| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a lightweight wood chip cement board which has excellent strength and water resistance. SOLUTION: The wood chip cement board consists of a cement material, wood chips, an inorganic lightweight aggregate, and water, and, at least one side of a base material layer in which the amount of the chips accounts for 5 to 10 wt.% to the total weight is stacked with a surface layer consisting of a cement material, fine wood chips finer than the above chips, an inorganic fine aggregate having a mean grain diameter of <=100μm, and water, and in which the amount of the chips accounts for 5 to 15 wt.% to the total weight, and, a coefficient A defined by the formula (1) is >=3: A=a/bc (1) [wherein, a and b respectively denote the yield stress (MPa) and an elastic modulus (MPa) in a bend test measured in accordance with JIS A1408, and c denotes a dimensional change ratio on drying at 60 deg.C for 48 hr after the saturation of water].</p> |
