LiOH对碱-硅酸反应产物膨胀行为的影响

Influence of LiOH on the Expansive Behavior of Alkali-Silica Reaction Product

研究了硅酸与KOH,NaOH以及LiOH反应后所形成产物的吸水能力,结果表明:KOH与硅酸反应后的产物的吸水能力最强,其次是 NaOH,而 LiOH与硅酸反应的产物的吸水能力最弱.通过SEM/EDS对比研究了硅质集料在 LiOH,KOH,LiOH+KOH介质中的膨胀行为,结果表明: LiOH-硅酸反应生成的结构致密的非膨胀性产物硅酸锂L S H包裹在未反应的集料周围,阻止了碱-硅酸反应的继续进行,而 LiOH-硅酸反应过程本身不会引起膨胀;在LiOH存在时,硅酸与KOH反应后形成的 K S H中的 K+被Li+取代生成L S H,而L S H阻碍了碱-硅酸反应的继续进行,故 LiOH能够抑制碱-硅酸反应发生膨胀.

Water absorption rate of products of silica reaction with KOH, NaOH and LiOH was studied. Test results show that the water absorption rate of KOH-silica reaction products is the highest followed by NaOH-silica reaction products, the water absorption rate of LiOH-silica reaction products is the lowest. The expansion of siliceous aggregate was compared in different solutions such as LiOH, KOH, LiOH+KOH and the products were studied by SEM/EDS. The results show that LiOH-silica reaction gives rise to less-expansive lithium silicate L-S-H which is fine and close in texture and unreacted aggregate is wrapped up in new-formed lithium silicate and alkali-silica reaction is prevented. LiOH-silica reaction process itself does not lead to expansion. When there is LiOH, K-S-H produced by KOH-silica reaction is transformed into L-S-H because K+ in K-S-H is replaced by Li+, therefore LiOH can inhibit the expansion due to alkali-silica reaction.