| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cement composition capable of having shortened curing time to manufacture a product having the same strength as conventional products by specifying the fineness of the cement composition, amount of SO3 , 3CaO.Al2 O3 and 3CaO.SiO2 to promote the curing, in production of splinter wood or wood-wool cement board. SOLUTION: The composition contains powders of 4300 to 8000 cm<2> /g of fineness, 3.5-15 wt.% of SO3 , 8 to 20 wt.%. of 3CaO.Al2 O3 , 40 to 70 wt.% of 3CaO.SiO2 . The strength of the cement is raised rapidly because the surface of the cement is large as the result of having a high fineness, and the cement is capable of easily contacting with water allowing the hydration reaction to proceed rapidly. The initial strength of the cement raises because the content of SO3 is large allowing to increase the amount of sulfate ion in the liquid phase and to promote the production of ettringite. The retarding effect on the hydration of this cement by an organic retarding material is inhibited for the content of 3CaO.SiO2 is high and a plenty of calciumaluminate hydrate is produced in the early stage of the hydration of the cement which absorbs and fixes the organic retarding materials. |
