Study On Basic Problems In Quality Evaluation Of Concrete Structure With Aging Disease And In Bonding Reinforcement

The main contents of the thesis are as follows: 1) The growth rule of concrete carbonization depth was studied, and the ARIMA (1,1,0) model was presented to forecast the carbonization depth. 2) It was discovered that the concrete crack distribution had the fractal character. It was presented that the fractal dimension value of crack distribution was an effective index to appraise the structural aging degree. 3) With Bayes method, a valuable analysis was attempted to evaluate objectively the concrete strength with ultrasonic - rebound method and rebound method together. 4) As quantitative evaluating methods of the concrete bonding face roughness, the power spectrum fractal method and the height difference fractal method were studied to determine the fractal dimension. 5) With the upper bound theorem of plastic limit analysis, the theoretical solution for shear strength of new-old concrete bond layer was deduced, and the factors, which affect the shear strength of bond layer, were also determined with failure mechanism. The relationship between the shear strength of bonding layer and its normal stress was expatiated under low hydrostatic stress-state. 6) The micro-mechanism of new-old concrete bond was analyzed, and the BP neural network models were established to predict the bond split- tensile strength and the bond flexure strength of new-old concrete.