NaOH溶液浓度对硅质集料和白云质集料岩石柱膨胀的影响

Effects of NaOH solution concentration on expansion of rock-prisms of siliceous and dolomitic aggregates

改进岩石柱法研究硅质碱活性组分分散分布在岩石中的硅质集料和白云质集料岩石柱在80℃不同浓度的NaOH溶液中的膨胀性。结果表明:当NaOH溶液浓度分别为1.00和0.50 mol/L时,硅质集料和白云质集料岩石柱均可产生显著膨胀,当NaOH浓度低至0.25 mol/L时,硅质集料岩石柱不膨胀或轻微膨胀,白云质集料岩石柱膨胀显著。当NaOH浓度为0.10 mol/L时,硅质集料岩石柱不膨胀,白云质集料岩石柱膨胀。岩石柱法可以用于评定硅质碱活性组分分散分布集料的碱硅酸反应活性,当养护溶液为80℃、0.25 mol/L的NaOH溶液时,采用岩石柱法可判定白云质集料是否具有碱碳酸盐反应活性。

The expansibility of siliceous aggregates with distributed alkali-silica reactive components and dolomitic aggregates was evaluated by the modified rock-prism test method in which different concentrations of NaOH solution at 80 ℃ were used.Results showed that significant expansion was recorded on the rockprisms prepared with siliceous aggregates and dolomitic aggregates cured in 1. 00 and 0. 50 mol/L NaOH solutions at 80 ℃. When the concentrations of NaOH solution were not more than 0. 25 mol/L,little expansion was measured on the rock-prisms of the siliceous aggregates. However,obvious expansion was detected on the rock-prisms of dolomitic aggregates soaked in 0. 25 or 0. 10 mol/L NaOH solutions at 80 ℃.The modified rock-prism test method could be used to evaluate alkali-silica reactivity of siliceous aggregates with distributed alkali-silica reactive components,and alkali-carbonate reactivity of dolomitic aggregates could be identified by testing rock-prisms in 0. 25 mol/L NaOH solutions at 80 ℃.