scholarly journals Study on Mechanical Properties of the Basalt Fiber-Rubber Granular Concrete under Triaxial Stress Condition and Its Application

2020 ◽  
Vol 10 (23) ◽  
pp. 8540
Author(s):  
Duohua Wu ◽  
Zhiwen Li ◽  
Juli Li ◽  
Bo Peng ◽  
Hui Shen

To reduce the failure probability of rigid supporting structures caused by large deformation of deeply buried high-stress soft rock roadways, the mechanical properties and failure features of basalt fiber-rubber granular concrete (BFRGC) are investigated based on triaxial compression tests. The post-peak strain softening equations of BFRGC, based on the Mohr–Coulomb yield criterion, are deduced and then compiled in the finite-difference software (FLAC3D) to simulate the post-peak strain-softening process of BFRGC. Combined with practical engineering, the supporting effects of BFRGC with different proportions are evaluated by FLAC3D. The results of compression tests show that the yield strength of the BFRGC increases significantly when the mass percentage of basalt fiber is 0.4%. Moreover, mixing basalt fibers into both the plain concrete and rubber concrete can effectively restrain the development of the fractures under three-dimensional stress. The numerical results show that when the mass fractions of basalt fibers and rubber particles are 0.4% and 5–10%, respectively, both the plastic zone in the surrounding rocks and the deformation of the rigid supporting structures decrease obviously. It is indicated that the optimal ratio of BFRGC can effectively reduce the stress concentration around the roadway and improve the overall bearing capacity of the supporting structures.

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shan-Zhen Li ◽  
Liang Tang ◽  
Shuang Tian ◽  
Xian-Zhang Ling ◽  
Yang-Sheng Ye ◽  
...  

In the cold regions of China, coarse-grained materials are frequently encountered or used as backfilling materials in infrastructure construction, such as dams, highways, railways, and mineral engineering structures. Effects of confining pressure (0.2, 0.5, and 1 MPa) and frozen temperature (−2, −5, −10, and −15°C) on the stress-strain response and elastic modulus were investigated using triaxial compression tests. Moreover, the microscale structures of a coarse-grained material were obtained by X-ray computed tomography. The coarse-grained material specimens exhibited strain-softening and significant dilatancy behaviors during shearing. A modified model considering microstructures of the material was proposed to describe these phenomena. The predicted values coincided well with the experimental results obtained in this study and other literatures. The sensitivity analysis of parameters indicated that the model can simulate the initial hardening and post-peak strain-softening behavior of soils. And the transition of volume strain from contraction to dilatancy can also be described using this model. The results obtained in this study can provide a helpful reference for the analysis of frozen coarse-grained materials in geotechnical engineering.


Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1144
Author(s):  
Huan Dai ◽  
Yan Li ◽  
Mengdan Li

Remarkable hydrostatic pressures have a significant effect on the failure mechanical properties of seafloor minerals, which also affects the selection and development of mining excavation tools. In this paper, a Brazilian splitting test and triaxial compression test were adopted to investigate the strength and deformation behavior of two kinds of seafloor massive sulfides (SMS) samples at a small-scale size. Based on the mineralogical characterization of the studied samples, the mechanical properties were preliminarily correlated with their internal structures and mineral compositions. Results indicate that there is a significant difference in the triaxial compression deformation properties between the two kinds of SMS samples and the geotechnical data are controlled by mineral type and composition, including porosity. In general, the triaxial compression process of the two kinds of samples included initial compaction, elastic stage, yield stage, failure stage and residual stage, and shows strain softening characteristics after the peak. With the increase in confining pressure, the strain-softening behavior of the white sample is mitigated and gradually changes into strain-hardening. The peak strength and peak strain of the two samples increased linearly with the increase in confining pressure within the confining pressure range of these tests, and the failure pattern of the specimens also changed from a typical brittle failure to a ductile failure. The results of this study provide data to support further understanding of different kinds of SMS, and are of great significance in the design of efficient SMS exploitation equipment.


2021 ◽  
Vol 8 ◽  
Author(s):  
Shuai Guo ◽  
Peng Huang ◽  
A.J.S. (Sam) Spearing ◽  
Zhaojun Wang ◽  
Xiangjian Dong

The accumulated damage of the surrounding rocks induced by the existing coal mining activities (such as excavation and extraction) is the initial mechanical background of the rock and coal for the further mining operations. An energy-based Cumulative Initial Damage (CID) variable was proposed to account for such existing damage. With the MTS815 electro-hydraulic servo-controlled system, coal samples with different CID value were prepared by cyclic pre-loading and unloading process, and a novel experimental framework was presented to investigate the effect of CID on the further mechanical properties of the CID coal samples. The deformation characteristics, peak strength, peak strain, dilatancy characteristics, brittle-ductile transformation behavior, and microscopic structure of the CID coal samples were investigated in detail. The triaxial compression tests showed that with the increased of CID value, the compaction part of the coal samples was shorter and the strain softening stage became longer. When the CID value was increased from 0 to 0.521, the deviation stress and peak strain of the coal decreased by 31.4 and 37.7%, respectively and the main characteristic of the fracture morphology changed from cleavage steps to dimpling.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yugui Yang ◽  
Feng Gao ◽  
Hongmei Cheng ◽  
Yuanming Lai ◽  
Xiangxiang Zhang

The researches on the mechanical characteristic and constitutive models of frozen soil have important meanings in structural design of deep frozen soil wall. In the present study, the triaxial compression and creep tests have been carried out, and the mechanical characteristic of frozen silt is obtained. The experiment results show that the deformation characteristic of frozen silt is related to confining pressure under conventional triaxial compression condition. The frozen silt presents strain softening in shear process; with increase of confining pressure, the strain softening characteristic gradually decreases. The creep curves of frozen silt present the decaying and the stable creep stages under low stress level; however, under high stress level, once the strain increases to a critical value, the creep strain velocity gradually increases and the specimen quickly happens to destroy. To reproduce the deformation behavior, the disturbed state elastoplastic and new creep constitutive models of frozen silt are developed. The comparisons between experimental results and calculated results from constitutive models show that the proposed constitutive models could describe the conventional triaxial compression and creep deformation behaviors of frozen silt.


