Dynamic behavior of a running crack crossing mortar-rock interface under impacting load

Qiu, Hao; Zhu, Zheming; Wang, Fei; Wang, Meng; Zhou, Changlin; Luo, Caisong; Wang, Xingyu; Mao, Hongyun

doi:10.1016/j.engfracmech.2020.107202

Cited by 18 publications

(7 citation statements)

References 24 publications

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“…In addition to strength performance, the failure processes of brittleness materials are also important. Some researchers have studied the failure processes of brittleness materials [ 39 , 40 ]. Since the risk of fracture will increase under sudden loads, it is beneficial to take measures to increase elastic behavior.…”

Section: Introductionmentioning

confidence: 99%

Influence of Replacing Cement with Waste Glass on Mechanical Properties of Concrete

et al. 2022

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In this study, the effect of waste glass on the mechanical properties of concrete was examined by conducting a series of compressive strength, splitting tensile strength and flexural strength tests. According to this aim, waste glass powder (WGP) was first used as a partial replacement for cement and six different ratios of WGP were utilized in concrete production: 0%, 10%, 20%, 30%, 40%, and 50%. To examine the combined effect of different ratios of WGP on concrete performance, mixed samples (10%, 20%, 30%) were then prepared by replacing cement, and fine and coarse aggregates with both WGP and crashed glass particles. Workability and slump values of concrete produced with different amounts of waste glass were determined on the fresh state of concrete, and these properties were compared with those of plain concrete. For the hardened concrete, 150 mm × 150 mm × 150 mm cubic specimens and cylindrical specimens with a diameter of 100 mm and a height of 200 mm were tested to identify the compressive strength and splitting tensile strength of the concrete produced with waste glass. Next, a three-point bending test was carried out on samples with dimensions of 100 × 100 × 400 mm, and a span length of 300 mm to obtain the flexure behavior of different mixtures. According to the results obtained, a 20% substitution of WGP as cement can be considered the optimum dose. On the other hand, for concrete produced with combined WGP and crashed glass particles, mechanical properties increased up to a certain limit and then decreased owing to poor workability. Thus, 10% can be considered the optimum replacement level, as combined waste glass shows considerably higher strength and better workability properties. Furthermore, scanning electron microscope (SEM) analysis was performed to investigate the microstructure of the composition. Good adhesion was observed between the waste glass and cementitious concrete. Lastly, practical empirical equations have been developed to determine the compressive strength, splitting tensile strength, and flexure strength of concrete with different amounts of waste glass. Instead of conducting an experiment, these strength values of the concrete produced with glass powder can be easily estimated at the design stage with the help of proposed expressions.

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Section: Introductionmentioning

confidence: 99%

Influence of Replacing Cement with Waste Glass on Mechanical Properties of Concrete

et al. 2022

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“…Case exploration with various numerical simulation software [14,15], will provide a new idea for the research on the damage evolution of the jointed rock mass. After analysis of the deformation and failure of concentrated parallel jointed rock mass with different spacing and number [16], as well as the failure crack propagation process [17,18], disparities can be seen in the crack initiation location of different types of crack propagation. Besides, SHPB test results can be verified and further analyzed through numerical simulation (ANSYS) [19].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading

Pan

Wang

et al. 2021

Materials

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The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.

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“…In the SHPB test, the three-wave method [27,28] was used to analyze the dynamic characteristics of granite specimens.…”

Section: Calculation Of the Strain And Stressmentioning

confidence: 99%

A New Index of Energy Dissipation Considering Time Factor under the Impact Loads

Wang

Guo

et al. 2022

Materials

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Rock failure phenomena are accompanied by abundant energy variation, and the energy dissipation can explain the dynamic mechanical characteristics of the rock. In this study, a series of granite specimens (a total of 60) with different aspect ratios were dynamically loaded by a split Hopkinson pressure bar (SHPB) to explain the energy dissipation and the rock-crushing degree under dynamic load. A new index, namely energy time density (wtd), is proposed to evaluate the energy dissipation considering the time factor. The relationships between strain rate, energy time density, and specific energy absorption are analyzed. A metric (Ku) is defined to describe the degree of rock fragmentation quantitatively. The correlations of fractal dimension and Ku with different impact pressures are compared. It was concluded that there is a noticeable peak point in the energy time density curve. The energy time density of the stress equilibrium point is three times that of the peak point. The energy time density declines after the peak point, then the energy consumption density tends to be stable. The linear relationship between strain rate and peak point energy time density is stronger. The new index can describe energy dissipation well under dynamic loading. In addition, the experimental results indicate that the degree of crush Ku can describe the degree of crush, and the effect of fractal dimension to quantify the fracture characteristics of the rocks is less good in this test. The crushing degree of rocks increases with the increase of strain rate. Furthermore, the prediction effect of energy time density is better than that of strain rate about Ku.

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Dynamic behavior of a running crack crossing mortar-rock interface under impacting load

Cited by 18 publications

References 24 publications

Influence of Replacing Cement with Waste Glass on Mechanical Properties of Concrete

Influence of Replacing Cement with Waste Glass on Mechanical Properties of Concrete

Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading

A New Index of Energy Dissipation Considering Time Factor under the Impact Loads

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