The role of properties on the decay susceptibility and conservation issues of soft limestones: Contribution of Ançã stone (Portugal)

Soft limestones are widely present in noteworthy constructions, but they are prone to decay due to their specific characteristics. In this paper, soft Ançã stone possessing a wide range of properties are analyzed to explain the degradation patterns and degradation rates that can be found in monuments and to estimate decay susceptibility. Experimental results indicated good correlations between physical, hydric and mechanical properties, allowing to propose drilling resistance and shore hardness as the key to estimate several other properties of soft limestones in-situ. Integrity loss rate of soft limestones submitted to freeze-thaw cycles, was found to be closely related to the saturation coefficient. Analytic relation to estimate decay of soft limestones and number of freeze-thaw cycles required to reach a pre-collapse state are drawn.