Research on Real-Time Monitoring of Strain Behavior of Concrete under Freezing-Thawing Cycle by White Light Interferometer

Abstract

To study the degenerative process of concrete subjected to freezing-thawing (F-T) cycles in real-time, the strain behavior of concrete cylinder was monitored by a fiber optic F-T testing method based on the white light interferometer (WLI) technique. The principle of the WLI technique was described in detail and the design of the fiber optic testing method. Two mixed proportions of concrete immersed in 3.5% NaCl solution were tested in a freeze-thaw testing machine. The theory and method of temperature compensation were stated in detail. The results indicated that the variation of strain decreases in the cooling stage and increases in the heating stage in a F-T cycle. The residual strain was generated in the test.