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Failure characterization of fully grouted rock bolts under triaxial testing

Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 778-789页

作者： Hadi Nourizadeh Ali Mirzaghorbanali Mehdi Serati Elamin Mutaz Kevin McDougall Naj Aziz Centre for Future Materials(CFM) School of EngineeringUniversity of Southern QueenslandToowoombaQLD4350Australia School of Engineering University of Southern QueenslandSpringfield CentralQLD4300Australia School of Civil Engineering University of QueenslandSt LuciaQLD4072Australia School of Surveying and Build Environment University of Southern QueenslandToowoombaQLD4350Australia School of Civil Mining&Environmental EngineeringUniversity of WollongongWollongongNSW2500Australia

Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic stress conditions.Under these conditions,it is assumed that the intermediate principal stress(σ_(2))equals the minimum principal stress(σ_(3)).This assumption overlooks the potential variations in magnitudes of in situ stress conditions along all three directions near an underground opening where a rock bolt is installed.In this study,a series of push tests was meticulously conducted under triaxial conditions.These tests involved applying non-uniform confining stresses(σ_(2)≠σ_(3))to cubic specimens,aiming to unveil the previously overlooked influence of intermediate principal stresses on the strength properties of rock bolts.The results show that as the confining stresses increase from zero to higher levels,the pre-failure behavior changes from linear to nonlinear forms,resulting in an increase in initial stiffness from 2.08 kN/mm to 32.51 kN/mm.The load-displacement curves further illuminate distinct post-failure behavior at elevated levels of confining stresses,characterized by enhanced stiffness.Notably,the peak load capacity ranged from 27.9 kN to 46.5 kN as confining stresses advanced from σ_(2)=σ_(3)=0 to σ_(2)=20 MPa and σ_(3)=10 MPa.Additionally,the outcomes highlight an influence of confining stress on the lateral deformation of samples.Lower levels of confinement prompt overall dilation in lateral deformation,while higher confinements maintain a state of shrinkage.Furthermore,diverse failure modes have been identified,intricately tied to the arrangement of confining stresses.Lower confinements tend to induce a splitting mode of failure,whereas higher loads bring about a shift towards a pure interfacial shear-off and shear-crushed failure mechanism.

关键词： Rock bolts Bolt-grout interface bond strength Push test Triaxial tests

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bond strength of W-Cu/CuCr integrated material

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Transactions of Nonferrous Metals Society of China 2001年第6期11卷 835-837页

作者：范志康梁淑华薛旭西安理工大学陕西西安 710048

The bond strength of W Cu/CuCr integrated material was investigated. The results show that the fracture of W Cu/CuCr integrated material often takes place at W Cu/CuCr interface. Some alloying elements enhance the bond of W and CuCr alloy, which results in the increase of the strength of the W Cu/CuCr interface. And the fracture of the W Cu/CuCr integrated material occurs in the CuCr alloy part, not at the W Cu/CuCr interface. Chromium in CuCr alloy part of the integrated material can improve Cr diffusing from the CuCr alloy to W Cu composite and can be alloyed (near the W Cu/CuCr interface) in the W Cu composite. Thus the strength of W Cu/CuCr interface is also increased.

关键词： bond strength W Cu CuCr integrated material

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Effect of Self-adhesive Resin Cement and Tribochemical Treatment on bond strength to Zirconia

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International Journal of Oral Science 2010年第1期2卷 28-34页

作者： Akikazu Shinya Harunori Gomi Akiyoshi Shinya Department of Crown and Bridge School of Life Dentistry at TokyoThe Nippon Dental University

Aim To evaluate the interactive effects of different self- adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated： Maxcem （MA）, Smartcem （SM）, Rely X Unicem Aplicap （UN）, Breeze （BR）, Biscem （BI）, Set （SE）, and Clearfil SA luting （CL）. The specimens were grouped according to conditioning as follows： Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 μm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating ＋ silanization. Specimens were stored in distilled water at 37℃ for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, B1, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP- containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.

