Acoustic emission characterisation of calcium aluminate cement hydration at an early stage

In this paper, a new application of the acoustic emission (AE) technique is proposed. This non-destructive and in situ method, widely used in damage characterisation, permits us to follow the cement hydration at the early age from a few minutes to a few hours after mixing. The acoustic emission (AE) signals concerning a pure aluminous cement paste, (water to cement weight ratio=0.4; temperature of measurement: 20 °C) were recorded and analysed. A specific treatment of data deduced from a fracture process identification procedure was applied. Different filters were set on the AE signal duration based on the characteristic of amplitude distribution. From the value of AE signal amplitude, correlation with physical and chemical changes were found.. Based on the experiments, the relationship between the AE characteristics recorded during the tests and the different mechanisms, which take place during setting, was emphasised. The results showed that the new application of the AE technique can be considered as a valuable tool to study the hydration of a cement at young age.