Ultrasonic monitoring on glass fiber reinforced cement (GRC) bending test

Glass fiber reinforced cement (GRC) is a composite material based on Portland cement and alkali resistant glass fibers. This composite has good mechanical properties including toughness and flexural strength. The characterization of this material is carried out by four points bending test. During this test, elastic and plastic behaviour are identified from load vs. deflection curves. The scope of the research is to monitor this bending test by means on ultrasonic pulses in order to detect changes on the material and to correlate them with mechanical behaviour. In this sense, pulse velocity, energy, attenuation and non-linearities of the ultrasonic received signals have been analysed. First changes in energy, attenuation and non-linearities were detected during the change from elastic to plastic step and the first pulse velocity change were observed during the plastic step