ULTRASONIC NON-DESTRUCTIVE TESTING OF CONCRETE STRUCTURES COMPACTNESS UNDER CIRCUMSTANCES OF QINGHAI-TIBET PLATEAU

The environmental conditions of Qinghai-Tibet Plateau lead to the problem of compactness defects in concrete. Accurate non-destructive testing of concrete compactness defects is the key to ensuring the bearing capacity and durability of the structure. In this study, one ultrasonic pulse velocity (UPV) calculation model was established for the concrete entity part with air pressure and water-cement ratio as calculation parameters upon the UPV calculation model of concrete entities under different air pressures and combined with the results of the previous concrete ultrasonic tests carried out on Zangmu Bridge of Yarlung Zangbo River in Tibet and Nanning of Guangxi; and further calculated and analysed the UPV of concrete under the conditions of different porosity, of defects, and of aggregate distribution to reveal the influence regularity and mechanism of porosity and defects on UPV of concrete, to study the influence rule of aggregate distribution proportion on ultrasonic test results of concrete, to establish a multi-factor calculation model for overall UPV of concrete, and to propose a statistical analysis method of concrete compactness based on UPV. It is hoped that this study can provide a theoretical basis for the analysis of ultrasonic non-destructive testing results of concrete structure compactness in practical engineering.