Heat and Moisture Simulations of Repair Mortars: Benchmark Experiments and Practical Cases in Conservation

Simulation tools are increasingly used for assessment and design of buildings, for new construction as well as for historical buildings. HAM (heat, air and moisture) simulations of porous materials can be very useful to assess the behaviour of repair mortars because hygrothermal conditions govern many decay mechanisms and are one of the keys to compatibility. This paper demonstrates some of the possibilities for mortars in a number of practical cases, using Delphin as a HAM simulation code. The first is a 2D assessment of the hygric interaction between mortar and brick. Next there are a series of 1D simulations of multi-layered porous systems. Pragmatic methods to obtain the necessary material parameters are proposed. Issues like local alterations of transport properties and interface resistances are briefly discussed. The possibilities of simulations of the behaviour of salt solutions are introduced. In a last case, a procedure to assess the risk on frost damage is demonstrated. Finally some possible or desirable future developments are pointed out: incorporating climate change, combining HAM with other simulation methods and stochastic treatment of material parameters.