Measurement of the coefficient of thermal expansion of ultra-high strength cementitious composites using fibre optic sensors

Fibre Bragg Grating (FBG) sensors were embedded into cement mortar and ultra-high strength reactive powder concrete (RPC) prisms. Thermal tests are performed to accurately characterise the coefficient of thermal expansion (CTE) of these prisms using the measured signals from the embedded sensors. With the use of the fibre optic sensors, the difficulties inherent in using conventional techniques, such as strain gauges or vibrating wire gauges, to measure the thermal properties of cementitious materials are overcome. The error values associated with the measurements, typically measured to be as low as ± 0.04 με/K, are a full order of magnitude less than what is expected for standard conventional testing using a length comparator.