To provide a construction board having fire prevention and high strength.
A wafer and/or a strand are mutually adhered in the core layer of a board, and furthermore in order to impart fire prevention, hydraulic setting inorganic material of 100-250 pts.wt. for the wafer and/or the strand of 100 pts.wt. is added. In order that the hydraulic setting inorganic material heightens reaction, the material which has the large surface area of Blaine value of 3,000 cm2/g or higher is selected. Since a surface layer secures surface smoothness and obtains a sharp irregular pattern, a mixed raw material mixing cement- based raw material of 30-60 wt.% silicic acid containing substance of 30-60 wt.%, perlite of 0-15 wt.%, flake and/or charcoal of 5-25 wt.% is used.
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