Developing an integrated technique to evaluate crack formation in reinforced concrete under uniaxial compression

Regularities of changes in the parameters of acoustic and electromagnetic emission and of forced electric response from reinforced concrete under uniaxial compression have been studied. It has been established that the main diagnostic criteria of the onset of crack formation are the emergence of high-amplitude signals of acoustic and electromagnetic emission; considerable changes in the spectral composition of the electric signal; a decrease in the maximum coefficient of correlation between the spectra of signals registered at different stages of loading as compared with the spectrum of the signal prior to loading; and hopping shift of the frequency at which the maximum correlation coefficient is observed. On-line monitoring and periodic inspection can be used to assess the onset of crack-formation processes.