Microscopic damage and dynamic mechanical properties of rock under freeze–thaw environment

Zhou, Keping; Li, Bin; Li, Jielin; Deng, Hongwei; Bin, Feng

doi:10.1016/s1003-6326(15)63723-2

Cited by 148 publications

(64 citation statements)

References 10 publications

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“…31) As a result, the fluids in different cracks and pores show different relaxation times. The NMR relaxation method 31),32) is suitable for characterising the pore structures of concrete and rock.…”

Section: Nuclear Magnetic Resonance Analysismentioning

confidence: 99%

Assessment of the freeze–thaw resistance of concrete incorporating carbonated coarse recycled concrete aggregates

Wang

et al. 2017

J. Ceram. Soc. Japan

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This study aims to characterise the freezethaw resistance of concrete incorporating carbonated coarse recycled concrete aggregate (C-CRCA) at partial or full replacement rates of coarse natural aggregate (CNA). Experimental work is conducted for C-CRCA with varying CO 2 curing time (0 day, 3 day, 7 day) and C-CRCA weight replacement percentages (0, 20, 50, 100%) for concrete production. Weight loss, relative dynamic modulus of elasticity (RDME) and residual compressive strength were monitored after 300 freezethaw cycles. Pore size distribution and crack volume variation were also measured via nuclear magnetic resonance to investigate changes in the microstructure of the concrete interior. The compressive strength of concrete decreases with the replacement percentage of CNA by the C-CRCA. The internal freezethaw resistance of concrete with C-CRCA was higher or equal to those of concrete with CRCA and CNA. The total replacement of CNA by C-CRCA led to the highest RDME, and 50% replacement of CNA by C-CRCA led to the highest residual compressive strengths after the freezethaw cycles. However, the weight loss was more severe with the increasing replacement of CNA by C-CRCA. Increasing CO 2 curing time improved the frost resistance of C-CRCA concrete. The analyses of concrete mesostructure based on pore size distribution and crack volume variation agreed with the results of RDME and the compressive strength of concrete.

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Section: Nuclear Magnetic Resonance Analysismentioning

confidence: 99%

Assessment of the freeze–thaw resistance of concrete incorporating carbonated coarse recycled concrete aggregates

Wang

et al. 2017

J. Ceram. Soc. Japan

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“…The mechanical properties and fracture behaviors of rock are closely associated with the micro-damage characteristics of rock. The number of freeze-thaw cycles will cause different damage degrees to the microstructure of rock [18][19][20]. In this paper, the microstructure characteristics of saturated yellow sandstone under different numbers of freeze-thaw cycles are studied by scanning electron microscope (SEM).…”

Section: Analysis Of Meso-damage Characteristics Of Freeze-thaw Yellomentioning

confidence: 99%

Experimental Study on Physical-mechanical Properties and Fracture Behaviors of Saturated Yellow Sandstone Considering Coupling Effect of Freeze-Thaw and Specimen Inclination

