| 摘要 |
PURPOSE:To obtain the titled aggregate free from possibility of significant variation in the porosity even in case of some deviation in the blend ratio, by blending, in specified proportion, large size aggregate and small size aggregate both of which have a specific relationship in terms of their average particle sizes. CONSTITUTION:The objective aggregate can be obtained by blending (A) 20-50wt% of large size aggregate and (B) 80-50wt% of small size aggregate. The average particle size D of the component A and the average particle size d of the component B are related through the inequality: D>20d with the D being pref. 1/10-1/3 times the minimum wall thickness of the molded articles of intention. preferably, 100pts.wt. of the blended aggregate is incorporated with 5-10wt% of fine powder (e.g. calcium carbonate of a size 3-100mu).
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