NDE ultrasonic methods to characterise the porosity of mortar

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