Non-Destructive Detection Of High Strength Concrete With Polypropylene Fiber Exposed To High Temperature By Infrared Thermal Imaging And Ultrasound

As the frequent occurrence of fire, lives and property of peoples in the world are subject to greatly threatened. Building fires is extremely serious in all fire damage, for it will be related to people's life safety. Therefore, the study of building's damage under fire conditions and detection methods have important economic significance and engineering value for structural design and establishment of fire prevention measures, coordination and command of safe evacuation in fire,fire attack and, and the Assessmen of building's Damage after fire,building repairthis text, high-strength concrete structural damage detection and analysis as the background, do fast,comprehensive non-destructive testing to the buildings with infrared thermography and ultrasonic detection NDT technology, in order to achieve comprehensive visualization rapid monitoring and analysis for high strength concrete damage purposes. With the help of infrared thermography and ultrasonic detection technology we can make a comprehensive detection with the damage of concrete. This is about to use infrared cameras and ultrasonic detectors to detect inside deformation and damage of the fired concrete structure, and related to this issues do a large number of experimental studies and exploratory theoretical analysis.Studied in this text is theoretical analysis based on relevant results, and experimental study of detection of concrete defect with infrared imaging method and Ultrasonic inspection method, in order to find a viable non-destructive testing method to detect internal defects in concrete.This paper carried out research in the following areas:1.make a comprehensive and systematic analysis and discussion of fire damage identification of concrete and status of non-destructive testing technology research and development at home and abroad, and point out the advantages and disadvantages of each testing technology, and introduces infrared imaging detection technology and ultrasonic inspection technique in detail.2. Introduced the principle of infrared non-destructive testing technology, a large number experiments of internal damage detection of high-strength concrete after fire by using infrared camera, and the analyzing and summarizing of experimental results. With the help of infrared imaging detection get the data of distribution of surface temperature, then solving the average temperature rise of specimen, establish correlativity of the average temperature rise of specimen,the specimen fire temperature and specimen damage; achieve determining of the nature and localization of specimen defects. The achievement develop a more extensive world for increase the efficiency and accuracy of infrared and ultrasonic nondestructive testing technology to detect high-strength concrete defects, improve the practical significance of infrared imaging and ultrasonic testing in nondestructive detection technology of concrete structures,and practical application of infrared imaging detection technology and ultrasonic inspection techniques.3. Through the ultrasonic nondestructive testing to high-temperature high-strength concrete specimens, ultrasonic velocity down with the fire temperature increasing. Get the correlation of the speed of sound and residual compressive strength, splitting tensile strength of concrete after different grades of fire temperature. Using the methods of mathematical statistics and regression analysis to get the correlation between high-strength concrete fire temperature and ultrasonic velocity, the residual compressive strength of concrete after fire, splitting tensile strength and the speed of sound.Based on research and analysis of the strength of concrete with different dosage of polypropylene fiber after high temperature mechanical properties and infrared testing and ultrasonic testing, obtained some research results, establish the foundation of the future study of high-temperature characteristics of high strength concrete.