长石类矿物析碱对碱-硅酸反应的影响

Alkali Release from Feldspathic Mineral and the Effect in Alkali-silica Reaction

应用热力学方法探讨了298K时钾长石、钠长石、霞石在碱性环境下的碱析出能力,并对这些含碱矿物分解析出的碱对碱-硅酸反应(ASR)的影响进行了讨论。结果表明,由于矿物类型不同,碱性环境下的分解难易程度不同,其中霞石较易分解,钠长石次之,钾长石较难分解;随着溶液pH值增大,除霞石分解能力略有降低外,钠长石、钾长石的分解能力均显著提高。此外,通过加速实验方法证实含有霞石、钠长石、钾长石矿物的集料在使用低碱水泥条件下能显著促进ASR膨胀。

In this article, the dissolution reaction of potash feldspar, albite and nepheline in alkali solution was studied by thermodynamic method, and the capacity of alkali released from feldspathie mineral and the effect to ASR were analyzed also. It was indicated that the capacity of alkali released from nepheline was higher than albite and potash feldspar. With the increasing of OH^- concentration in solution, the dissolution reactions of albite and potash feldspar were strengthen, but the dissolution reaction of Nepheline was weakened slightly. Moreover, it was proved by accelerated test method that aggregate which contains nepheline, Na-feldspar or k-feldspar could considerably enhance ASR expansion, eventhrough using low-alkalieement.