Effect of water saturation on uniaxial compressive strength and damage degree of clay-bearing sandstone under freeze-thaw

2019 ◽  
Vol 79 (4) ◽  
pp. 2021-2036 ◽  
Author(s):  
Yanzhang Liu ◽  
Yuantian Cai ◽  
Shibing Huang ◽  
Yunlin Guo ◽  
Guofeng Liu
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Water Saturation ◽  
Freeze Thaw ◽  
Effect Of Water ◽  
Damage Degree

scholarly journals Degradation of Mechanical Behavior of Sandstone under Freeze-Thaw Conditions with Different Low Temperatures

2021 ◽  
Vol 11 (22) ◽  
pp. 10653
Author(s):  
Jingwei Gao ◽  
Chao Xu ◽  
Yan Xi ◽  
Lifeng Fan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Uniaxial Compressive Strength ◽  
Dynamic Strength ◽  
Freezing Temperature ◽  
P Wave ◽  
Freeze Thaw ◽  
P Wave Velocity

This study investigated the effects of freezing temperature under freeze-thaw cycling conditions on the mechanical behavior of sandstone. First, the sandstone specimens were subjected to 10-time freeze-thaw cycling treatments at different freezing temperatures (−20, −40, −50, and −60 °C). Subsequently, a series of density, ultrasonic wave, and static and dynamic mechanical behavior tests were carried out. Finally, the effects of freezing temperature on the density, P-wave velocity, stress–strain curves, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption of sandstone were discussed. The results show that the density slightly decreases as temperature decreases, approximately by 1.0% at −60 °C compared with that at 20 °C. The P-wave velocity, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption obviously decrease. As freezing temperature decreases from 20 to −60 °C, the static uniaxial compressive strength, static elastic modulus, dynamic strength, and dynamic energy absorption of sandstone decrease by 16.8%, 21.2%, 30.8%, and 30.7%, respectively. The dynamic mechanical behavior is more sensitive to the freezing temperature during freeze-thawing cycling compared with the static mechanical behavior. In addition, a higher strain rate can induce a higher dynamic strength and energy absorption.

scholarly journals Strength and abrasive properties of andesite: relationships between strength parameters measured on cylindrical test specimens and micro-Deval values—a tool for durability assessment

2020 ◽  
Author(s):  
Balázs Czinder ◽  
Ákos Török
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Test Results ◽  
Strength Parameters ◽  
Data Set ◽  
Freeze Thaw ◽  
Laboratory Test Results ◽  
Significant Difference ◽  
Abrasive Properties ◽  
Water Saturated

Abstract Aggregates are necessary materials for the construction industry. Owing to their favourable properties, andesites are frequently used rock materials; hence, the investigation of their mechanical and aggregate properties has great significance. This paper introduces the analyses of 13 Hungarian andesite lithotypes. The samples were collected from six andesite quarries in Hungary. Cylindrical specimens and aggregate samples with 10.0/14.0-mm-sized grains were made from rock blocks. The specimens were tested in dry, water-saturated and freeze–thaw subjected conditions. Bulk density, uniaxial compressive strength, modulus of elasticity, indirect tensile strength and water absorption were measured. The abrasion resistance was tested by micro-Deval tests. The flakiness indexes of the samples were also measured. The data set of the laboratory test results provided input for further, one- and two-variable statistical analyses. According to the test results, there is no significant difference between the strength parameters measured in water-saturated and in freeze–thaw subjected conditions. The correlation and regression analyses revealed relationships between some rock mechanical parameters, as well as between micro-Deval coefficient and uniaxial compressive strength.

scholarly journals Influence of the Size and Type of Pores on Brick Resistance to Freeze-Thaw Cycles

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3717
Author(s):  
Ivanka Netinger Grubeša ◽  
Martina Vračević ◽  
Vilma Ducman ◽  
Berislav Marković ◽  
Imre Szenti ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Frost Resistance ◽  
Mercury Porosimetry ◽  
Micro Ct ◽  
Freeze Thaw ◽  
Damage Degree ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Overall Resistance ◽  
Open Versus

