超细活性硅微粉对混凝土耐久性影响研究

Effect of ultra-fine active silica powder on concrete durability

通过混凝土冻融循环试验、碳化试验及氯离子渗透试验研究了超细活性硅微粉对混凝土耐久性能的影响。首先对比研究了基准混凝土、掺超细活性硅微粉及硅灰混凝土的抗冻性能、抗碳化性能及抗氯离子渗透性能。并用扫描电子显微镜(SEM)等微观测试手段研究了基准混凝土、掺超细活性硅微粉及硅灰混凝土中水泥石的微观结构。试验结果表明:适量的超细活性硅微粉能够明显改善混凝土的抗冻、抗碳化及抗氯离子渗透等耐久性能,超细活性硅微粉能有效降低水泥石中的氢氧化钙含量,改善水泥石的微观结构,使水化硅酸钙凝胶增多,水泥石的微观结构更加致密,从而提高混凝土的耐久性能。

The effects of ultra-fine active silica powder on the durablities of concrete were studied by the methods of freezethraw test and carbonation test.Firstly,the freezethraw durability,carbonation resistance and ability to resist chloride ion penetration of pure concrete,ultra-fine active silica powder conrete and silica fume concrete were comparatively studied.The microstructure of pure cinrete,ultra-fine active silica powder conrete and silica fume concrete were researched by scanning electron microscopy test.The results showed that conditions in the appropriate mixing amount,ultra-fine active silica powder can significantly improve the durabilities of concrete.The content of free lime in concrete could be significant reduced by adding appropriate mixing amount of ultra-fine active silica powder.Therefore,the micreostructure of cement pastes were improved.Consquently,it could improve the durabilities of concrete.