利用饱碱电导表征掺矿物混合材混凝土的渗透性

PERMEABILITY OF CONCRETE WITH MINERAL ADMIXTURES INDICATED BY ALKALI SATURATED CONDUCTIVITY

混凝土掺矿物混合材后孔溶液电导变化较大,将试件抽真空后以1 mol/L的KOH溶液饱和毛细孔隙(饱碱),可减小孔溶液对混凝土电导的影响,使电参数真实反映孔结构和渗透性的变化。检测了掺加矿物质混合材后混凝土试件的饱碱电导和6 h通电量。利用压汞法分析了相应净浆试件孔结构特征,并检测了氯池(6%NaCl溶液)浸泡300 d后氯离子在净浆试件中的渗透情况。结果表明:基准试件的饱碱电导最大,掺10%硅灰的混凝土饱碱电导最小。

Pore solution conductivity of concrete changed considerably when mineral admixtures were incorporated. The saturation of the concrete capillary pore system with 1 mol/L KOH solution by vacuum processing （alkali saturation） reduced the effect of the pore solution on the concrete conductivity. The pore structure and concrete permeability were characterized accurately with electric parameters. The conductivity of alkaline saturated concrete and the 6 h charge passed were measured, pore structure of the corresponding pastes was tested by mercury intrusion, and chloride diffusion in pastes was also conducted by chloride ponding test after immersion in NaCl solution for 300 d. The alkali saturation test show that the alkali saturated conductivity of the controlled specimen is the greatest and the conductivity of the 10% silica fume-hearing concrete is the smallest.