作　　者： ; ; ;

机构地区： 中南大学土木建筑学院

出　　处： 《铁道科学与工程学报》 2004年第2期46-51,共6页

摘　　要： 采用ASTMC12 0 2推荐的快速试验方法———直流电量法 ,研究了水灰比以及粉煤灰和硅粉两种矿物掺合料对混凝土抗氯离子渗透性能的影响。试验结果表明 :水灰比降低 ,虽然可以降低混凝土 6h库仑电量 ,但并不能有效地提高混凝土抵抗氯离子渗透能力 ,只有掺入矿物掺合料才能有效解决这一问题。单掺粉煤灰可以降低氯离子在混凝土中的渗透性 ,且随着粉煤灰掺量的增加 ,混凝土渗透性降低 ;粉煤灰的细度对混凝土 2 8d龄期前的渗透性有较大的影响 ,而对后期的影响较小。单掺硅灰显著降低混凝土 6h库仑电量 ,而且硅灰与粉煤灰复合双掺可进一步改善混凝土的抗氯离子渗透性。综合考虑 ,少量的硅灰与粉煤灰复合双掺是配制具有极低氯离子扩散渗透性混凝土的重要技术途径。 This paper studies the effects of water-cement ratio, two minerals admixtures of fly ash and silica fume on penetration of chloride ions into concrete by the rapid chloride permeability test method as designated in ASTM C1202.The experimental results show that the decrease of w/c can reduce the penetration of chloride ions into concrete, but it is not effective enough in improving the resistance to penetration of chloride ions by decreasing water-cement ratio, and only when mineral admixtures were added into concrete can this problem be effectively solved. The concrete containing fly ash can decrease the penetration of chloride ions into concrete, and the larger the fly ash content is, the lower the permeability of concreteis. The fineness of fly ash has great influence on the permeability of concrete within 28-day ages, and has less influence on that of in later age. The addition of silica fume can evidently decrease the penetration of chloride ions into concrete, and the resistance to penetration of chloride ions into concrete can be further improved by combining silica fume with fly ash added into concrete. This indicates that the important technical way to prepare the concrete with lowest penetration of chloride ions is the addition of the composite of fly ash and silica fume taking account of all factors. The packing role and pozzolanic effects of minerals admixtures are mainly responsible for the improvement of resistance to penetration of chloride ions into concrete.

关 键 词： 矿物掺合料 高性能混凝土 氯离子渗透性能 直流电量法 粉煤灰 硅灰

领　　域： [建筑科学]