Effects of coupled sulphate and temperature on internal strain and strength evolution of cemented paste backfill at early age

Yan, Baoxu; Zhu, Wancheng; Hou, Chen; Yu, Yang; Guan, Kai

doi:10.1016/j.conbuildmat.2019.116937

Cited by 28 publications

(5 citation statements)

References 53 publications

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“…To analyse the micro hydration mechanism of CPB, Yan et al [ 14 ] performed a study on the trend of the coupling effect of sulfate and temperature on the early hydration reaction and mechanical properties of CPB. It was found that both sulfate and temperature significantly affected the hydration process and thus influenced the internal volume change and mechanical properties of CPB.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Cemented Oil Shale Residue–Steel Slag–Ground Granulated Blast Furnace Slag Backfill and Its Environmental Impact

Sun

et al. 2021

Materials

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A new environmentally friendly cemented oil shale residue–steel slag–ground granulated blast furnace slag backfill (COSGB) was prepared using oil shale residue (OSR), steel slag (SS) and ground granulated blast furnace slag (GGBS) as constituent materials. Based on univariate analysis and the Box–Behnken design (BBD) response surface method, the three responses of the 28 days unconfined compressive strength (UCS), slump and cost were used to optimize the mix ratio. Using a combination of scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP), the reaction products, microscopic morphology and pore structure of the specimens with the optimal mix ratio at different curing ages were analyzed. The influence of heavy metal ions from the raw materials and the COSGB mixtures on the groundwater environment was studied by leaching tests. The research demonstrates that the optimal mix ratio is GGBS mixing amount 4.85%, mass ratio of SS to OSR 0.82, and solid mass concentration 67.69%. At shorter curing age, the hydration products are mainly calcium alumino silicate hydrate (C-A-S-H) and calcium silicate hydrate (C-S-H) gels. With the increase of curing age, ettringite (AFt) and C-S-H gels become the main source of the UCS. Meanwhile, the porosity of the filler decreases continuously. The leaching concentration of heavy metal ions from the COSGB mixtures is all lower than the leaching concentration of raw materials and meet the requirements of the Chinese groundwater quality standard (GB/T 14848-2017). Therefore, this new COSGB cannot pollute the groundwater environment and meets backfill requirements. The proposed technology is a reliable and environmentally friendly alternative for recycling OSR and SS while simultaneously supporting cemented paste backfill (CPB).

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Section: Introductionmentioning

confidence: 99%

Preparation of Cemented Oil Shale Residue–Steel Slag–Ground Granulated Blast Furnace Slag Backfill and Its Environmental Impact

Sun

et al. 2021

Materials

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“…The FR-CPB specimens were prepared through a mixture of quartz tailings, Portland cement, tap water, and polypropylene microfibers. The quartz tailings are composed of 99.8% silicon dioxide and are inert materials which can reduce the uncertainties (e.g., the effect of sulphate anions on the cement hydration and microstructure of CPB) to a minimum level [8]. The particle size distribution of the quartz tailings was analyzed and the results were plotted in Fig.…”

Section: Methodsmentioning

confidence: 99%

Mechanical Properties and Behavior of Early-Age Fiber-Reinforced Cemented Paste Backfill

Libos¹,

Cui²

2020

Proceedings of the 4th International Conference on Civil, Structural and Transportation Engineering (ICCSTE'19)

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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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Effects of coupled sulphate and temperature on internal strain and strength evolution of cemented paste backfill at early age

Cited by 28 publications

References 53 publications

Preparation of Cemented Oil Shale Residue–Steel Slag–Ground Granulated Blast Furnace Slag Backfill and Its Environmental Impact

Preparation of Cemented Oil Shale Residue–Steel Slag–Ground Granulated Blast Furnace Slag Backfill and Its Environmental Impact

Mechanical Properties and Behavior of Early-Age Fiber-Reinforced 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

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