Study On AC Impedance Characteristics Of Sodium Hydroxide Cemented Soil

Macroscopic methods used to be mostly adopted to test the basic characteristics of cement soil materials in the past, however such methods would do great damage to the original specimen and in the same time the macro approach requires a number of money, manpower and material resources; While the relatively new methods of studying the properties of cement soil such as scanning electron microscopy method, the heat of solidification method, resistivity method and so on, these methods are respectively made quite big progress in certain aspects compared to the traditional methods, but they also have their own limitations.Against the disadvantages of traditional methods, a kind of convenient, non-destructive, quick, economic and more comprehensive method was introduced in this paper-AC impedance method. To simulate the environment polluted soil with sodium hydroxide solution soaking soil, after treatment of the soaked soil, then mixing it with cement in a certain proportion to simulate the polluted cemented soil, through the laboratory experiment, using TH2828A precision LCR digital bridge to carry out electrical tests. According to the tested Impedance parameters to reveal changing law of the AC impedance parameters with pollution level, concentration (or content), age and the unconfined compressive strength.The main research conclusions are summarized as follows:(1)The Bode figure of cement soil test block before and after pollution shows the same rule, the impedance value decreases with the increase of frequency.(2)The unconfined compressive strength of cemented soil specimens and its curing period have a certain correlation. Unconfined compressive strength of cement-soil increases as the growth of the age, but the late strength increases more and more slowly age of more than thirty days after the intensity is still significantly enhanced.(3) The impedance parameters|Z|, Z’and unconfined compressive strength of the cemented soil specimen maintain a high degree of correlation, it also shows the feasibility that AC impedance method can be used to indirectly reflect the strength, which is expected to provide a kind of nondestructive, simple, powerful way to test finished cemented soil products.(4)Impedance parameters of soil cement specimens|Z|and content of pollutants in cemented soil sodium hydroxide has a relatively high correlation, which can be fully explained to infer the extent of contamination by measuring electrical parameters, and thus can be considered as a evaluation of an indicator of mechanical properties of cemented soil(5)The unconfined compressive strength of cemented soil specimens and the content of sodium hydroxide pollutants in soil have good correlation, and the Ac impedance parameters of cemented soil pollution levels have good correlation. In turn, we can establish the contact between pollution degree and unconfined compressive strength by measuring electrical parameters of contaminated cemented soil, which fully shows that the feasibility of the physical and mechanical properties of quantitative nondestructive specimens through the contaminated degree.