Influence of the salt crystallization in the durability of granites used in vernacular masonry buildings

Martins, Lurdes; Vasconcelos, Graça; Lourénço, Paulo B.; Palha, Carlos Alberto Oliveira Fernandes

doi:10.1201/b21889-63

Cited by 4 publications

(2 citation statements)

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“…The low UCS and BTS values of fresh Va-G was attributed to its higher effective porosity, higher Texture (crystal size and orientation) and mineralogical composition play an important role when it comes to stone weathering. Martins et al (2016) expressed that coarse and Sh-M prior to and after the aging test and e, f distribution of microcracks length of Va-G and Sh-M pre-and post-aging test, respectively. Note that the length and width of microcracks were measured in millimeters (mm) and micrometers (μm), respectively granites are more prone to decay by the salt crystallization.…”

Section: Discussionmentioning

confidence: 99%

Artificial microcracking of granites subjected to salt crystallization aging test

Zalooli

Khamehchiyan

Nikudel

et al. 2020

Bull Eng Geol Environ

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Salt crystallization-induced decay of Vardavard granodiorite and Shirkouh monzogranite, two Iranian building stones, were assessed with two non-destructive methods: saturation-buoyancy technique and P-and S-wave velocity measurement. Moreover, polarized and fluorescence microscopy studies were used to evaluate the behavior of the studied stones at microscopic scale against a salt crystallization aging test. The aging test extended pre-existing microcracks and generated new ones. Intracrystalline microcracking was the most predominant microcrack type for both samples. Fine-grained Vardavard granodiorite experienced higher intercrystalline microcracking than coarse-grained Shirkouh monzogranite. The microcracking mechanism of feldspars substantially depends on their alteration degree and microstructural precursors. When a growing microcrack reaches a biotite, it propagates within the crystal if the growing microcrack coincides with the cleavage plane; otherwise, it propagates as an intercrystalline one. The increase in maximum microcrack length of the samples was higher than the increase in their mean microcrack length. Low-strength Vardavard granodiorite showed higher microcrack width after the aging test. Dry weight loss in low-strength Vardavard granodiorite was more pronounced than in high-strength Shirkouh monzogranite. Dry unit weight decreased at a higher rate than saturated unit weight with the increase of effective porosity. The reduction in ultrasonic wave velocities and the increment in effective porosity and water absorption were more pronounced for Vardavard granodiorite, indicating a higher degree of decay, i.e., higher microcrack generation, enlargement, and widening. Shirkouh monzogranite, which has large-sized crystals and pores, wider initial microcracks, high tensile strength, and low effective porosity and microcrack density, was more durable than Vardavard granodiorite.

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Section: Discussionmentioning

confidence: 99%

Artificial microcracking of granites subjected to salt crystallization aging test

Zalooli

Khamehchiyan

Nikudel

et al. 2020

Bull Eng Geol Environ

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“…Laboratory studies are, in general, more frequent than field studies (around 50% more), with diverse types of salts and weathering conditions (for recent reviews on laboratory salt weathering testing see Alves et al [5], Lubelli et al [6]). In the selected set, the main rock types are volcanic rocks (Seiki et al [3]; Yu & Oguchi [7]; Yavuz [8]; López-Doncel et al [9]; Germinario et al [10]; Özşen et al [11]; Çelik & Aygün [12]; Martínez-Martínez et al [13]; Pötzl et al [14]; Sato & Hattanji [15]; Zalooli et al [16]), being dominated by studies of pyroclastic rocks, and plutonic rocks (Cámara et al [4]; Yu & Oguchi [7]; López-Arce et al [17]; Silva et al [18]; Vázquez et al [19]; Cerrillo et al [20]; Martins et al [21]; Sousa et al [22]; Vázquez-Nion et al [23]; Graus et al [24]) with granite being dominant in this subset. In our present review we found fewer publications concerning laboratory testing of metamorphic rocks; most of them studying marbles (Vázquez et al [19]; Martínez-Martínez et al [25]; Navarro et al [26]; Vazquez et al [27]) with one studying gneiss (Ricardo et al [28]) but none in slates or schists.…”

Section: Analysis Of Publicationsmentioning

confidence: 99%

Approaches to the Study of Salt Weathering of Geological Materials

Alves

Figueiredo

2019

The 2nd International Electronic Conference on Geosciences

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Salt weathering is the main erosive process affecting diverse geological materials in historical and contemporary structures and can also contribute to visual changes by surface crystallization. The main goal of the present paper is to assess publications concerning the study of salt weathering of natural stone considering the main approaches (laboratory tests and field observations). Our focus will be on rock types other than sedimentary carbonate rocks and sandstones (which are the most studied rocks both in laboratory and field studies). Granite and pyroclastic rocks are dominant in the studied set. Also deserves highlighting (for scientific reasons) the scarcity of studies regarding foliated rocks and marble.

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