Determination of the Water Content in the Porous Structure of Mortar By Means Of Micromechanical Models and Ultrasonic Velocity

The application of cementicios materials is widely extended fundamentally for its use as structural elements. In this sense, it presents some advantages respect to other materials, in spite of the different physical and chemical attacks that limit its durability. This durability is a function of its porous structure, because the existence of pores facilitates the destructive agents which attack the interior of the material. These agents frequently are transported dissolved in water and therefore he is advisable to determine the presence of this element in the porous structure by means of non destructive techniques. In this work we are going to evaluate the amount of present water in mortar samples from the ultrasonic velocity and multiphasic micromechanical models. Introduction The behaviour of concrete structures throughout their useful lifetime is one of the main subjects under study and investigation in civil engineering. Durability of said structures will depend on factors such as chemical attack, the mechanical load to which they are subjected, temperature variations and drying and wetting processes, amongst others. The scope of the damage produced by the above-outlined factors will mainly arise due to the materials’ microstructural characteristics. Microstructural characteristics depend to properties of the constituting materials, dosage, manufacturing process, maturity, etc. The porous structure of the cementitious materials is one of the main microstructural characteristics, due to the fact that it is responsible for transporting the substances into the concrete structure. The porous structure is formed by an extensive network of interconnected pores that cover sizes ranging from nanometres to millimetres, which may be partially or totally full of fluids. One of the fluids that in general is present in said structures is water, which, depending on the environment in which the concrete structure is situated, may cause damage due to freeze – thaw cycles, diffusion processes and drying process, amongst others. In general, the above-mentioned factors are presented in coupled fashion with each other, which makes application of models providing global information covering durability of cementitious materials very complex. The purpose of this paper will be the evaluation of the behaviour of the ultrasonic velocity of the cement-based materials when the water content in the ECNDT 2006 Poster 141