2016 ◽  
Vol 16 (2) ◽  
pp. 69-74 ◽  
Author(s):  
Ayman M. M. Abdelhaleem ◽  
Mohammed Y. Abdellah ◽  
Hesham I. Fathi ◽  
Montasser Dewidar

AbstractAcrylonitrile-butadiene-styrene (ABS) has great verity applications in aerospace and automobiles industries. Mechanical strength of the ABS is superior to even that of impact resistant polystyrene. In addition metallic coatings can be applied to the surface of ABS moldings. The main aim of the present work is to investigate the mechanical properties of additives of basalt fibers (BF) to ABS with (5, 10, and 15) wt% embedded into the polymer matrix by using plastic injection molding technique. This new perceptions has been done on basalt fibers that have a potential low cost with its good mechanical performance. The ultimate tensile strength that obtained from the composite with 15 wt% is 56.67 MPa with 40.52 % increase value than neat ABS, Young’s modulus gradually increases with increasing the amount of additives. Impact un-notched strength decreases with a reported increment of 24.617 KJ.m–2. A Rockwell hardness test is also used and with the increases of additives the amount of hardness of the composite increases. A scan electron microscopy (SEM) on the fracture surface is captured to check the morphologies structure of the composite comparable with a neat ABS. and it is showed a very good distribution and bonding of the B.F. with the pure ABS. As well as the cost of the ABS and BF is reduced by a percentage of 15 %.


2016 ◽  
Vol 858 ◽  
pp. 91-97
Author(s):  
Jun Hua Xiao ◽  
Wen Qi Zheng

To investigate the macroscopic mechanical properties of undisturbed structural Xiashu loess in the lower reaches of China’s Yangtze River under triaxial compression, and obtain the intrinsic explanations for the macroscopic mechanical properties from the microscopic point of view, in laboratory, triaxial compression tests were carried out, microstructure images of sheared samples were collected by scanning electron microscope (SEM), and quantitative parameters of microstructure (mainly about particle or pore size, distribution, and alignment) were extracted by digital image processing technique. Based on the test results, the deviator stress-strain relationships of both undisturbed and remoulded Xiashu loess, the structural strength, and the microstructural evolution mechanism about the formation of shear failure zone of Xiashu loess under triaxial compression were analyzed.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Jun-Ling Qin ◽  
Wei-Guo Qiao ◽  
Deng-Ge Lin ◽  
Shuai Zhang ◽  
Ji-Yao Wang

The strength of crumb rubber mortars can be improved by the addition of basalt fibers. However, limited studies have been conducted on basalt fiber crumb rubber mortars (BF-CRM), and the constitutive model is still very immature. In this paper, uniaxial compressive stress-strain curves are obtained for several groups of BF-CRM specimens with different contents. By comparison with the GZH model, modified GZH parameters that can be used in a BF-CRM constitutive model are obtained. Then, taking the support scheme of the main substation of a mine as the background, FLAC3D is used to simulate the roadway support, BF-CRM replaces the ordinary mortars in the original support, and triaxial compression tests are performed at different confining pressures. In this way, the application of BF-CRM in roadway support is studied and analyzed.


2019 ◽  
Vol 9 (10) ◽  
pp. 2031 ◽  
Author(s):  
Hanbing Liu ◽  
Shiqi Liu ◽  
Shurong Wang ◽  
Xin Gao ◽  
Yafeng Gong

Basalt fibers are widely used in the modification of concrete materials due to its excellent mechanical properties and corrosion resistance. In this study, the basalt fibers were used to modify reactive powder concrete (RPC). The effect of four mix proportion parameters on the working and mechanical properties of basalt fiber reactive powder concrete (BFRPC) was evaluated by the response surface methodology (RSM). The fluidity, flexural and compressive strength were tested and evaluated. A statistically experimental model indicated that D (the silica fume to cement ratio) was the key of interactions between factors, affecting other factors and controlling properties of BFRPC. The increase in basalt fiber content had a remarkable effect on increasing the flexural and compressive strength when D = 0.2. The addition of basalt fiber obviously improved the mechanical properties of RPC. While when D = 0.4, the decrease of fiber content and the increase of quartz sand content could increase the compressive strength.


2017 ◽  
Vol 52 (14) ◽  
pp. 1907-1914 ◽  
Author(s):  
Yang Zhiming ◽  
Liu Jinxu ◽  
Feng Xinya ◽  
Li Shukui ◽  
Xu Yuxin ◽  
...  

Basalt fiber reinforced aluminum matrix composites with different fiber contents (i.e. 0 wt%, 10 wt%, 30 wt% and 50 wt%) were prepared by hot-press sintering. Microstructure analysis indicates that basalt fibers are uniformly distributed in 10% basalt fiber reinforced aluminum matrix composite. The interfacial bonding between basalt fibers and aluminum matrix is good, and there is no interface reaction between basalt fiber and aluminum matrix. Quasi-static tensile, quasi-static compression and dynamic compression properties of basalt fiber reinforced aluminum composites were studied, and the influences of basalt fiber content on mechanical properties were discussed. Meanwhile, the failure mechanisms of basalt fiber reinforced aluminum matrix composites with different fiber content were analyzed.


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