氯离子在掺不同矿物质掺合料高性能混凝土中的扩散性能(英文)

CHLORIDE IONS DIFFUSION PROPERTIES IN HIGH PERFORMANCE CONCRETE WITH DIFFERENT POSSOLANTIC MATERIALS

采用改进型电迁移法测试了氯离子在掺不同矿物质掺合料高性能混凝土中的扩散性能。研究表明:在混凝土中分别内掺磨细矿渣、粉煤灰、硅灰、膨胀剂均可提高混凝土的抗渗透性能(Cl-扩散系数降低),其中以单掺硅灰效果最优;在混凝土中复掺膨胀剂和磨细矿渣或膨胀剂和粉煤灰,对提高混凝土抗渗透性能的效果优于单掺二者之一,也优于单掺效果最好的硅灰混凝土。复掺膨胀剂和细掺料后混凝土内部结构进一步优化、微观结构致密、微缺陷减少,由此,开发了一种低成本配制超高抗渗性混凝土的新途径。

The diffusion property of chloride ions in high performance concrete (HPC) by addition of different possolantic materials was tested by modified electrical immigration (NEL). The results reveal that the impermeability of HPC with any one of the following additives of grounded blast furnace slag (GGBFS), fly ash, silica fume (SF), and expansive agent is improved, and diffusion coefficient is decreased. The concrete with SF has the best impermeability among all the additives. It is also found that the impermeability effect is much better by mixed addition of expansive agent and GGBFS or fly ash in HPC, than mono addition of each one and even better than mono addition of SF. The reason is that the inner structure of concrete is improved by mixed addition the microstructure becomes denser and micro defects are lessened. A new economical technical route of preparation of super-high impermeability concrete is developed.