摘要
采用岩相法、砂浆棒快速法、混凝土棱柱体法研究了砂岩集料的碱硅酸反应活性，并评价了粉煤灰对砂岩集料碱硅酸反应的抑制效果．实验结果表明，该砂岩集料含有5％～12％微晶石英，具有碱硅酸反应活性．砂浆和混凝土试件的膨胀率随着粉煤灰掺量的增大而减小．水泥碱质量分数为2．0％时，粉煤灰掺量30％和40％的混凝土试件养护24月膨胀率仍然小于0．04％．I级粉煤灰占胶凝材料质量分数大于30％，可以有效抑制砂岩集料的碱硅酸反应引起的膨胀．粉煤灰的加入降低了C-S-H凝胶中的Ca与Si摩尔比．低Ca与Si摩尔比的C-S-H凝胶可以吸附更多的Na^＋、K^＋，有效地抑制碱硅酸反应．
The alkali-silica reactivity of sandstone aggregate and the effect of a fly ash on the inhibition of ASR expansion were studied by petrographic examination, accelerated mortar bar test and concrete prism test. The results showed that the sandstone aggregate containing 5% to 12% microcrystalline quartz was alkali silica reactive. Expansion ratio of paste and concrete specimens decreased with the increasing of mixing amount of the fly ash. Expansion ratio of concrete specimens with alkali cement 2.0% , fly ash 30% or 40% was still below 0. 04% after 24 months. The alkali silica reaction of sandstone aggregate can be effectively suppressed by the addition of 30% grade I fly ash. The Ca/Si molar ratio in C-S-H gel was decreased due to addition of the fly ash, thus resulting in the fixation of more Na^ ＋ , K^ ＋.
出处
《南京工业大学学报（自然科学版）》
CAS
2008年第4期64-68,共5页
Journal of Nanjing Tech University(Natural Science Edition)
关键词
碱硅酸反应
砂岩
粉煤灰
抑制
alkali-silica reaction
sandstone aggregate
fly ash
inhibition
