Advanced Material Technology for the Conservation of Historical Buildings

Four different compositions were designed for restoration mortars reflecting the dominant ancient and historical types. Three of them (two lime and one hydraulic lime mortar) contained a pozzolanic member while the two of them (lime and hydraulic lime mortar) contained polypropylene fibers. Micro-morphological and elemental (SEM/EDAX), mineralogical (XRD) and thermal analysis (TGA) were performed in order to identify the microstructure, the chemical consistency, and durability of each composition. Although hydraulic lime presented a slightly better response on mechanical strength, lime mortar with pozzolan and polypropylene fibers selected, in terms of cost factor, as a sufficient composition for further research. Meeting the requirements for materials under the triptych of “compatibility-coherence-reversibility” with the authentic ancient matrix as well as resistant to climate changes, metakaolin was used as an improvement agent in the binder part at 25% replacement. The experimental mortar (ΕΜ) updated its characteristics in both mechanical and hydraulic aspects. Crystallization test, elevated humidity conditions, acid rain, freeze-thaw tests were performed under simulated conditions with respect to international standards. EM mortar responded adequately to extreme climatic conditions in contrast to the standard lime mortar. That attributed to the ability of metakaolin to resist in contraction-expansion processes by maintaining its matrix.