Formulation and microstructural evaluation of tuff repair mortar

The purpose of this study was to develop a compatible repair mortar for two lithotypes of Peračica tuff (Slovenia): fine-grained and coarse-grained. Mineralogical–petrographic characterization of tuff was carried out via optical microscopy and X-ray powder diffraction, and the relevant physical–mechanical properties of tuff and repair mortars were determined: capillary water absorption, water absorption at atmospheric pressure, open porosity, compressive strength and resistance to salt crystallization. A repair mortar was prepared by mixing crushed Peračica tuff and quartz sand, with different grain size and mass ratios, and ethyl silicate (KSE 500 STE, Remmers) as a binder. The results showed that with an appropriate combination of crushed tuff, quartz sand and ethyl silicate, a compatible repair mortars can be obtained for both lithotypes.