Eigenschaften und Struktur gipsgebundener Spanplatten in Abhängigkeit vom Wasser-Bindemittel-Verhältnis

On gypsum-bonded particleboards, manufactured according to the semi-dry process, the structure of the gypsum matrix and its boundary layers to the particles depending upon the ratio of water/binder (w) were examined by means of scanning electron microscopy. Parallel to that the board strength was tested. The optimum strength was assessed to be at w = 0.4 to 0.5. The gypsum matrix of those boards was characterized by the formation of a homogeneous polycrystal, conformed to the particle surface. For boards with w equal or smaller than 0.3, the gypsum-particle texture was not very compact. At those water/binder ratios the portion of pseudomorphic transitions with corresponding lower strength properties increased.