Numerical study of humidity flux in historical mortars based in air lime mortar: Simulation and a case study

The structural safety of historical buildings often requires advanced structural analysis. Mortar typically exhibits complex composition and structural behavior. In different parts of the world, there is a significant number of historical constructions based on lime mortar. The moisture content in lime structures has a significant influence on their behavior and performance. Experimental results from a mortar monitoring program developed by the team involved in this study were used as a reference. To simulate this drying process, a software implemented in the Finite Difference Method is utilized (FDM). The software was employed to identify the key material parameters (D1 e f (boundary)), that best fit the experimental data, considering the approach presented by the Model Code 2010. The modeling strategy was initially applied to the experimental results of cylindrical specimens and subsequently to the experimental results of a prismatic mold. Overall, the model was able to fit satisfactorily. When compare the results with values for concrete, higher values were found for diffusivity and boundary coefficient. For the studied specimens, both experimental and numerical results indicated a reduced moisture gradient. These findings are associated with high porosity. Subsequently, considering the obtained parameter values, a structure simulating a real historic construction is analyzed. The results show that the humidity inside the inner parts remains elevated for long periods (similar to 100 years).