COMPARISON BETWEEN OPTICAL MICROSCOPY AND SCANNING ACOUSTIC MICROSCOPY FOR DETECTING FLAWS IN CONCRETE

Concrete was regarded for a long time as an eternal and maintenance‐free material. However, deterioration of concrete structures has frequently been observed and documented in the last decades. The deterioration of concrete has several manifestations. A detailed description of damages observed on concrete is given by ACI 201.¹ One of the most common procedures followed, when there is indication of internal deterioration of concrete, is the removal of concrete cores from the structure for petrographic examination. The purpose of petrographic examination of concrete is to estimate and describe the condition and quality of concrete and its constituents, and to determine the causes of deterioration.^2,3 A wide range of material science techniques are available: visual techniques, porosimetry, chemical analysis, sonic techniques, spectroscopy, etc. The decision as to which of these techniques are selected for any particular job, is dictated by the nature of the problem. Most evaluations begin with a detailed microscopical examination, and proceed using other analytical techniques, based upon the results of the microscopical studies. The microscopical studies, by themselves, may be adequate for resolving the nature and particulars of the problem.³