Chen

et al. 2020

Sustainability

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The effect of freeze-thaw on the physical-mechanical properties and fracture behavior of rock under combined compression and shear loading was crucial for revealing the instability mechanism and optimizing the structure design of rock engineering in cold regions. However, there were few reports on the failure behavior of rock treated by freeze-thaw under combined compression and shear loading due to the lack of test equipment. In this work, a novel combined compression and shear test (C-CAST) system was introduced to carry out a series of uniaxial compression tests on saturated yellow sandstone under various inclination angles (θ = 0°, 5°, 10°, and 15°) and the number of freeze-thaw cycles (N = 0, 20, 40, and 60). The test results showed that the P-wave velocity dramatically decreased, while the rock quality and porosity increased gradually as N increased; the peak compression strength and elastic modulus obviously decreased with the increasing θ and N, while the peak shear stress increased gradually with the increasing θ and decreased with the increase of N, indicating that the shear stress component can accelerate the crack propagation and reduce its resistance to deformation. The acoustic emission (AE) results revealed that the change of crack initiation (CI) stress and crack damage (CD) stress with the θ and N had a similar trend as that of the peak compression strength and elastic modulus. Particularly, the CI and CD thresholds at 60 cycles were only 81.31% and 84.47% of that at 0° cycle and indicated a serious freeze-thaw damage phenomenon, which was consistent with the results of scanning electron microscopy (SEM) with the appearance of some large-size damage cracks. The fracture mode of sandstone was dependent on the inclination angle. The failure mode developed from both the tensile mode (0°) and combined tensile-shear mode (5°) to a pure shear failure (10°–15°) with the increasing inclination angle. Meanwhile, the freeze-thaw cycle only had an obvious effect on the failure mode of the specimen at a 5° inclination. Finally, a novel multivariate regression analysis method was used to predict the peak compression strength and elastic modulus based on the initial strength parameters (θ = 0°, N = 0). The study results can provide an important reference for the engineering design of rock subjected to a complex stress environment in cold regions.

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“…Through the above previous analysis of the research results on the mechanical properties of rock under F-T cycles, scholars mainly centered on the physical and statics mechanical properties; only a few works have been published about the dynamic mechanical behaviors of freeze-thaw weathered rock. The microscopic damage characteristics and dynamic mechanical parameters of sandstone subjected to repeated freeze-thaw cycles were investigated from the NMR tests and impact loading tests [17]. Static and dynamic mechanical properties of sedimentary rock after freeze-thaw weathering were obtained from the SEM technique, static compression, and SHPB impact tests [3].…”

Section: Shock and Vibrationmentioning

confidence: 99%

“…Thus, changes in the internal microstructure are the crucial factor causing the damage of rock after freeze-thaw processes [14]. Also, some advanced technologies such as X-ray computed tomography (X-ray CT), scanning electron microscope (SEM), and nuclear magnetic resonance (NMR) are used to analyze the evolution of the microstructure at the different number of freeze-thaw cycles [12,[15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

NMR Pore Structure and Dynamic Characteristics of Sandstone Caused by Ambient Freeze-Thaw Action

Zhou

Deng

et al. 2017

Shock and Vibration

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For a deeper understanding of the freeze-thaw weathering effects on the microstructure evolution and deterioration of dynamic mechanical properties of rock, the present paper conducted the nuclear magnetic resonance (NMR) tests and impact loading experiments on sandstone under different freeze-thaw cycles. The results of NMR test show that, with the increase of freezethaw cycles, the pores expand and pores size tends to be uniform. The experimental results show that the stress-strain curves all go through four stages, namely, densification, elasticity, yielding, and failure. The densification curve is shorter, and the slope of elasticity curve decreases as the freeze-thaw cycles increase. With increasing freeze-thaw cycles, the dynamic peak stress decreases and energy absorption of sandstone increases. The dynamic failure form is an axial splitting failure, and the fragments increase and the size diminishes with increasing freeze-thaw cycles. The higher the porosity is, the more severe the degradation of dynamic characteristics is. An increase model for the relationships between the porosity or energy absorption and freeze-thaw cycles number was built to reveal the increasing trend with the freeze-thaw cycles increase; meanwhile, a decay model was built to predict the dynamic compressive strength degradation of rock after repeated freeze-thaw cycles.

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Microscopic damage and dynamic mechanical properties of rock under freeze–thaw environment

Cited by 148 publications

References 10 publications

Assessment of the freeze–thaw resistance of concrete incorporating carbonated coarse recycled concrete aggregates

Assessment of the freeze–thaw resistance of concrete incorporating carbonated coarse recycled concrete aggregates

Experimental Study on Physical-mechanical Properties and Fracture Behaviors of Saturated Yellow Sandstone Considering Coupling Effect of Freeze-Thaw and Specimen Inclination

NMR Pore Structure and Dynamic Characteristics of Sandstone Caused by Ambient Freeze-Thaw Action

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