Research On The Single Surface Test Method Of Ultrasonic Waves Reflection On Interface Of Bond Quality Between Steel And Concrete

The adhesive interfaces between steel and concrete can be widely seen in engineering, such as concrete filled steel tube, the bottom of large equipments with steel plate, reinforced structures with bonded steel plate and so on. The bonding quality of the steel and concrete is of great importance to the structure, as it may affect the security of the structure and the stability of the equipments'operation directly.In the past, the ultrasonic transmission method was widely adopted to test the bonding quality of the steel and concrete. In the method, two transducers were deposited by the two opposite sides of the test member in experiment. Based on the attenuation of energy received after the pulse wave penetrates through the test surface, the interior faults can be detected. However, usually in practical use, only one surface can be found to place the transducer, which puts forward a new demand to our test method. Therefore, it is of great practical value to find a reasonable nondestructive test method to estimate the bonding quality of the reinforced concrete in engineering.In this paper, the reflection method of ultrasonic longitudinal wave and that of ultrasonic shear wave to test the bonding quality of the adhesive interface between steel and concrete from single-surface is adopted respectively. When the energy converters and the thickness of the steel plate are settled, the attenuation speed of the repetitious pulse reflected wave from the underside is only related to the reflectivity of the reinforced concrete interface. Therefore, the judgment presented here is according to the attenuation coefficient and number of the bottom wave.Considering the actual testing, the influences of such factors as the thickness of the steel plate, the moisture content of the concrete and oil paint layer on the test are taken into account in experiment. The test results indicate that the above factors do not have much effect on ultrasonic longitudinal wave testing. However, the setting and hardening time of the concrete, the mortar influences the test results obviously. So the suggestions of the concrete and mortar to be tested after 7 days and the epoxy resin mortar to be tested after 3 days are given.According to the test results from 18mm-thick-steel plate adhering to concrete, gas and oil, the obvious differences in the attenuation coefficient and number of bottom waves are found. The test results shows that it is feasible to adopt ultrasonic longitudinal wave reflection method to test the bonding quality of the steel and...