Proceedings PaperHolographic Interferometry Of Concrete
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The knowledge of the deformational behaviour of concrete is of major importance in the design of concrete constructions. This behaviour has so far only been verified under practical situations. One of the reasons therefore is, that the available mathematical models have been derived from a large number of experimental findings and are not applicable straightforwardly to different particular cases. The macroscopic deformations due to the external loads considered in those calculations are in fact the summation of microscopic deformations of the different constituents of the heterogeneous material called concrete. Up to now little information is available on the deformational behaviour of those constituents. The use of coherent optical techniques allows us to investigate microscopic deformations, and so can give us information about the interaction of the individual material components. The phenomena we investigated were: I. the influence of the deformation properties of the mortar matrix and the granulate during the creep period. 2. micro crack formation under static load. 3. the atmospheric sensitivity of different compositions after drying. The coherent optical techniques available are holography and speckle correlation; the incoherent techniques, high frequency moire, photoelasticity, and white light speckling. This article will deal only with holography and it's the intention to demonstrate its usefullness in the study of concrete, with the restriction that only hypotheses had to be derived from this general survey as a base for more extensive research.