关键词： self-adhesive resin cement zirconia silica coating tribochemical treatment bond strength

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Effect of CeO_2 on Microstructure and bond strength of Fe-Ni-Cr Alloy

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Journal of Rare Earths 2005年第1期23卷 73-76页

作者：张振宇王智平梁补女 State Key Laboratory of New Nonferrous Metal Materials Lanzhou University of Technology Lanzhou 730050 China Department of Basic Courses Lanzhou Polytechnic College Lanzhou 730050 China

Fe-Ni-Cr alloy powders with and without 0.4% CeO_2 were flame sprayed on the surface of 1045 carbon steel substrate. The effect of rare earth oxide CeO_2 on the interface layer and microstructure was investigated by X-ray diffraction analysis, SEM and EDS. Based on our previous work, comparison on the microstructure of a Fe-Ni-Cr alloy with and without 0.4% CeO_2 addition was made. The correlation between the microstructure and bond strength was studied. The addition of CeO_2 in Fe-Ni-Cr alloy shows promise results for providing good bonding strength as well as tribological properties. The results show that the hardness of the coatings can be improved by addition of 0.4% CeO_2, and the shape of powders is more spheroidal. The combination of three aspects, namely small, well-distributed microstructure, the well-distributed matrix and promotion of diffusion leads to the improvement in bond strength of Fe-Ni-Cr alloy with addition of 0.4% CeO_2.

关键词： microstructure CeO_2 bond strength Fe-Ni-Cr alloy rare earths

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Wear Resistance and bond strength of Plasma Sprayed Fe/Mo Amorphous Coatings

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Journal of Iron and Steel Research(International) 2014年第10期21卷 969-974页

作者： Chao-ping JIANG Ya-zhe XING Feng-ying ZHANG Jian-min HAO Xu-ding SONG School of Materials Science and Engineering Chang'an University Key Laboratory of Road Construction Technology and Equipment MOE School of Construction MachineryChang'an University

Fe-based and Fe/Mo composite amorphous coatings were deposited on the surface of plain carbon steel substrates by atmospheric plasma spraying （APS）. With increasing the Mo alloy content, the microstructure of the coatings revealed more dense structure. The porosities of composite coating were all less than those of Fe-based coat- ing due to Mo alloy self-bonding performance. The ML10 friction and wear tester was employed to investigate the wear behaviors of the coatings under dry sliding conditions. It was found that the mass loss of the resultant coatings decreased with increasing Mo-based powders into the feedstock. This was attributed to the reduction of the delamina- tions resulting from improved intersplat bond with Mo addition.

关键词： atmospheric plasma spraying coating delamination wear bond strength

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Long-term Antibacterial Properties and bond strength of Experimental Nano Silver-containing Orthodontic Cements

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Journal of Wuhan University of Technology(Materials Science) 2013年第4期28卷 849-855页

作者：李福军李祖兵 LIU Gumei HE Hong Hospital of Stomatology Wuhan University

The purpose of this study was to evaluate the long time antibacterial properties and shear bond strength of experimental nano silver-containing cements （NSC）. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at five different weight ratios to obtain a series of nano silver-containing cements, then the antibacterial properties of three orthodontic cement products and five NSC samples were evaluated by the direct contact test （DCT） and the agar diffusion test （ADT）. The DCT, which was based on turbidness determination of bacterial growth in 96-well microtiter plates, was performed in both fresh and aged for 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, and 8 weeks tested materials. The shear bond strengthes of three orthodontic cement products and five NSC samples were examined using a universal testing machine. The ADT results indicated that there were no significant differences between NSCs and ORTHO LC fresh specimens. In the DCT experiment, all fresh silver nanoparticles-containing tested samples presented powerful antibacterial properties, but they gradually lost the effective antimicrobial agents with the extension of aging time. Finally, none of the tested materials maintained its antibacterial property after aging for 8 weeks. A gradually decreasing trend of bond strength presented with the increasing incorporation of nano silver base inorganic antibacterial powder into the glass ionomer cement, even though all the tested material specimens reached the ideal bond strength range. We may conclude that NSCs can contribute to decrease the demineralization rate around brackets without compromising bond strength.

关键词： long-term antibacterial properties bond strength nano silver-containing cements

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Effect of Freeze-thaw Cycles on bond strength between Steel Bars and Concrete

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Journal of Wuhan University of Technology(Materials Science) 2008年第4期23卷 584-588页

作者： JI Xiaodong SONG Yupu LIU Yuan State Key Lab of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China School of Soil and Water Conservation Beijing Forestery University Beijing 100083 China High School Affiliated to Renmin University of China Beijing 100080 China

The effect of freezing and thawing cycles on mechanical properties of concrete （compressive, splitting tensile strength） was experimentally investigated. According to the pullout test data of three kinds of deformed steel bars, the bond stress-slip curves after freezing and thawing were obtained. The empirical equations of peak bond strength were proposed that the damage accounted for effects of freezing and thawing cycle. Meanwhile, the mechanism of bond deterioration between steel bars and concrete after freezing and thawing cycles was discussed. All these conclusions will be useful to the durability design and reliability calculation of RC structures in cold region.

