scholarly journals Mechanical Characteristics and Stress Evolution of Cemented Paste Backfill: Effect of Curing Time, Solid Content, and Binder Content

2022 ◽  
Vol 8 ◽  
Author(s):  
Chen Hou ◽  
Liujun Yang ◽  
Lei Li ◽  
Baoxu Yan
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Peak Stress ◽  
Solid Content ◽  
Binder Content ◽  
Cemented Paste Backfill ◽  
Curing Time ◽  
Stress Evolution ◽  
Stress Strain ◽  
Paste Backfill

The clarification of the variation on the strength of the cemented paste backfill (CPB) under the coupling of multi-factor is the foundation of the CPB design of the mine. In this article, the physical and mechanical properties of the CPB under the coupling effect of curing time, solid content, and binder content were experimentally and theoretically investigated. The results show that 1) the increase in binder content can effectively increase the later strength of CPB. 2) A sensitivity parameter considering the span of multi-factor was constructed, indicating that the curing time has the greatest impact on the uniaxial compressive strength (UCS), and the variation in solid content has the least impact on it, which can be verified by the stress–strain curves. 3) Curing time and binder content can effectively change the stress evolution, which is reflected in reducing the strain corresponding to the peak stress, enhancing the characteristics of the peak stress and increasing stress drop. The results of this study aim to explain the essence of the influence of each factor on the mechanical behavior of CPB in the view of stress–strain evolution, which will help to better understand the mechanical characteristics of CPB and quantify the sensitivity of the mechanical properties to various factors.

scholarly journals Investigation on Mechanical Characteristics and Microstructure of Cemented Whole Tailings Backfill

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 592
Author(s):  
Armelle Estelle Belibi Tana ◽  
Shenghua Yin ◽  
Leiming Wang
Keyword(s):  
Yield Stress ◽  
Mechanical Characteristics ◽  
Xrd Analysis ◽  
Solid Content ◽  
Chemical Components ◽  
Cemented Paste Backfill ◽  
Before And After ◽  
Paste Backfill ◽  
Solids Content ◽  
Rheological Test

A paste backfill performance can be primarily evaluated through the mechanical and physical characteristics of the components involved. In this study, the effects of solid components’ tailings, binders and waters contents on microstructural evolution and mechanical properties of uncemented whole tailings backfill (CWTB) mixtures were investigated. Different mixtures of ordinary Portland cement of 1, 3 and 5 wt. % and solid concentrations at 72 wt. %, 74 wt. % and 75 wt. % were selected and rheological test was conducted to define the slump fluidity and yield stress. The microstructure of the solid component before and after the preparation and chemical composition were analyzed by the Scanning electron microscope and XRD analysis, respectively. The results show that a positive correlation between yield stress and slump values of CWTB paste slurries, the decrease of flow consistence leads to the reduction of the water content on the CWTB mixtures and the flow resistance of the paste. With the highest solids content, unconfined compressive strength (UCS) of CWTB varies between 0.1–0.9 MPa. Increasing the solid content affects the porosity and improves the strength resistance of CWTB mixtures. The findings in this study can therefore lead us to a statement that CWTB chemical components seem to be an important factor in cemented paste backfill (CPB) design and mine operations.

scholarly journals Shear Properties of Cemented Paste Backfill under Low Confining Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Andrew N. Pan ◽  
Murray W. F. Grabinsky ◽  
Lijie Guo
Keyword(s):  
Shear Strength ◽  
Mining Industry ◽  
Binder Content ◽  
Environmental Benefits ◽  
Direct Shear ◽  
Cemented Paste Backfill ◽  
Curing Time ◽  
Confining Stress ◽  
Strain Property ◽  
Paste Backfill

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.

Shear Strength of a Cemented Paste Backfill Submitted to High Confining Pressure

2016 ◽  
Vol 858 ◽  
pp. 219-224 ◽  
Author(s):  
Eduardo Eiler Batista de Araújo ◽  
Dragana Simon ◽  
Fagner Alexandre Nunes de França ◽  
Osvaldo de Freitas Neto ◽  
Olavo Francisco dos Santos Jr.
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Binder Content ◽  
Cemented Paste Backfill ◽  
Compression Tests ◽  
Mining Operations ◽  
Geomechanical Properties ◽  
Confining Pressures ◽  
Paste Backfill ◽  
Curing Method

Deep mining operations require special measures in order to keep safe and economic aspects. After mine ore is extracted, voids are created and need to be filled with high-strength, low-cost materials. Cemented Paste Backfill (CPB) has recently become one of the main alternatives in filling stopes. Although numerous papers have mentioned the magnitudes of the strength of this material, its behavior under high confining pressures is still not well understood. Therefore, the purpose of this study is to increase the knowledge regarding the CPB behavior. Triaxial compression tests were performed using a Hoek Cell and Load Frame System under high confining pressures. Samples with two different binder contents were used in order to obtain the CPB strength improvement. Besides the self-weight consolidation curing method, samples were subjected to a different curing method that simulated a zero gravity condition (rotating wheel) in the first curing day to compare their mixture properties. The results suggested that both curing method and binder content have influenced the geomechanical properties of Cemented Paste Backfill. By increasing the curing time, the CPB shear strength has increased slightly, whereas specimens with higher binder content presented a significant increase in shear strength values.

