Porosity estimation of concrete by ultrasonic NDE

The increasing number of concrete structures with symptoms of premature det erioration due to environmental action demands procedures to estimate the d urability of this type of component. Concrete durability is related to poro sity, which determines the intensity of interactions of the material with a ggressive agents. The pores and capillaries inside the structure facilitate the destructive processes that generally begin in the surface. In this work, an ultrasonic NDE technique to estimate the porosity of concr ete is developed. The method is based on the analysis of the mechanical beh aviour of mortar probes built with calibrated sand, in which the concentrat ion of water-cement mixture has been varied. In this sense, data of sound v elocity are correlated with data of porosity, which have been previously me asured by destructive measurements. (C) 2000 Elsevier Science B.V. All righ ts reserved.