外加剂对水泥混凝土性能的影响研究

EFFECT OF ADMIXTURES ON THE PERFORMANCE OF CEMENT AND CONCRETE

在 8 0℃长期养护条件下 ,当碱含量为 2 5 %时 ,掺加Li Na摩尔比 0 6的Li2 CO3能长期有效抑制碱集料反应膨胀。研究发现 :集料活性越高 ,Li2 CO3对膨胀抑制效果越好。对于沸石化珍珠岩砂浆 ,在有效抑制碱集料反应膨胀的前提下 ,随着Li Na摩尔比进一步的增加 ,Li2 CO3对碱集料反应膨胀的抑制效果并没有得到相应的提高。此外 ,掺加Li2 CO3一定程度上降低了砂浆的抗压强度和抗折强度 ,掺量越大 ,强度降低越多。在相同碱含量条件下 ,掺加Li2 CO3能缩短水泥的凝结时间 ,且Li Na摩尔比越大 ,凝结时间越短。

At 80℃ curing condition, alkali aggregate reaction expansion could be long-term effectively inhibited by Li-2CO-3 at the alkali content of 2^5%.Also, the higher the alkali reactivity of the aggregate was, the better the inhibiting effect of Li-2CO-3 showed.To the mortars with Li-2CO-3 at the same Li/Na molar ratio, the inhibiting effect was raised when the alkali reactivity of the aggregate was increased. To the mortars with zeolitization perlite, if alkali aggregate reaction expansion was inhibited effectively, the effect of Li-2CO-3 on expansion was not raised correspondingly when the Li/Na molar ratio was further increased.In addition, both the compressive strength and the flexural strength of the mortars would decrease when Li-2CO-3 was added.The more Li-2CO-3 was added, the more the strength would decrease. At the same alkali content conditions, the initial and final setting time of cement was shortened when Li-2CO-3 was added and the higher the Li/Na molar ratio of Li-2CO-3 was, the shorter the setting time was.