Evaluation of stone durability using a combination of ultrasound, mechanical and accelerated aging tests

Abstract

The durability of a rock when exposed to decay agents is an important criterion when assessing its quality as a building material. Our study focuses on six varieties of natural stone (two limestones, one dolostone, one travertine and two sandstones) that are widely used in both new and historical buildings. In order to assess their quality, we measured and characterized their dynamic elastic properties using ultrasounds, we measured their compressive strength using the uniaxial compression test and we evaluated their durability by means of accelerated aging tests (freeze-thaw and salt crystallization). In order to get a full picture of the decay suffered by the different stones, we determined the composition and amount of the clay fraction of the six stones. We also observed small fragments subjected to the salt crystallization test under an environmental scanning electron microscope to study any textural change and measured the changes of colour on the surface with a spectrophotometer. Finally, we analysed the pore system of the stones before and after their deterioration using mercury injection porosimetry. We then compared the results for the different stones and found that dolostone obtained the best results, while the two limestones proved to be the least durable and had the lowest compressive strength.

El material pétreo en un edificio monumental de la costa Tirrenica (Italia): nuevos datos sobre la relación entre propiedades pètreas y análisis estructural

“…Moreover the lower parts (points A) are more affected by decay than the higher ones (points B). The higher the ultrasonic pulse velocity, the higher the uniaxial compressive strength as obtained by many authors (Molina et al 2013) and viceversa. Pignatelli sandstone (PS) shows average resistance values similar to the quarry samples (AF).…”

Colmenar Limestone, Madrid, Spain: considerations for its nomination as a Global Heritage Stone Resource due to its long term durability

“…Variations in ultrasound velocity are a good indicator of rock quality and a technique for monitoring the changes taking place during decay (Barbera et al 2012;Martinez-Martinez et al 2013;Molina et al 2013). In all the trials, the general trend was a decline in ultrasound velocity.…”

A review of the nature, role and control of lithobionts on stone cultural heritage: weighing-up and managing biodeterioration and bioprotection

“…Biodeteriorative and bioprotective processes may or may not balance out, and thus produce complex impacts on the intrinsic stone properties relevant for durability, which can be defined as the capacity of a building material to maintain its size, shape, strength and aesthetic appearance over time (Bell 1993). In particular, knowledge of lithobiont-rock interactions should be combined with quantitative investigation of their impacts on petrophysical properties, including porosity, presence of swelling clay minerals, compactness, water absorption, presence and distribution of anisotropies, compressive strength, and surface hardness (Molina et al 2013;Wilhelm et al 2016).…”