粉煤灰抑制砂岩碱硅酸反应.pdf

30 4 ( ) V o l. 30 N o. 4 200 8 7 JOURNAL O F NAN J ING UN IV ERS ITY OF TECHNOLOGY ( N atural Sc ence Ed t on) Ju ly 2008 杨立永, 邓 敏, 胡 勇 ( 南京工业大学 材料科学与工程学院, 江苏 南京 210009) : 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 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 20% 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 004% . 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 S 摩尔比. 低 Ca 与 S 摩尔比的 C- S- H 凝胶 + + 可以吸附更多的 N a K , 有效地抑制碱硅酸反应. : 碱硅酸反应; 砂岩; 粉煤灰; 抑制* : TQ1724+ 4 : A : 1671- 7627 ( 200 8) 04 - 0064 - 05 Inh ib ition of fly ash on alkalisilica reaction of sand stone aggregate YANG L yong, DENG M n, HU Y ong ( Co llege o f M ater a ls Sc ence and Eng neer ng, N anj ng U n vers ty o f T echno logy, N an j ng 210009, Ch na ) Abs tract: T he alka l s l ca react v ty o f sandstone aggregate and the effect o f a f ly ash on the nh b t on o f A SR ex pans on w ere stud ed by pe trog raph c exam nat on, acce lerated m o rtar bar test and concrete pr sm test. The results show ed that the sandstone aggregate conta n ng 5% to 12% m crocrysta ll ne quartz w as alka l s l ca react ve. Ex pans on rat o o f paste and concrete spec m ens decreased w th the ncreas ng of m x ng am ount o f the fly ash. Expan s on rat o of concrete specm ens w th alka l cem ent 20% , fly ash 30% or 40% was st ll below 004% after 24 m on ths. The alka l s l ca react on o f sandstone aggregate can be effect ve ly suppressed by the add t on of 30% gra