Engineering Models of Masonry by Joint Repairing Techniques

When repointing historic masonry, it is the quality of the bond between mortar and stones that decides on the lifecycle of the structure. Once the composite system or the mortar start cracking, moisture can penetrate into the masonry and destroy the system. What mortar to use for what kind of masonry is normally an empirical decision. But in how far the mortar eventually selected is really suited for the purpose in question will not turn out until several years later. It is with this knowledge in mind that a simple engineering model has been developed, which is easy to use and which is to permit the likelihood of cracks to be assessed quantitatively. The model is based on calculations made for stresses occurring on the surface of the masonry and only requires a few material parameters. A combined, complex research model is being developed, which is to provide for exact structural analysis. For this model, the temperature and moisture transport is calculated with the aid of an FDM program. The temperature and moisture fields thus determined are then transferred to an FEM program which uses the material models of Rots (1997), Lourenco (1996) and Van Zijl (2000) for stress and deformation calculation. Keywords: FDM program, Masonry, Joint Repairing Techniques