3种水质对Ⅳ型石膏固化后膨胀的影响

The effect of pure water and tap-water on the expansion of type Ⅳ gesso after curing

用实验室净水机制备蒸馏水、自来水和市售瓶装纯净水分别调拌的Ⅳ型石膏,固化2、12、24 h后测试线性膨胀率,2组纯净水调拌的Ⅳ型石膏比自来水调拌的Ⅳ型石膏线固化膨胀率小(P<0.05)。自来水中的矿物质成分含量远超过2种纯净水,调拌的Ⅳ型石膏产生了更多的非结晶水,导致较高的线固化膨胀率。

Type IV gesso was cured by laboratory distilled water,tap water and commercially obtained pure water respectively.2 h,12 h and 24 h after curing,linear expansion of the gesso samples was measured and compared.Tap-water curing produced the greatest linear ex-pansion,followed by laboratory distilled water and then pure water（P〈0.05）.The mineral components in the common tap-water may con-tribute to the larger expansion.