基于非接触电阻率测量法的水泥基材料早期水化特性研究

Study on early hydration characteristics of cement-based materials based on non-contact resistivity measurement

采用非接触电阻率测量法,基于电阻率与温差曲线,研究了硅灰掺量(5%、10%)和粉煤灰掺量(20%、40%)对水泥基材料早期水化的影响。结果表明:掺粉煤灰组水泥浆体的电阻率在约580 min前高于C组(基准组),在580 min后低于C组,而掺硅灰组水泥浆体正相反,在580 min后,掺硅灰组水泥浆体的电阻率高于C组;与C组相比,掺入粉煤灰后,水泥浆体的放热量减少,放热峰对应的时间延迟,而掺入硅灰后,水泥浆体的水化反应明显加快,放热峰对应的时间也随着硅灰掺量的增加而提前;相比于C组,掺粉煤灰组水泥浆体的凝结时间略微延长,掺硅灰组水泥浆体的凝结时间缩短;相较于掺入粉煤灰,掺入硅灰可以促进水泥水化,使水泥浆体微观结构更加致密。

The influence of silica fume content(5%,10%)and fly ash content(20%,40%)on early hydration of cement-based materials was studied by combining non-contact resistivity measurement based on resistivity and temperature difference curves.The results show that the electrical resistivity of the cement slurry mixed with fly ash is higher than that of group C(benchmark group)before about 580 min,and lower than that of group C after 580 min,while the electrical resistivity of the cement slurry mixed with silica fume is the opposite.After 580 min,the electrical resistivity of the cement slurry mixed with silica fume is higher than that of group C.Compared with group C,the addition of fly ash reduces the heat release of the cement slurry and delays the time corresponding to the heat release peak.However,the addition of silica fume significantly accelerates the hydration reaction of the cement slurry,and the time corresponding to the heat release peak also advances with the increase of silica fume content.Compared to group C,the setting time of the cement slurry in the fly ash group is slightly longer,while the setting time of the cement slurry in the silica ash group is shorter.Compared to adding fly ash,adding silica fume can promote cement hydration and make the microstructure of cement slurry more compact.