This paper estimates the frost resistance of bricks using the ratio of compressive strength before freezing to compressive strength after freezing to describe the damage degree of bricks being exposed to freeze-thaw cycles. In an effort to find the ratio that clearly distinguishes resistant bricks from non-resistant bricks, the authors attempted to establish the correlation between the ratio and Maage factor as a recognized model for assessing brick resistance. To clarify the degree of damage of individual bricks, the pore size distribution has been investigated by means of mercury porosimetry. Additionally, micro computed X-ray tomography (micro-CT) has been employed to define the influence of the type of pores (open or closed) and their connectivity on the frost resistance of bricks. According to the results, it can be concluded that there is a good correlation between the Maage factor and the ratio of pre- to post-freeze-thaw cycle compressive strengths, and that the latter ratio strongly correlates with the percentage of large pores (≥3 mm) in the brick. If such a correlation could be confirmed in a larger sample, then the ratio of pre- to post-freeze-thaw cycle compressive strengths could be used as a new method for assessing brick resistance to freeze-thaw cycles and it would be possible to determine the minimum percentage of large pores required to ensure the overall resistance of brick to freeze-thaw conditions. The complexity of the problem is, however, evidenced by the fact that no clear connection between the type (open versus closed) or connectivity of pores and the frost resistance of bricks could be revealed by micro-CT.

scholarly journals Influence of Water Content on the Mechanical Parameters of the Intact Rock and Rock Mass

2018 ◽  
Author(s):  
Balázs Vásárhelyi ◽  
Morteza Davarpanah
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Rock Mass ◽  
Internal Friction ◽  
Water Content ◽  
Uniaxial Compressive Strength ◽  
Water Saturation ◽  
Friction Angle ◽  
Intact Rock ◽  
Mechanical Parameters

The goal of this paper is to present the influence of the water saturation of the intact rock on different mechanical parameters, such as internal friction angle, cohesion, Hoek-Brown constant (mi ). Analyzing the previously published results, it was found that due to water saturation both the uniaxial compressive strength and tensile strength decrease similarly, i.e. the ratio of these two values is constant, thus the internal friction angle does not change but only the cohesion. Likewise, Hoek-Brown constant (mi ) remains constant; it is independent on the moisture content.The ratio of the elastic modulus and the uniaxial compressive strength of the intact rock is also calculated. According to the laboratory results, this ratio (namely modulus ratio) is also independent on the water content.It is shown that the mechanical parameters of the rock mass (such as compressive strength, tensile strength, deformation modulus) similarly depend on the water content than the intact rock.

scholarly journals Variations on Reservoir Parameters of Oil Shale Deposits under Periodic Freeze-Thaw Cycles: Laboratory Tests

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Rui-heng Li ◽  
Zhong-guang Sun ◽  
Jiang-fu He ◽  
Zhi-wei Liao ◽  
Lei Li ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Longitudinal Wave ◽  
Uniaxial Compressive Strength ◽  
Wave Velocity ◽  
Oil Shale ◽  
Longitudinal Wave Velocity ◽  
Freeze Thaw ◽  
Frozen Wall

As one of the most important unconventional hydrocarbon resources, the oil shale has been extracted with a frozen wall to successfully increase the shale oil production and reduce environmental pollution, which results from the harmful liquids in the in situ conversion processing of oil shale. Thereby, the strength and permeability of the frozen wall are extremely critical to reduce the harmful chemicals leaching into the groundwater. However, the permeability and strength of the frozen wall can be influenced by periodic freeze-thaw cycles. In order to investigate the damage and deterioration characteristics of oil shale samples after various periodic freeze-thaw cycles, the oil shale samples were periodically frozen and thawed as many as 48 times, after which the sample mass, stress-strain, freeze-thaw coefficient, uniaxial compressive strength, elastic modulus, and longitudinal wave velocity of the oil shale samples were separately measured. According to the measured results, the number of freeze-thaw cycles greatly influenced the physical and mechanical properties of oil shale samples. The uniaxial compressive strength and elastic modulus of the oil shale samples were changed with maximum variation rates of 64% and 65%, respectively. Meanwhile, the freeze-thaw coefficient of measured oil shale samples exponentially decreased with the increased number of freeze-thaw cycles, whereas the longitudinal wave velocity of tested samples ranged from 1602 m/s to 2464 m/s as a result of the new micropores inside the oil shale sample. Research results have enormous significance to the efficient and safe in situ exploitation of oil shale deposits.

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