锂渣粉对碱-硅反应的抑制效果及其自身微膨胀的分离

Suppressing effect of lithium slag on alkali-silica reaction and separation of its self-expansion

为了客观评价锂渣粉抑制碱-硅反应（ASR）的效果，进行了锂渣粉抑制ASR的试验和分离锂渣粉自身微膨胀的试验．用砂浆棒快速法对比了锂渣粉与粉煤灰单掺或复掺对ASR的抑制效果，当掺量为20％时，锂渣粉的抑制效果为76％，而粉煤灰的抑制效果可达93％，表明同掺量下锂渣粉对ASR的抑制效果远不如粉煤灰．采用砂浆棒快速法，使用非活性大理岩骨料测试在锂渣粉掺量为0，10％，20％，30％时的膨胀率，计算得到不同掺量下锂渣粉产生的微膨胀（膨胀率约0．005％～0．015％），然后从相应锂渣粉掺量下采用活性砂岩骨料时的膨胀率中减去锂渣粉的微膨胀，从而从锂渣粉抑制活性骨料ASR效能试验的膨胀值中分离出锂渣粉产生的自身微膨胀．采用60℃快速混凝土棱柱体法，进一步证实了混凝土中锂渣粉导致的早期微膨胀以及锂渣粉对ASR的抑制效果．结果表明：锂渣粉会导致砂浆或者混凝土在早期发生微膨胀；测试锂渣粉抑制ASR的效果时，需分离这种微膨胀；锂渣粉掺量为30％以上时，可有效抑制砂岩骨料的ASR，抑制效果约89％，略逊于同掺量粉煤灰的典型抑制效果．

For the proper evaluation of the suppressing effect of lithium slag on alkali-silica reaction （ASR）, tests on the suppressing effect of lithium slag on ASR and the separation of its self-expansion were performed. The suppressing effects of the lithium slag or fly ash on ASR were compared by use of the accelerated mortar bar test （AMBT）. The effect with 20% of the lithium slag to inhibit ASR expansion was 76%, while that with 20% of fly ash was 93%, indicating that under the same replacement content, the suppressing effect of the former was greatly smaller than that of the latter. The self-expansion of the lithium slag with the content of 0, 10%, 20% and 30% in AMBT （the corresponding expansion rate was about 0.005% to 0.015% ） was obtained by use of non-reactive marble aggregate, and then was subtracted by that with the corresponding content by use of the reactive sandstone aggregate. Thus the self-expansion of the lithium slag was separated from the tests on the effect of lithium slag on ASR of reactive aggregate. The 60℃ accelerated concrete prism tests were conducted to verify the early expansion of concrete due to the lithium slag and its effect on ASR. The results show that the lithium slag will cause early expansion of mortar or concrete, and this expansion should be separated when the suppressing effect of the lithium slag on ASR is studied; with 30% or more of the lithium slag, ASR of the sandstone aggregate will be effectively reduced by 89%, and the effect is only a little lower than that of typical fly ash with the same replacement content.