Fiber Bragg Grating Sensors for Real Time Monitoring of Early Age Curing and Shrinkage of Different Metakaolin-Based Inorganic Binders

In this paper, we report on the experimental assessment of real-time temperature and shrinkage early age monitoring of geopolymer matrices, by means of embedded fiber Bragg gratings (FBGs). The FBG sensors were properly designed and packaged in order to discriminate shrinkage and temperature behaviors. The proposed system allows for controlling the rheology of the binding systems made by metakaolin geopolymer. Hence, a series of experiments were conducted on different kind of materials, and confirms that FBGs represent a valid method for simultaneous temperature and shrinkage measurements with a temperature resolution of 0.1 °C and strain resolution of 1 μϵ.