Application Of Infrared Thermal Imaging Method To Crack Detection Of Hydraulic Concrete

The concrete materials are widely used in water conservancy construction because of the advantages on its high strength,low cost,convenient construction and easy to get.However,under the influence of cement hydration,external load and natural disasters,cracks are easy to occur on the surface and interior of concrete.Especially for hydraulic concrete,the crack will affect the integrity and durability of the structure on a certain extent;it will also affect the bearing capacity of the structure and cause the engineering accident.Therefore,it is of great significance to find an effective non-destructive testing method to detect the location and size of cracks in concrete,and to provide reference for the quality evaluation of water conservancy projects.Based on this,the infrared thermal image method is used in the paper to detect the internal defects of concrete,and the following research work is carried out:(1)Introduce the application and research status of non-destructive testing method and the infrared thermal image technology.Respectively expounds the infrared thermal image theory;induction heating theory and concrete heat conduction theory.(2)The infrared thermal image method which based on radiation heat source was used to detect concrete cracks.The far infrared quartz heating plate and solar radiation were selected as heat source to thermal excitation the surface of concrete specimen.The temperature distribution of the surface of the concrete specimen and the change of the surface temperature with time will be fond by collecting the temperature data of the surface,through analyze the results to locate the cracks and to determine the size.(3)The infrared thermal image method which based on induction heating of steel bars was used to detect the internal concrete cracks.The internal steel bars of the concrete specimen are heated by high frequency induction heating apparatus.The temperature distribution of the surface of the concrete specimen and the change of the surface temperature with time will be fond by collecting the temperature data of the surface,through analyze the results to locate the cracks and to determine the size.