Study and characterization of stone mortars used as a volumetric reconstruction material in conservation-restoration of monumental heritage

Abstract

This paper is focused on the evaluation of different repair mortars used for volumetric reconstruction in Monumental Heritage. The research purpose is to analyze and understand degradation processes, to study the compatibility with the original litotype and to make predictions about the durability of the material and in order to evaluate their suitability. Here, a series of specimens with different mortars and binders have been prepared: a mortar of lime in paste (Unicmall, and sand), a mortar of powder lime (Cumen) and two mortars with hydraulic binders (Parrot and Petratex). In the same way, a series of normalized physical (mechanical)-chemical tests have been performed. For the characterization of materials has been used SEM/EDX and electromechanical twin-screw machine. The results of the tests have been compared with a calcarenitic bioclast stone from the quarry of Hellí­n (Albacete) and the intrinsic properties of these materials and their behavior in environmental conditions have been determined. All tested mortars offered satisfactory results for restoration purposes and can be used as a material of structural and ornamental reconstruction, proved by the good compatibility with the natural stone and the durability test results. The best results with regard to the natural stone have been obtained with the hydraulic binder Petratex.