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Abstract
Fibre Bragg grating (FBG) sensors are used for the experimental investigation of two of the most important time-dependent properties of concrete: drying shrinkage and creep. A swept wavelenght system is used as the interrogation technique. The FBG sensors are embedded directly into structural grade concrete specimens. Standard mechanical method is used in parallel with embedded FBG sensors. Both mechanically and optically measured time-dependent strains are discussed. It is shown that the FBG sensors offer a better alternative to the conventional electrical and mechanical methods, in the measurement of long-term time-dependent strains.