| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
In order to make lightweight wood-cement composite board, various parts of micro-Shirasu-balloon were mixed into cement-bonded particleboard. It was expected that the addition of the balloon would not only make them lighter, but also improve some properties. Because the balloon is the burning product from fine pulvernized volcanic glass and possesses very low density, low thermal conductivity, low hygroscopicity, highly melting point, highly heat resistance and incombustibility. Boards for test were made at the mixture ratio under the conditions as follows :
Cement/wood chip ratio(Wood ratio) : 2.0,2.5
Balloon/cement ratio(Balloon ratio) : 0-0.5
Target density : 0.6-1.2 Board size : 350x350x15mm
Results were summarized from physical tests and observation of the boards made as follows :
(1)Target thickness could not be controlled in higher density board of the wood ratio of 2.5 at higher Balloon ratio.
(2)Surface condition of the boards was improved remarkably, especially in lower density boards.
(3)Bending properties and internal bond quality were improved in the boards of the density of 0.8 and more at lower ballon ratio of 0.1 and 0.2. Even the board with the density of 0.8 met the requirements of JIS of High Density Cement-Bonded Particleboard in bending strength. But, those properties decreased in the boards of the balloon ratio less than 0.2.
(4)Thickness swelling after 24h soaking test was reduced remarkably in the boards at the balloon ratio of 0.1 and more, especially in higher density boards.
(5)Five to ten percentile reduction of thermal conductivity was recognized in the boards of the density of 1.2 at the balloon ratio 0.3 and more, and of the density of 1.0 and 0.8 at the balloon ratio 0.2 and more.
(6)All of the boards for test showed high fire resistance and met the requirements of the JIS incombustibility grade 2 of Internal Finish Material.
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