| 摘要 |
PURPOSE:To obtain a retarder of heat generation by hydration capable of suppressing the heat generation by the hydration of cement and preventing the crack of a hardened cement caused by heat generation by mainly using the granular body of alpha-type oxidized starch. CONSTITUTION:The retarder of heat generation by hydration of cement is composed mainly of the granular body of alpha-type oxidized starch. The retarder of heat generation by hydration of cement is dissolved slowly under an alkaline condition in a cement at the time of adding to the cement to use. As a result, after being in contact with water, a retarding material is hardly eluted during an induction period till the start of the hydration reaction of the cement and the elution of the retarding material proceeds in the acceleration period to raise the temp. of the cement by hydration and heat generation. Then, the problem of retarding the time to start the hydration reaction is not generated and in the acceleration period of the hydration reaction, the temp. rises by the heat generation caused by the hydration of the cement. As a result, the elution of the retarding material is increased to intensify the retarding action and the heat generation caused by the hydration is effectively suppressed. |
