コンクリートのセメントペースト部分の粘性について
スポンサーリンク
概要
- 論文の詳細を見る
The viscosity of the cement paste which was one of the factors affecting the plasticity of the fluid concrete was studied. First, the paste made from water and quartz powders, was tested by B-type viscometer with several admixtures or pozzolanes. Then, the cement paste was investigated in the same way as quartz paste. The following results were obtained. 1. The cement paste was more viscous than quartz paste consisted of the same grading as the cement with same amount of water. But, cement and quartz paste kneaded with lime water were nearly of the same viscosity. These results indicate that the causes of higher viscosity of the cement paste than quartz paste are attributed not to its colloidal properties but to pH in the paste. 2. The pastes of the portland cements on the market showed their respective viscosities. And the mount of water required for giving the same viscosities was the smallest in the case of moderate-heat portland cement and the largest for high-early-strength and silica cement. 3. The admixtures reducing the viscosity of the cement paste were AE agents, some sorts of diffusing agents, fly ashes and the fine grains of the aggregates. On the other hand, some admixtures, such as calcium hydroxide, white earth and watight-B (waterproof agent) produced the pastes of high viscosity. But the cement paste containing calcium chloride or blast furnace slag as admixtures showed the same viscosity as plain cement paste. 4. The viscosity of the cement paste was slightly reduced by addition of AE agents, because the air entrained by these agents was just a little. Only pozzolith No. 5 showed the following interesting actions ; the viscosity of cement paste was reduced and the character of paste became dilatancy, if air introduced, by application of it. The viscosity increase was observed otherwise. High viscosity of cement paste in the latter case may be resulted from the viscosity increase of the solution in proportion to the concentration of the solute (pozzolith No. 5) and the adsorption of the solute on the surface of the cement particles. 5. The cement pastes changed their characters from thixotropy into dilatancy by introduction of some sorts of diffusing agents and surface active agents. These results can be applied to the production of the more workable concretes.
- 社団法人日本材料学会の論文
- 1958-01-15