水泥砂浆的低温电导率与温度关系及NaCl的影响

Relationship Between Conductivity and Temperature of Cement Mortar at Low Temperature and the Effect of NaCl

研究了水灰比为0.50~0.65的水泥砂浆分别经烘干、纯水饱和及5%NaCl溶液饱和后在-21--12℃之间的电导率。结果表明,经60℃烘干的水泥砂浆的电导率随原始砂浆水灰比的增大而降低,电导率的对数与绝对温度的倒数呈线性关系,成型水灰比不同的烘干水泥砂浆的离子迁移表观活化能差别较小;纯水饱和砂浆电导率的对数随绝对温度的倒数变化曲线在1/T=3.72×10-3 K-1（即约-4℃）附近存在一个明显的转折点,用5%NaCl溶液饱和的水泥砂浆的电导率显著高于纯水饱和砂浆,且电导率的对数随绝对温度的倒数变化曲线上的转折点降低到-7℃左右。

The relationships between the conductivity of cement mortars and the temperatures between --20 ℃ and 10 ℃ were studied. The mortars were prepared with the water-to-cement ratios （w/c） between 0. 50 and 0. 65, and pretreated by three ways, dried at 60 ℃, saturated with water and saturated with 50//00 NaC1 solution, respective- ly. The results show that the conductivities 0f the dried cement mortars decrease with their original water-to-cement ratios. There are linear relationships between the logarithms of conductivity （lga）and the reciprocal of temperatures （1/T）. The apparent activation energies of ion migration in dried mortars prepared with different water-to-cement ra- tios are basically the same. There are turning points at about --4 ℃ （1/T=3.72×10 -3 K-2） on the lgo-1/T curves of the water saturated mortars. The NaCI solution saturated mortars have much high conductivities and the turning points reduced to about --7 ℃.