Influences of electrolyte concentration on subcritical crack growth in sandstone in water

Nara, Yoshitaka; Nakabayashi, R.; Maruyama, Mihiro; Hiroyoshi, Naoki; Yoneda, Tetsuro; Kaneko, Katsuhiko

doi:10.1016/j.enggeo.2014.06.018

Cited by 45 publications

(22 citation statements)

References 44 publications

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“…The degree of salinity of pore fluids is known to affect the strength and fracture properties of rocks [ Risnes et al , ; Nara et al , ]. We have previously [ Rostom et al , ] found single calcite crystals to exhibit a higher fracture threshold in solutions of high ionic strength.…”

Section: Discussionmentioning

confidence: 99%

Repulsive hydration forces between calcite surfaces and their effect on the brittle strength of calcite‐bearing rocks

Røyne

Dalby

Hassenkam

2015

Geophysical Research Letters

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The long‐term mechanical strength of calcite‐bearing rocks is highly dependent on the presence and nature of pore fluids, and it has been suggested that the observed effects are due to changes in nanometer‐scale surface forces near fracture tips and grain contacts. In this letter, we present measurements of forces between two calcite surfaces in air and water‐glycol mixtures using the atomic force microscope. We show a time‐ and load‐dependent adhesion at low water concentrations and a strong repulsion in the presence of water, which is most likely due to hydration of the strongly hydrophilic calcite surfaces. We argue that this hydration repulsion can explain the commonly observed water‐induced decrease in strength in calcitic rocks and single calcite crystals. Furthermore, this relatively simple experimental setup may serve as a useful tool for analyzing surface forces in other mineral‐fluid combinations.

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Section: Discussionmentioning

confidence: 99%

Repulsive hydration forces between calcite surfaces and their effect on the brittle strength of calcite‐bearing rocks

Røyne

Dalby

Hassenkam

2015

Geophysical Research Letters

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“…This is known as subcritical crack growth, which is considered to be one of the main mechanisms responsible for the time-dependent behaviour of rock in the brittle regime (Atkinson, 1984). Most studies of subcritical crack growth in rock have been conducted on silicate rocks, such as igneous rocks Nara et al, 2009Nara et al, , 2010, sandstones (Holder et al, 2001;Ponson, 2009;Nara et al, 2011Nara et al, , 2014, and novaculite (Atkinson, 1980).…”

Section: Introductionmentioning

confidence: 99%

Influence of surrounding environment on subcritical crack growth in marble

et al. 2017

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a b s t r a c tUnderstanding subcritical crack growth in rock is essential for determining appropriate measures to ensure the long-term integrity of rock masses surrounding structures and for construction from rock material. In this study, subcritical crack growth in marble was investigated experimentally, focusing on the influence of the surrounding environment on the relationship between the crack velocity and stress intensity factor. The crack velocity increased with increasing temperature and/or relative humidity. In all cases, the crack velocity increased with increasing stress intensity factor. However, for Carrara marble (CM) in air, we observed a region in which the crack velocity still increased with temperature, but the increase in the crack velocity with increasing stress intensity factor was not significant. This is similar to Region II of subcritical crack growth observed in glass in air. Region II in glass is controlled by mass transport to the crack tip. In the case of rock, the transport of water to the crack tip is important. In general, Region II is not observed for subcritical crack growth in rock materials, because rocks contain water. Because the porosity of CM is very low, the amount of water contained in the marble is also very small. Therefore, our results imply that we observed Region II in CM. Because the crack velocity increased in both water and air with increasing temperature and humidity, we concluded that dry conditions at low temperature are desirable for the long-term integrity of a carbonate rock mass. Additionally, mass transport to the crack tip is an important process for subcritical crack growth in rock with low porosity.

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“…Repulsive forces between calcite crystals, caused by water adsorption or the electric double layer (Nara et al, 2014;Røyne et al, 2015), should be sensitive to the ionic strength of the solution. Specifically, increasing ionic strength is expected to decrease the repulsion between the grains and this is expected to result in a lower frequency of grain detachment events.…”

Section: Resultsmentioning

confidence: 99%

“…This process could weaken carbonate rocks. These repulsive forces are likely to be related to water adsorption on the crystal surfaces or to the electric double layer (Nara et al, 2014;Røyne et al, 2015) but in both cases, decreasing the concentration of dissolved ions is expected to increase the degree of repulsion. Such intergranular repulsion could be an important factor in calcite grain detachment from the surface of rocks during weathering, but whether or not repulsive forces do in fact shape reacting rock surfaces has yet to be determined.…”

Section: Introductionmentioning

confidence: 99%

Repulsion between calcite crystals and grain detachment during water–rock interaction

Levenson¹,

Emmanuel²

2017

Geochem. Persp. Let.

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doi: 10.7185/geochemlet.1714 Weathering in carbonate rocks is often thought to be governed by chemical dissolution. However, recent studies have shown that mechanical detachment of tiny grains contributes significantly to the overall surface retreat. Whether this detachment is caused by shear forces acting at the surface, or repulsive forces acting between grains, was not known. In this study, we used atomic force microscopy to examine the mechanism of grain detachment and we demonstrate that it occurs even in the absence of shearing fluid flow. This suggests that the removal of grains from rock surfaces can be caused by repulsive forces between calcite grains. Although these repulsive forces are expected to be sensitive to the ionic strength of the solution, we did not find enough evidence to demonstrate a correlation between salinity and the frequency of grain detachment. Importantly, our findings suggest that grain detachment occurs during water-rock interaction under low flow conditions over a range of salinities, with potential impacts on geological carbon sequestration and enhanced oil recovery in carbonate formations.

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Influences of electrolyte concentration on subcritical crack growth in sandstone in water

Cited by 45 publications

References 44 publications

Repulsive hydration forces between calcite surfaces and their effect on the brittle strength of calcite‐bearing rocks

Repulsive hydration forces between calcite surfaces and their effect on the brittle strength of calcite‐bearing rocks

Influence of surrounding environment on subcritical crack growth in marble

Repulsion between calcite crystals and grain detachment during water–rock interaction

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