Ultrasonic detection method of freeze-thaw damage thickness of concrete

The freeze-thaw damage thickness of concrete is very important to assess the damage of structures. Such research at present is relatively small. For quantitative analysis of freeze-thaw damage thickness of concrete structure, this paper conducted a quick freezing method, entraining concrete test beam is immerged with 3.5% NaCl salt solution to freeze test. Based on ultrasonic detection methods, non-metallic ultrasonic instrument was used to detect concrete test blocks after 300 freeze-thaw cycles using multi-level measurement methods. Four test blocks were tested, each test block was tested 3 times. The formula of derivation of stress wave in the structures. The test data was analyzed and the damage thickness of concrete was achieved. The results show that: The damage thickness of concrete test blocks after 300 times freeze-thaw cycles and this value is less than the protective layer of steels.