化学外加剂对混凝土气孔结构及水化的影响

Effect of chemical admixtures on air void structure and hydration of concrete

通过化学外加剂来调节混凝土内部的气孔结构，研究调控组分H对掺有引气剂混凝土气孔结构、性能的影响规律，并利用X射线衍射（XRD）及热重-差示扫描量热（TG—DSC）分析方法，研究了化学外加剂对水泥浆体水化产物及水化进程的影响。研究表明，H掺量为0．2‰时，混凝土的综合性能达到最佳；当掺加调控组分混凝土（KH2）总孔隙率与基准混凝土（K）相近时，增加10～200μm范围孔径的孔隙率，减少200～1600μm范围孔径的孔隙率，使平均孔径及气泡间距系数减小，抗压强度提高；化学外加剂掺加到水泥浆体中，并没有新的晶相生成，并且对水泥浆体水化进程没有明显影响。

The effects of the regulated components （H） on the air void structure and properties of air-entraining concrete were studied. In addition, the hydration degree and the phase compositions of cement pastes were studied by thermogravimetry-differential scanning calorimetry （TG-DSC） and X-ray diffraction （XRD）. The results showed that when the dosage of H was 0.2 N0, the concrete achieved the best comprehensive performance. The average air void diameter and mean free spacing in air-entraining concrete were decreased and its compressive strength could be improved due to the increase of the porosity of the air void size ranging from 10 to 200μm and decrease of the porosity ranging from 200 to 1 600 μm. Furthermore, the effect of chemical admixtures on the degree of cement hydration was not remarkable and no formation of new phase in cement pastes.