Water Saturation Induced Changes in the Indirect (Brazilian) Tensile Strength and the Failure Mode of Some Igneous Rock Materials

Abstract

The present study concentrates on water induced strength reduction and variation of the failure mode in indirect (Brazilian) tension tests of several igneous rock materials under three moisture cases of ovendry, air-dry and fully saturated states. In this respect, two andesite and three tuff materials which contain no visible flaws were subjected to indirect tensile strength tests using the Brazilian disc method. Once the tension tests were carried out, photographs of the broken samples were taken to investigate the changes in the failure mode. As a result, it was found that tensile strengths of the samples were highly reduced with the presence of the water and the natural humidity. Additionally, it has been deduced that the failure mode of the samples mainly shifts to central fracturing with the presence of natural moisture and saturation. Although the central crack is the ideal type for the theory of Brazilian tensile strength determination, indefinite contact properties like contact angle and frictions are some notable issues to make only considering failure shapes for the validity of the test results misleading.

The tensile strength of volcanic rocks: Experiments and models

“…Other differences between the numerical samples and natural samples include (1) the numerical samples have a uniform pore size (Figure 1), which is not the case for natural samples (Figure 2), (2) the pores in our numerical samples are either circular or elliptical (Figure 1), whereas pores in natural samples can be oddly shaped (Figure 2), (3) volcanic rocks typically contain microcracks (Figure 2), which are not present in the numerical samples (Figure 1), and (4) all of the porosity in our numerical samples is isolated (Figure 1), whereas natural volcanic rocks can contain pores that are connected by other pores, pore throats, and microcracks; Figure 2). (2012), Wedekind et al (2013), Karakuş and Akatay (2013), Hashiba and Fakui (2015), Siratovich et al (2015), Fener and Ince (2015), Ündül and Er (2017), Yavuz et al (2017), Lamb et al (2017), Malik et al (2017), Aldeeky and Hattamleh (2018), Zorn et al (2018), Hornby et al (2019), Harnett et al (2019), Moon and Yang (2000), Yasar and Komurlu (2020), and Kendrick et al (2021).…”

The mechanical behaviour and failure modes of volcanic rocks: a review

“…Fig.25Tensile strength as a function of porosity for volcanic rocks (n = 277; these data are provided in a Microsoft Excel© spreadsheet that accompanies this contribution as Supplementary Material). Data from:Tuğrul and Gürpinar (1997), Gupta and Rao (2000), Chen et al (2004), Ersoy and Atici (2007), Kılıç and Teymen (2008), Nara et al (2010b), Kahraman and Yeken (2010), Graue et al (2011), Lavallée et al (2012a), Heap et al (2012), Wedekind et al (2013), Karakuş and Akatay (2013), Hashiba and Fukui (2015), Siratovich et al (2015), Fener and Ince (2015), Ündül and Er (2017), Yavuz et al (2017), Lamb et al (2017), Malik et al (2017), Aldeeky and Al Hattamleh (2018), Zorn et al (2018), Hornby et al (2019), Harnett et al (2019),Moon and Yang (2020),Yasar and Komurlu (2020),Kendrick et al (2021) …”