Accelerated aging laboratory tests for the evaluation of the durability of hydrophobic treated and untreated andesite with respect to salt crystallization, freezing–thawing, and thermal shock

The present work reviews studies with information on the effects of water by itself on stones of the built environment both to assess the impact of this substance and to discuss possible implications for conservation. The analysis concerns empirical results from previous publications dealing with the effects, on several rock types, of freeze–thaw, wetting, erosion by running water and substances resulting from the water–stone interaction. Laboratory studies have shown that water freezing can cause physical damage even in low porosity rocks. As far as we know, this is the first review that considers comparative laboratory studies of freeze–thaw and salt crystallization on the same rock specimens, and these point to lower erosive effects than salt weathering, as freeze–thaw can provoke catastrophic cracking. Wetting has shown strong damaging effects on some fine-grained clastic rocks. Erosive features have been reported for rain exposition and for some fountain settings albeit, in these field studies, it could be difficult to assess the contribution of pollutants transported by water (this assessment could have meaningful implications for stone conservation, especially in fountain settings). Water also interacts with stone constituents, namely sulfides and soluble salts, releasing substances that could impact those stones. Sulfides are a relatively frequent issue for slates and granites, and our observations suggest that for this last rock type, this issue is mostly associated with the presence of enclaves and, hence, avoiding the surface exposition of such enclaves could solve the problem.

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“…Çelik and Sert [40] Lavic rock Low mass loss in each case (below 1.0%) but results for sodium sulfate were around 8 times higher.…”

Section: Germinario and Török [21] Pyroclastic Rocksmentioning

confidence: 84%

Effects of Water on Natural Stone in the Built Environment—A Review

et al. 2021

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“…The resistance of stone to salt crystallization was evaluated following the procedure described in the standard UNI EN 12370:2001 [ 72 ], which is adopted for stones with a porosity greater than 5%. These achievements, frequently coupled with other accelerated aging tests (e.g., cyclic freezing–thawing) are widely used methods to estimate the extent of damage suffered by stony materials when exposed to decay agents and the general durability of natural stones [ 73 , 74 , 75 , 76 ]. In particular, salts growing in porous hosts represent a major source of decay for natural building stones; therefore, a lot of research has been devoted to this topic [ 50 , 77 , 78 , 79 , 80 , 81 , 82 ].…”

Section: Methodsmentioning

confidence: 99%

Comparison of Latest and Innovative Silica-Based Consolidants for Volcanic Stones

2021

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This research explores the new perspectives in conservation and protection of two macroporous tuff stones, widely employed in the architectural heritage of Campania region, characterized by highly heterogeneous rock fabric and texture and a variable mineralogical composition that represent crucial factors responsible for their weak durability. The consolidation treatments were performed with a recently and widely used suspension of nano-silica crystals in water and with a lithium silicate solution that has received up to now scarce attention as a consolidant agent. Physical investigations (open porosity, Hg porosimetry, water absorption), morphological observations (SEM analyses) and visual appearance test (colorimetric measurements), along with assessments of performance indicators such as ultrasonic pulse velocity, surface cohesion test (peeling test) and durability test (salt crystallization), were carried out to investigate the consolidation effectiveness. Overall, lithium silicate consolidant showed a better behavior in terms of superficial cohesion, a most successful strengthening action and a considerable enhancement of salt resistance.

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“…The purpose of these tests is to determine how the building stone will perform in a specific environmental condition or to evaluate the effectiveness of a protective treatment in preventing deterioration. Frost resistance, salt crystallisation resistance and thermal shock ageing resistance are the most frequent tests used to assess the durability of natural stones [20]. However, other tests such as resistance to SO 2 ageing, wetting-drying cycles and salt mist ageing resistance are widely used.…”

Section: Direct Determination Of Durability By Ageing Testsmentioning

confidence: 99%

“…The mechanical properties determined were: uniaxial compressive strength (EN 1926) [60] and flexural strength under concentrated load (EN 12372) [61]. Twenty (20) specimens were used in each of these tests. For uniaxial compressive strength, the specimens were cubes (50 × 50 × 50 mm), while for flexural strength, specimens with dimensions 180 × 60 × 30 mm were used.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Effect of Salt Mist Ageing on the Physical and Mechanical Properties of Two Ignimbrites from the Canary Islands (Spain)

Valido,

Cáceres,

Freire-Lista

et al. 2023

Materials

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The aim of this research work is to study the effect of salt mist ageing on the physico-mechanical properties of two ignimbrites from the Canary Islands (Spain). Due to their insular nature and extensive coastlines, these regions are highly susceptible to atmospheric salt aerosols, which is a significant weathering agent for building materials. The ignimbrites analysed are marketed under the names “Azul Lomo Tomás de León” and “Marrón de Abades” and are widely used as building stones. Petrographic, mineralogical and chemical properties were obtained via polarisation microscopy, X-ray diffraction and X-ray fluorescence. The samples were subjected to 60 cycles of a salt mist environment, following relevant European standards. Scanning electron microscopy images of the specimens were analysed along with physical properties, including apparent density, open porosity, water absorption, colourimetry and ultrasound propagation velocity, initially and after every 20 cycles, allowing us to assess their evolution during the ageing test. Mechanical properties were evaluated using uniaxial compressive strength and flexural strength under concentrated load tests on two groups of specimens: one unaged and the other subjected to 60 ageing cycles. With the exception of apparent density, the other properties show a decrease between 5% and 30%. However, open porosity increases and is one of the properties most affected by the ageing test.

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Accelerated aging laboratory tests for the evaluation of the durability of hydrophobic treated and untreated andesite with respect to salt crystallization, freezing–thawing, and thermal shock

Cited by 26 publications

References 44 publications

Effects of Water on Natural Stone in the Built Environment—A Review

Effects of Water on Natural Stone in the Built Environment—A Review

Comparison of Latest and Innovative Silica-Based Consolidants for Volcanic Stones

Effect of Salt Mist Ageing on the Physical and Mechanical Properties of Two Ignimbrites from the Canary Islands (Spain)

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