电阻率法研究氯化钠对水泥砂浆强度的影响

The influence of sodium chloride on the strength of cement mortar using electrical resistivity method

以掺加不同氯化钠质量浓度的水泥砂浆为研究对象,经过不同龄期的标准养护,考虑电流频率对电阻率值的显著影响,研究了其在不同频率下的电阻率和无侧限抗压强度,建立了水泥砂浆的无侧限抗压强度与电阻率的定量关系。结果表明:不同龄期、不同氯化钠质量浓度下,水泥砂浆试块的电阻率均随电流频率的增大而明显降低,合理的电流测试频率范围以50kHz为宜;不同氯化钠质量浓度下,水泥砂浆试块的无侧限抗压强度与电阻率均随龄期的增加经历快速增长和缓慢增长两个阶段;不同龄期下,水泥砂浆试块的无侧限抗压强度与电阻率均随氯化钠质量浓度的增加历经增强、平稳和减小3个阶段。

The mechanical behavior of the cement mortar samples is investigated which are prepared with various sodium chloride contents and different curing time.Considering the significant influence of current frequency on the electrical resistivity of the sample,the electrical resistivity and unconfined compressive strength are measured.The results show that under different curing time and sodium chloride contents,the electrical resistivity decreases significantly with the increaseof the current frequency.A working range of current frequency is suggested,while testing at frequency of 50 kHz gives the most suitable result.It is also seen that both the block’s unconfined compressive strength and electrical resistivity increase rapidly first and then fatten off with the increasing of age for samples with varying sodium chloride contents.However at different ages,both the block’s unconfined compressive strength and electrical resistivity increase firstly,then are stabilized followed by dropping off with the increasing of sodium chloride content.A quantitative relationship between unconfined compressive strength and electrical resistivity is estab-lished.