Hydraulic lime mortar in the ambit of stone restoration: evaluation of applicability

This study presents the results of the applicability of hydraulic lime mortars in the ambit of stone conserva- tion and restoration. Historical buildings, as well as sculptures or ornamental artworks exposed to environmental influences, composed by natural stone materials suffer severe alteration/degradation in the course of time. On this account, the physico- chemical properties of hydraulic lime mortars have been compared with those of two calcarenitic rocks (Barxeta and Bateig azul), found in historical Valencian monuments. A systematically analytical procedural method was established on a series of test specimens in order to prove compatibility/ replaceability of limestones. The specimens were subjected to standard accelerated physical-chemical ageing tests. Compressive and flexural strength tests have been performed on the mortars and the stone material in order to determine the physical degra- dation. Alteration by chemical attack was simulated by the exposure in a SO 2 pollutant chamber and salt crystallisation test. The experiments performed show that the applied mortars have on one hand similar physical resistance and on the other hand present higher chemical resistance properties, especially against salt crystallisation in comparison to the natural stones and therefore might be of special interest for replicas.

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