The Application ofa new technique to determine the beginning of the setting time for cement-based materials

摘要

Waves, in general, can be characterised as a physical phenomenon. Mechanical waves occur in the environment, which is composed ofparticles between which there is a bond. In this material, the forced oscillation ofone particle is progressively transferred to the other particles, with environmental particles not moving in the space but only oscillating around equilibrium positions and they are simultaneously deforming. The oscillation progresses at a certain speed from its source at some points, either in the plane or in space. In order to analyse the change ofmechanical waves passing through fine-grained cement-based composite material during setting and hardening, a suitable experimental technique is needed. The main aim ofthis paper is a description of the non-destructive method, which will be used mainly to monitorthe signal amplitude change during the setting and hardening ofcement-based materials. The measuring set was composed fortius purpose from the equipment ofthe Brno University ofTechnology. The form for the testing ofcomposites is made in the same size as the Vicat's ring. The own measurement ofthe signal will be done on the DAKEL XEDO acoustic analyser. The main advantage of the method is its non-destructive character. The first results show the obtained results could be used to determine the initial setting time ofthe cement-based composites.