Effects of curing time and ice-to-water ratio on performance of cemented paste backfill containing ice slag

2019 ◽  
Vol 228 ◽  
pp. 116639 ◽  
Author(s):  
Lang Liu ◽  
Chao Zhu ◽  
Chongchong Qi ◽  
Mei Wang ◽  
Chao Huan ◽  
...  
Keyword(s):  
Cemented Paste Backfill ◽  
Curing Time ◽  
Paste Backfill ◽  
Water Ratio

scholarly journals Experimental Investigation on Mechanical Properties of In Situ Cemented Paste Backfill Containing Coal Gangue and Fly Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinguo Zhang ◽  
Shichuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Friction Angle ◽  
Coal Gangue ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Cemented paste backfill containing coal gangue and fly ash (CGFACPB) is an emerging backfill technique for coal mines that allows environmentally hazardous coal gangue and fly ash to be reused in the underground goaf. Meanwhile, CGFACPB can provide an efficient ground support and reduce the surface subsidence. Due to the difference of consolidation environment between the laboratory and the field, the mechanical properties of the cemented paste backfill vary significantly. In this paper, the core specimens were collected from an underground coal mine where the CGFACPB was used for coal mining, and the mechanical properties of the collected specimens were investigated. The cores were obtained from the underground coal mine, and then the standard cylinders or discs were prepared in laboratory. The uniaxial compressive strength (UCS), Young’s modulus, and Poisson’s ratio were determined by the compression tests, and the tensile strength was achieved by the Brazilian test. Then the internal friction angle and cohesion were calculated using the improved Mohr–Coulomb strength criterion. The results showed the development of UCS can be divided into four stages, and the final long-term stable value was about 5.1 MPa. The development of Young’s modulus had similar trend. Young’s modulus had a range from 550 MPa to 750 MPa and the mean value of 675 MPa. Poisson’s ratio gradually increased with the underground curing duration and eventually approached the stable value of 0.18. The failure type of compression samples was mainly single-sided shear failure. The development of tensile strength can be divided into two stages, and the stable value of the tensile strength was about 1.05 MPa. The development of cohesion can be divided into four stages, and the stable value was about 1.75 MPa. The stable value of the internal friction angle was about 25°. This study can provide significant references for not only the long-term stability evaluation of CGFACPB in the field but also the design of optimal recipe of the cemented paste backfill (CPB).

Relevance of SEM to Long-Term Mechanical Properties of Cemented Paste Backfill

2018 ◽  
Vol 36 (4) ◽  
pp. 2171-2187 ◽  
Author(s):  
Naguleswaran Niroshan ◽  
Ling Yin ◽  
Nagaratnam Sivakugan ◽  
Ryan Llewellyn Veenstra
Keyword(s):  
Mechanical Properties ◽  
Cemented Paste Backfill ◽  
Paste Backfill

scholarly journals Experimental Investigation on Mechanical Properties of Cemented Paste Backfill under Different Gradations of Aggregate Particles and Types and Contents of Cementing Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jiangyu Wu ◽  
Meimei Feng ◽  
Guansheng Han ◽  
Xiaoyan Ni ◽  
Zhanqing Chen
Keyword(s):  
Mechanical Properties ◽  
Cemented Paste Backfill ◽  
Compression Tests ◽  
Deformation Properties ◽  
Paste Backfill ◽  
Strength And Deformation ◽  
Cementing Material ◽  
Optimal Strength ◽  
Ae Signals ◽  
Aggregate Particles

Obtaining the optimal gradation of aggregate particles is beneficial for improving the strength of cemented paste backfill (CPB). Consequently, the uniaxial compression tests with acoustic emission (AE) monitoring were performed on CPB, for which the aggregate particles satisfied the Talbot grading theory. The effects of the Talbot indices of aggregate particles and types and contents of cementing materials on the mechanical properties of CPB were analyzed. The AE characteristics and stress-strain behaviors of CPB were discussed. The results show that the specific Talbot index reflected the optimal strength and deformation properties of CPB is 0.45, and the maximum UCS is 7.6 MPa. The mechanical properties of CPB also can be optimized by changing the type of cementing material and increasing the content of cementing material. The effects of the Talbot indices of aggregate particles and types and contents of cementing materials on the crack damages reflected by the AE signals of CPB are mainly observed in the oa stage and ab stage during the loading process.

Fluidity and Mechanical Behavior of Cement Solidified Lead-Zinc Mine Tailings

2014 ◽  
Vol 898 ◽  
pp. 383-386 ◽  
Author(s):  
Chun Lei Zhang ◽  
Shun Cai Wang ◽  
Fan Lu Min
Keyword(s):  
Mine Tailings ◽  
Cement Content ◽  
Strength Increase ◽  
Cemented Paste Backfill ◽  
Curing Time ◽  
Test Results ◽  
The World ◽  
Paste Backfill ◽  
Lead Zinc ◽  
Zinc Mine

Cemented paste backfill method has been widely used in many modern mines throughout the world due to the increasingly stringent environmental regulations and short of disposal land. This study presents experimental results on the use of Portland cement in the solidification of Pb-Zn tailings in China. Test results show UCS strength increase lineally with cement content, tailings concentration, and curing time, respectively. There exist a minimum cement content and tailings concentration to produce obvious strength. The fluidity decrease quickly with cement proportion and tailings concentration, under the satisfying of a minimum pumping fluidity, the increase of tailings concentration can effectively reduce the cement consumption so as to decrease the treatment cost.

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