Compatibility assessment for repair mortars: case study concerning an optimized cement-based mix on Tuffeau de Lincent

Mortars developed for the reconstitution and plastic repair of natural stones have become increasingly more popular. They make a good alternative for the replacement of deteriorated stones, since they are capable of preserving the (memory of) diversity in building materials. In this article, the ‘compatibility’ of repair mortars is discussed and the various approaches towards these compatible repair mortars are briefly described. This research continues earlier research for a repointing mortar for the Tuffeau de Lincent, a friable stone in need for restoration and replacement. At the Hc Tech Lab (University of Mons), this repointing mortar was developed using an auto-formulation tool, based on resistance and color compatibility. In this article, the repointing mortar was taken further and tested and compared with the natural stone, in order to assess its use as plastic repair mortar for the Tuffeau de Lincent stone. The results of this research are presented in this article, including density, porosity and local strength tests. The pore size distribution and connectivity was established through mercury porosimetry and micro-CT techniques. The analysis outlines encouraging results for the further development of the tool and could be considered as a preliminary approach for assessing the compatibility of a repair mortar for natural stone