Expansion and strength properties of cemented backfill using sulphidic mill tailings

Yin, Shenghua; Shao, Yajian; Wu, Aixiang; Wang, Yiming; Chen, Xun

doi:10.1016/j.conbuildmat.2018.01.005

Cited by 61 publications

(10 citation statements)

References 44 publications

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“…The CPB slurry was stirred evenly in cylindrical bottom-drained column moulds (∅50 mm × 100 mm). After a rest period, CPB specimens were placed into a curing box at a temperature of 20 ± 1°C and a relative humidity of 95 ± 1% (Yin et al, 2018). Then the specimens, cured for 3, 7, 14, and 28 days, were evaluated by SEM test, NMR test, and UCS test, respectively.…”

Section: Preparation Of Cpb Specimensmentioning

confidence: 99%

Pore Structure Characteristics and Its Effect on Mechanical Performance of Cemented Paste Backfill

et al. 2021

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The development of cemented paste backfilling (CPB) technology has made an important contribution to the mining economy. As a kind of porous material, the pore structure characteristic of cemented paste backfill (CPB) is strongly correlated to its mechanical properties. In this study, CPB specimens were prepared with tailings/cement ratios (T/C ratio) of 4, 6, 10 and curing durations of 3, 7, 14, and 28 days, respectively. Pore structures characteristics of CPB specimens were investigated using nuclear magnetic resonance (NMR) and scanning electronic microscopy (SEM). The uniaxial compressive strength (UCS) was adopted to illustrate the mechanical property of CPB specimens. The coupling effects of T/C ratio and curing time on the pore characteristics of CPB as well as the effect of pore size on the UCS were analyzed. The results indicated that: 1) the microstructural integrity of CPB was highly related to the development status of the pore structure, which can be represented by micro-parameters like porosity, average pore area, etc. 2) a similar normal distribution curve was observed from the four kinds of pore structure in CPB. As the curing time increased, the peak of the pore size curve shifted left, and the peak value decreased, which means that the pore size in CPB decreased and became much concentrated; 3) the extension of the most probable pore size led to the cross-connection of pores and resulted in the fracture of CPB, which was shown as a crack on the main section.

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Section: Preparation Of Cpb Specimensmentioning

confidence: 99%

Pore Structure Characteristics and Its Effect on Mechanical Performance of Cemented Paste Backfill

et al. 2021

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“…Moreover, the greater the concentration of sulphate is in the environment, the more pronounced its effect on early strength. Yin and Yan et al [10,11]. studied the effect of sulphate erosion on CPB and found that the sulphate concentration influenced the evolution of strain and the free expansion ratio of CPB.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Microstructure and Erosion Mechanisms of Solid Waste Cemented Paste Backfill under the Combined Action of Dry–Wet Cycles and Sulphate Erosion

et al. 2022

Materials

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Solid waste cemented paste backfill (SWCPB) meets the needs of coal mining area management. SWCPB is a cementitious paste backfill material without added cement and is made only from oil shale residue (OSR), steel slag (SS), soda residue (SR) and water. In this study, mine water characteristics were simulated by combining dry–wet cycling experiments with sulphate erosion experiments. SWCPB was assessed regarding appearance, mass loss, and unconfined compressive strength (UCS), and the erosion products were microscopically analysed with X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The mechanism for erosion of the SWCPB by sulphate-rich mine water was comprehensively analysed and revealed. Research showed that the erosion mechanism was divided into two parts: chemical and physical erosion. Low concentrations of sodium sulphate promoted hydration, thereby contributing to the increased mass and strength of SWCPB. At high sodium sulphate concentrations, the erosion mainly consumed Ca(OH)2 within the material, and the main generated erosion products were gypsum and ettringite (AFt). This was accompanied by the destructive effects of Na2SO4 crystal expansion, which resulted in damage and the reduced workability of the SWCPB. The whole erosion process was continuous, mainly due to transformations of pits, pores and cracks. The conclusions of this study may provide appropriate guidance for application of SWCPB materials in the treatment of coal mine backfills. In addition, the corresponding theoretical analysis of the erosion mechanism for SWCPB materials is provided.

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“…A large number of experimental studies have been conducted on the physical and mechanical properties of CTB. The unconfined compressive strength (UCS) is considered as the most important parameter in the backfill design of underground mines [10][11][12][13]. However, in the actual mining process, the drying shrinkage and dynamic disturbance, such as the extraction of adjacent stopes often induce cracks in the CTB structure [14,15].…”

Section: Introductionmentioning

confidence: 99%

Effect of fiber on early strength and interface stiffness of cemented tailings backfill

Jin

Yuan

et al. 2022

Mater. Res. Express

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This paper studies the early mechanical properties of fiber-reinforced cemented tailings backfill (CTB) and discuss its modification mechanism. The effects of fiber types and addition (polypropylene fiber, basalt fiber and glass fiber) on unconfined compressive strength of CTB were studied by unconfined compressive strength test (UCS). Scanning electron microscopy (SEM) was used to investigate the microstructure of fiber-reinforced CTB. Based on the theory of interface mechanics and the contact mechanism of fiber interface, the evolution mechanism of fiber-reinforced CTB interface characteristic stiffness was further explored. The results show that the fiber type and content have a significant effect on the strength of CTB, and the optimum addition of fibers is 0.4%. The strength of fiber-reinforced CTB samples increased first and then decreased with the increase of fiber content. The stress of CTB sample without fibers reaches the maximum value when the strain is 1.01%, while introduction of basalt fiber increases that value to 3.74%. In addition, the microstructure characteristics show that the hydration products around the fiber make the CTB sample have better compactness, and fibers can effectively inhibit the crack development of the CTB samples. Finally, using the theory of interface mechanics, it is found that the interface stiffness of CTB sample with basalt fibers is the largest, but the interface contact stiffness increases first and then decreases with the increase of fiber content, which is consistent with the law of macroscopic strength change.

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Expansion and strength properties of cemented backfill using sulphidic mill tailings

Cited by 61 publications

References 44 publications

Pore Structure Characteristics and Its Effect on Mechanical Performance of Cemented Paste Backfill

Pore Structure Characteristics and Its Effect on Mechanical Performance of Cemented Paste Backfill

Experimental Study on Microstructure and Erosion Mechanisms of Solid Waste Cemented Paste Backfill under the Combined Action of Dry–Wet Cycles and Sulphate Erosion

Effect of fiber on early strength and interface stiffness of cemented tailings backfill

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