LiOH抑制碱-硅酸反应膨胀及其应用研究

研究了沸石化珍珠岩混凝土在KOH，LiOH溶液中压蒸膨胀行为，通过扫描电镜和能量散射谱对产物的形貌和组成进行了分析，说明LiOH抑制碱-硅酸反应膨胀的机理主要是在集料周围形成了含锂盐的非膨胀性产物，含锂产物层的形成对活性集料起保护作用而阻止了碱的进一步侵蚀。研究了由碱-硅酸活性集料和碱-碳酸盐活性集料制成的混凝土在各种碱中的膨胀行为。结果表明：混凝土在相同摩尔浓度的碱中压蒸，在NaOH溶液中膨胀最大，在LiOH溶液中膨胀最小。在应用LiOH抑制碱-硅酸反应膨胀促进碱-碳酸盐反应膨胀的双重作用下，在Spratt细粒硅质灰岩中，少量的白云石在碱环境中可发生去白云石化作用而对膨胀有贡献，也即尽管Spratt灰岩中碱-硅酸反应是主要的，但也存在碱-碳酸盐反应。

LITHIUM HYDROXIDE INHIBITING ALKALI- SILICA REACTION EXPANSION AND ITS APPLICATION

The expansion behavior of concrete microbars with zeolitization perlite autoclaved in KOH, LiOH solution was investigated and the morphology and chemical composition of products were analyzed by scanning electron microscopy and energy dispersive spectra. Results indicate that the mechanism for controlling alkalisilica reaction expansion with LiOH is mainly due to the formation of lithium-containing less-expansive product around aggregate and the protection of the reactive aggregate by the lithium-containing product layer from further attack by alkalis. Expansion behavior of concrete with alkalisilica reactive and alkalicarbonate reactive aggregates autoclaved in different alkalis was studied. The results show that the expansion of concrete microbars is the biggest in NaOH solution and is the smallest in LiOH solution when they are autoclaved in the same molar concentration solution. Under the dual effects of LiOH in inhibiting alkalisilica reaction expansion and inducing alkalicarbonate reaction expansion a small amount of dolomite in the fine-grained siliceous Spratt limestone may dedolomitize in alkaline environment and contribute to the expansion, namely both alkalisilica reaction and alkalicarbonate reaction are existed in Spratt limestone, but alkalisilica reaction is the dominant one.