Investigation Intothe Correlations Between Compressive Strength And Microwave Characteristics Of Cement-based Materials

At present,China is the world’s largest producer and consumer of cement-based materials.However,the study of the microwave properties of cement-based materials for Chinese national standard failed to make great achievements.With the widespread application of non-destructive testing technology(NDT),the requirements for structural health monitoring(SHM)in civil engineering are also increasing.In this paper,cement-based materials are the main research object,through the study of its compressive strength and microwave characteristics,and also the study via regression analysis of measurement data,the correlations between of the compressive strength and microwave characteristics have been established.In the course of this study,the study object is divided into two parts,namely engineering cement composite material(ECC)and the commonly used ‘Guo Biao’(GB)concrete with various strength grades.In the course of experiments,in addition to the traditional destructive compressive strength test of cement-based materials at different ages,the non-destructive testing technology(NDT)was used to test theeffective conductance of ECC materials and the dielectric constant of GB concrete materials.In order to achieve the main purpose of this paper,which is the correlation between compressive strength and microwave properties of cement-based materials.In the process of preparation,the cement-based materials with different initial moisture content were prepared.According to the different age of curing,the correlations between the effective conductance and compressive strength of ECC materials was studied,and the correlation between dielectric constant and compressive strength was studied also.In the microwave characteristic measurement test,the bi-exponential regression function model,the first-order exponential regression model,the Debye model and the Jonscher model were used to fit the measurement data.Through the comparison of the values of ‘goodness of fit’ for each model,the relationship between cement-based materials’ microwave characteristics and age has established.In addition,the relationship between compressive strength and age of cement-based materials was established by compressive strength test.Finally,the correlations between compressive strength and microwave properties of cement-based materials were established based on the age of cement-based materials.The main contributions of this paper are as follows: The correlation model between compressive strength and effective conductance of ECC materials at 2GHz frequency is established.The correlation model between compressive strength and dielectric constant of GB concrete in the frequency range of 100 MHz to 6GHz is established.