Application of Distributed Fiber Optic Sensor (DFOS) Technique for Measurement of Early-age Concrete Deformation

The deformation of cement-based materials within the first 24 hours after the casting procedure is highly relevant for the structural performance and durability of hardened concrete. There are numerous influence parameters on early-age concrete deformations, e.g. matrix composition, outside humidity and temperature, and much more. Therefore, the investigation of early-age concrete deformation was subject of many researches. Usually, early-age concrete deformations were measured with strain gauges, fiber bragg grating (FBG) sensors, and digital image correlation (DIC). The disadvantage of this methods is that deformations may be measured only at one point (FBG) or at the surface (DIP) of the structure. This can be overcome if distributed sensing technique is applied. Within the framework of the conducted experimental program, the distributed fiber optic sensor (DFOS) technique based on Rayleigh Scattering was used. It could be verified that DFOS is able to measure deformations with accuracy over the whole sensor length. DFOS has proved as valuable tool for control of plastic shrinkage and early cracking of concrete as a cause of subsequent impairment of durability and structural performance.