Acoustic Emission Characteristics Study On Damage Degradation Of Reinforced Concrete In Corrosion And Loading Process

The corrosion of reinforcement is one of the major cause of deterioration in reinforcedconcrete structures in chloride environments. Corrosion lead to the cracking of concrete cover, the reduction of the concrete-steal bonding, and the loss of the structures integrity, consequently, and then the serviceability of concrete structures can be heavily affected. The affection mainly contains two aspects:corrosion expansion process and the serviceability of the structure. Therefore, it is important to consider the deterioration of concrete during the corrosion expansion and loading in engineering. In this paper, the reinforced concrete is the mainline. This paper focuses on the study of the whole cracking process of the concrete and the process of the deterioration of the corroded reinforcement concrete column using acoustic emission technology.The research results are as follows:(1) The corrosion process of concrete specimens is monitored by using acoustic emission technology, and then the process of concrete cracking is detailed analysed according to the analysis of AE parameter and the original phenomenological model. Acoustic emission parameter and frequency spectrum are also analysed in the study of concrete corrosion cracking mechanism. One-dimentional posision is carried during the whole corrosion expansion process in the use of acoustic emission location technology. Meanwhile the development of crack is also analysed dynamically.(2) According to the difference of corroded degree of reinforced concrete, the serviceability and damage evaluation with different corrode rate are studied. During the load process, AE parameters of the whole process are analysed. The produce of the inner macro-crack are predicted on account of b-value theory. On the basis of rate process theory, corrosion rate and AE parameter are involved, and then damage evaluation model of reinforced concrete column is built. A real-time monitoring of corroded reinforced concrete column and quantitative evaluation of the dmage are achieved.(3) On the basis of AE damage monitoring of reinforced concrete under axial loading, by comparing the parameter characteristic of corroded member and uncorroded member, parameter analysis, FFT and wavelet transform are did in different stage of damage. The variation of frequency distribution, band energy ratio with time and the influence of corrosion to the fracture mechanism are summarized, which can improve the accuracy of monitoring on the concrete stability.