关键词： concrete steel bars bond strength freeze-thaw cycles

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Study of bond strength between various grade of Ordinary Portland Cement(OPC)and Portland Pozzolane Cement(PPC)mixes and different diameter of TMT bars by using pullout test

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Frontiers of Structural and Civil Engineering 2013年第1期7卷 39-45页

作者： A D POFALE S P WANJARI Department of Civil Engineering Visvesvarya National Institute of TechnologyNagpur 440010India

Since last two decades,the Portland Pozzolane Cement(PPC)is extensively used in structural concrete.But,till to date,a few literature is available on bond strength of concrete using PPC mixes.There are many literatures available on bond strength of concrete mixes using Ordinary Portland Cement(OPC).Hence,a comparative study was conducted on bond strength between OPC and PPC mixes.In the present investigation,total 24 samples consisting of M20,M35 and M50 grades of concrete and 16 and 25 mm diameter of TMT bar were tested for 7 and 28 days.The pullout bond test was conducted on each specimen as per IS:2770-1967/1997[1]and the results were observed at 0.25 mm slip at loaded end called as critical bond stress and at maximum bond load called as maximum bond stress.It was observed that the critical bond strength of PPC mixes is 10%higher than OPC mixes.Whereas,marginal improvement was noticed in maximum bond strength of PPC mixes.Hence,based on these findings,it could be concluded that development length for PPC mixes could be reduced by 10%as compared with same grade of OPC mixes.

关键词： bond strength Portland Pozzolane Cement(PPC)concrete Ordinary Portland Cement(OPC)concrete bond between concrete and steel pullout test development length

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bond strength of the Sn-Ti-Ⅹ Ternary Active Solders on Sialon Ceramic

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Journal of Materials Science & Technology 1993年第5期9卷 343-349页

作者： Aiping XIAN Zhongyao SI Institute of Metal Research,Academia Sinica,Shenyang,110015,China

The bond strength of the Sn based ternary active solders,Sn-5Ti with various contents of Ag,Cu,In, Ni or AI on sialon ceramic was investigated by the ceramic/ceramic joint joining.The bond strength of Sn-STi (about 80 MPa) may increase to 90-100 MPa by small addition of Ag or Cu (about 5-10%).A little Ni (about 1-3%) in the solder is slightly beneficial,but too more Ni (more than 5%) is harmful.Small addition of In is trivial,but too more In is detrimental.On the other hand,small addi- tion of AI in the active solder decreases greatly the bond strength of the solder,therefore it is very harmful.In discussion,three suggestions for selection of the third element to increase the bond strength of the soft solders on ceramic,i.***.with a high surface energy,benefiting to wetting on ce- ramic and strengthening the soft solder itself,have been made.

关键词： bond strength Sn-Ti-X ternary solders ceramic/ceramic joint

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Effect of Accessory Retention Forms on the bond strength of Resin-bonded Fixed Partial Dentures:a 3D Finite Element Study

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Chinese Journal of Biomedical Engineering(English Edition) 2016年第2期25卷 81-86,92页

作者： HAN Jin-yong WANG Chao FAN Yu-bo Key Lab for Boimechanics and Mechanobiology of Education Ministry School of Biological and Medical EngineeringBeihang University

Interface debonding between prostheses and abutments was the most frequent failure mode of resin-bonded fixed partials dentures(RBFPDs) in clinic. The purpose of this study was to investigate the effect of accessory retention forms on the bond strength of RBFPDs. Three types of 3D finite element models were constructed.The model of posterior metal plate RBFPD with spoon-shaped occlusal rest seats served as the control. The remaining two types of models based on the control added the retention form design of the pin hole and axial groove respectively. The axial or buccolingual load of 150 N was applied on the prosthesis, first premolar and first molar respectively. The maximum principal stresses of the adhesive layer in different models were calculated. Under the load of the same magnitude, the stress due to the buccolingual load was significantly higher than that due to the axial load in the adhesive layer. The proximal shoulder, occlusal rest seats wall and the proximal margin adjacent to the shoulder were the high risk region where the adhesive layer damaged easily. Compared with the control model, the pin and groove models could slightly decrease the stress in the adhesive layer after the axial loading, while the stress in the adhesive layer drastically decreased after horizontal loading and reduced by 22% and 31% respectively. These results indicate that the horizontal occlusal force has a more serious harm to the debonding of RBFPDs. In addition, the accessory retention forms(e.g. pin and axial groove retention forms) can decrease the stress level in the adhesive layer, which are conducive to increase the load-bearing capacity of RBFPDs.

关键词： resin-bonded fixed partial dentures finite element analysis bond strength accessory retention forms

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