low temperature metals and alloys such as Alminum, Magnesium, bronz, silmin and others are recently sometimes cast in plaster base investment mold. When gypsum is heated, it undergoes several phase transformation or changes at the dehydration temperatures, and its volume changes gives bad effects on the dimentional preciseness of castings, but when it is misxed with sands such as cristobalite tridymite, silica, and other refractory materials, it shows a suitable thermal expansion, which compensates the volume changes.
We have studied on the investment material that is constructed with the mixture of gypsum and cristobalite, and on the difference between α and β gypsum by the comparison of their volume changes.View full abstractDownload PDF (823K) -
[in Japanese]1953 Volume 1953 Issue 11 Pages 521-523
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (646K) -
[in Japanese]1953 Volume 1953 Issue 11 Pages 523-529
Published: December 30, 1953
Released on J-STAGE: March 07, 2011
JOURNAL FREE ACCESSDownload PDF (1293K)
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