砂岩骨料的碱活性检测与抑制试验

Tests of detection and inhibition of alkali aggregate reactivity for sandstone

用岩相法、砂浆棒快速法、溶胶-凝胶膨胀法和混凝土棱柱体法,联合研究了砂岩骨料的碱硅酸反应(ASR)活性,评价了粉煤灰对该砂岩ASR膨胀的抑制效果.试验结果一致表明了该砂岩骨料具有潜在的ASR活性,其碱活性主要来自于玉髓状微晶石英和波状消光石英.采用20%的Ⅰ级粉煤灰替代水泥,可以把这种砂岩的ASR膨胀量控制在非碱活性范围之内.

The alkali-silica reaction （ASR） of sandstone aggregate is determined by means of petrographic examination, mortars-bar test and sol-gel expansion test as well as concrete prism expansion method; and the effect of fly ash on inhibiting the ASR expansion occurred in the sandstone is evaluated. The experimental results congruously show that the sandstone aggregate is alkali-silica reactive, and the reactivity mainly results from chalcedonic microcrystalline quartz and undulated extinction quartz. The expansion value due to ASR for the sandstone can be reduced to a non-reactive range by substituting cement with 20% first grade fly ash.