NDE ultrasonic methods to characterise the porosity of mortar

Premature damage of mortar and concrete structures, due to environmental action, demands procedures to estimate durability of this type of components. Mortar or concrete composition (e.g. grain size, type and percentage of sand) may have some influence in the durability, but it is mainly related to porosity, which determines the interaction between aggressive agents and material. In this work, several DDE ultrasonic methods to estimate porosity of mortar are presented and evaluated. In these methods, porosity is related to (1) the material structural noise, (2) sound velocity and (3) ultrasonic attenuation. In all these methods, mortar is consider to be formed by only two phases: solid and pores. (C) 2001 Elsevier Science Ltd. All rights reserved.