Hydration Effects on Specific Gravity and Void Ratio of Cemented Paste Backfill

Jafari, Mousa; Shahsavari, Mohammad; Grabinsky, Murray

doi:10.1520/gtj20190094

Cited by 16 publications

(8 citation statements)

References 36 publications

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“…e previous studies showed that the mechanical properties of CPB depend on its physical and chemical characteristics of the binder type, particle size, water content, and tailings' mineralogy [3,10,14,16,19,20]. ese mechanical properties vary significantly with the binder content and curing time.…”

Section: Methodsmentioning

confidence: 99%

“…e deposits were extracted with a mixture of long hole stope and Alimak stope and subsequently backfilled with CPB. e ore is milled to paste consistency with more than 45% passing 0.020 mm as shown in Figure 2 [19]. e tailing stream consists of silica, quartz, feldspar, and plagioclase.…”

Section: Introductionmentioning

confidence: 99%

“…e tailing stream consists of silica, quartz, feldspar, and plagioclase. Table 1 shows the chemical composition of the tailing , Table 2 shows the chemical compositions of the binder, and Figure 2 shows the grain size distribution of tailings [19]. Sulfides in the tailings can be oxidized which alters the material's initial grey to orange color when exposed to oxygen [9].…”

Section: Introductionmentioning

confidence: 99%

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Shear Properties of Cemented Paste Backfill under Low Confining Stress

Pan

Grabinsky

Guo

2021

Advances in Civil Engineering

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Cemented paste backfill (CPB) plays an important role in the mining industry due to safety, cost efficiency, and environmental benefits. Studies on CPB have improved the design and application of paste backfill in underground mines. Direct shear is one of the most fundamental parameters for assessing backfill strength. This study harnesses direct shear tests to explore the low confining stress behavior of CPB. We perform all the tests in a standard apparatus on the combination of three binder contents of 4.2%, 6.9%, and 9.7% CPB with four curing times of 3, 7, 14, and 28 days, respectively. The applied confining stress levels vary in a range according to the in situ regime. Results are presented by strength envelope, stress-strain property, and shear strength with curing time and binder content. The data suggest that the shear strength follows the Mohr–Coulomb envelope in which the shear strength and behavior are time and binder content dependent. In addition, the results show that shear strength is strongly related to the binder content than the curing time, namely, the higher the degree of binder hydration, the higher the cementation binding force between CPBs.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Shear Properties of Cemented Paste Backfill under Low Confining Stress

Pan

Grabinsky

Guo

2021

Advances in Civil Engineering

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“…The water collected from the mentioned mine's paste plant and ordinary Portland cement were other constituents of this CPB. More information about the chemical compositions of tailings and cement, and concentrations of ions in the process water may be found in Jafari et al (2020c).…”

Section: Materials Descriptionmentioning

confidence: 99%

Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)

Jafari

Grabinsky

2021

Preprint

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Deep and high-stress mining results in stress transfers onto the previously placed backfill, and mines have recorded several MPa induced backfill stress. Understanding the backfill-rock mass interaction is therefore critical. Previous work considered tabular ore bodies undergoing primarily one-dimensional compression and showed how the backfill reaction curves could be estimated from oedometer laboratory test results. This work considers massive orebodies and develops a similar approach based on isotropic compression curves. Isotropic compression tests exceeding 6 MPa are carried out on samples with 3.0–11.1% binder content, tested at 1-day cure time to 28-day cure time. The compression curve is characterized in three stages: initial elastic compression up to a yield point, followed by a transition stage to the start of a final stage with a linear post-yield compression line in \({\epsilon }_{v}-\text{l}\text{o}\text{g}\left({p}^{\text{'}}\right)\) space. Because these isotropic compression tests are rare (the reported results are the first for Cemented Paste Backfill), attempts are made to relate the isotropic compression test parameters to parameters from the more commonly used Unconfined Compression Strength (UCS) tests. Unifying equations as functions of binder content and cure time are found to determine the initial yield stress and the peak strength from UCS tests. These are then related to the corresponding parameters in isotropic compression. Finally, the slope of the post-yield compression line is found as a function of UCS, thereby enabling complete reconstruction of the isotropic compression response based on parameters from carefully controlled UCS tests, as functions of binder content and cure time. Although the calibrated parameters are specific to the studied mine’s materials, the framework is general and applicable to other mines’ CPBs.

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“…Based on the above literature review, a research program was initiated to study the hybrid failure properties of CPB. In this study, CPB designs were based on the operational requirements and regional ground conditions which reflected the current operation at the mines [2,[17][18][19][20]. Our objective is to determine the coupled stress and elastic parameters of CPB.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Failure of Cemented Paste Backfill

et al. 2021

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The hybrid failure is a coupled failure mechanism under the action of tensile and shear stresses. The failure is critical in cemented paste backfill (CPB) since there are no visible signs prior to the failure. Few studies have been conducted on the coupled stress response of CPB. This is most likely due to a lack of suitable laboratory equipment and test procedures. This paper presents a new punching shear apparatus to evaluate the hybrid failure of CPB. We harness two-dimensional finite element analysis (FEA) for supplementing experimental study in providing stress transformation, deformation, and possible failure mechanisms. Our study suggests that the coupled stress is a combination of tensile and shear strength in function of the angle of the frustum. The strengths measured by the coupled stress are comparable to those measured by direct shear and tensile strength tests, in which the strength properties of CPB are curing time and binder content dependent. The FEA results substantiate the effectiveness of proposed model for predicting the hybrid failure of CPB.

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Hydration Effects on Specific Gravity and Void Ratio of Cemented Paste Backfill

Cited by 16 publications

References 36 publications

Shear Properties of Cemented Paste Backfill under Low Confining Stress

Shear Properties of Cemented Paste Backfill under Low Confining Stress

Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)

Hybrid Failure of Cemented Paste Backfill

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