不同水灰比、硅粉和骨料对界面过渡区的影响

Effects of different water cement ratio,silica fume and aggregate on interfacial transition zone

界面过渡区对混凝土的耐久性和力学性能有重要影响。为提高混凝土的力学性能,通过光学显微镜观察不同水灰比、硅粉掺量和骨料类型下界面过渡区的微观组织,并借助显微硬度仪和万能试验机测量混凝土的显微硬度、抗压和抗折强度,研究水灰比、硅粉掺量对不同骨料与水泥浆体界面过渡区微观结构和力学性能的影响。结果表明:在水灰比较低时,界面过渡区骨料与水泥浆体的结合更加紧实;掺入硅粉可以改善界面过渡区的微观结构,随着硅粉掺量的增加,界面过渡区的裂纹减少,水泥净浆和含骨料混凝土的力学性能也随之改善;与花岗岩相比,以石灰岩为骨料时界面过渡区的显微硬度值更大。

The interface transition zone has an important influence on the durability and mechanical properties of concrete.In order to improve the mechanical properties of concrete,the microstructure of interfacial transition zone under different water cement ratio,silica fume content and aggregate type is observed by optical microscope,the microhardness,compressive and flexural strength of concrete are measured by microhardness instrument and universal testing machine,and the effect of water cement ratio and silica fume content on microstructure and mechanical properties of interfacial transition zone between different aggregates and cement paste are studied.The results show that when the water cement ratio is low,the combination of aggregate and cement paste in the interface transition zone is more compact;Adding silica fume can improve the microstructure of interfacial transition zone.With the increase of silica fume content,the cracks in interfacial transition zone decrease,and the mechanical properties of cement paste and concrete containing aggregate also improve;The microhardness of the aggregate is higher than that of the granite.