高阻抗高抗渗混凝土及其微结构特征

MICROSTRUCTURAL CHARACTERISTICS OF CONCRETE WITH HIGH IMPEDANCE AND IMPERMEABILITY

采用正交设计方法研究了矿物掺合料(粉煤灰和矿渣微粉)、轻集料(页岩陶砂)和聚合物(聚乙烯醇可再分散性乳胶粉)复合使用对混凝土电阻率和抗氯离子渗透性能的影响,上述材料对混凝土电阻率的影响效果由大到小的顺序依次为:聚合物、矿物掺合料、轻集料,对抗氯离子渗透性能的影响效果由大到小的顺序依次为:轻集料、矿物掺合料、聚合物。当矿物掺合料取代30%的水泥(质量分数),且其中粉煤灰和矿渣微粉质量比为3:7,轻集料取代河砂的体积率为30%,聚合物掺量为胶凝材料总质量的1.5%时,混凝土具有最佳的高阻抗和高抗渗特性。3种功能材料复掺明显提高了混凝土密实程度,优化了混凝土的界面过渡区,并且聚合物在水泥石和集料界面能够成膜,从而使得混凝土具有高阻抗和高抗渗的特性。

The influences of mineral admixtures（fly ash and slag）,light weight aggregate（shale sand） and polymer（Polyvinyl alcohol（PVA） redispersible powder） on concrete impedance and anti-chloride permeable ability were studied by orthogonal experimental design.The increased effects of them on concrete impedance are polymer,mineral admixtures and light weight aggregate in turn.The enhanced effects of them on concrete anti-chloride ion permeability are light weight aggregate,mineral admixtures and polymer in turn.Concrete can obtain best impedance and anti-chloride ion permeability,when the mass of cement replaced by mineral admixtures is 30%,the mass ratio of fly ash and slag is 3：7,the volume of river sand replaced by light weight aggregate is 30% and the mass of polymer is 1.5% to total gel materials.Moreover,the relationship between micro-structure and these characters of concrete is also studied.The results show the compact rate of concrete is improved because of these materials used,the research also find the interfacial transition zone is optimized and polymer film is formed between aggregate and harden cement paste,these effects of them on concrete micro-structure are good for concrete getting higher impedance and anti-chloride ion permeability.