Influence of temperature on compressive strength, microstructure properties and failure pattern of fiber-reinforced cemented tailings backfill

Xu, Wenbin; Li, Qianlong; Zhang, Yalun

doi:10.1016/j.conbuildmat.2019.06.203

Cited by 72 publications

(14 citation statements)

References 43 publications

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“…In other words, there is an optimal fiber content that facilitates the shear properties of the FR-CPB/rock interface for a certain initial sulfate concentration. This result is consistent with those of previous studies performed on fiber-reinforced soils [43,55,70,71] and those conducted on fiber reinforced cementitious materials [42,56,72]. The optimal fiber content is largely dependent on its reinforcement efficiency.…”

Section: Combined Effects Of the Fiber Content And The Initial Sulfate Concentration On The Shear Behavior Of The Fr-cpb/rock Interfacesupporting

confidence: 92%

Sulfate-Dependent Shear Behavior of Cementing Fiber-Reinforced Tailings and Rock

2020

Minerals

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A better understanding of the shear behavior of the interface between cemented paste backfill (CPB) and the surrounding rock is critical for constructing cost-effective, durable, and reliable CPB structures. In practice, CPBs suffer sulfate attack during their service life, and as a typical cementitious material, the CPB itself has disadvantages, such as high brittleness, easy cracking, and insufficient durability, which restrict the further popularization and application of CPB technology. Thus, in this study, direct shear tests, electrical conductivity (EC) and thermal gravity/differential thermal gravimetric (TG/DTG) analyses were conducted to research the effects of different amounts of monofilament polypropylene fibers (0%, 0.1%, 0.3%, and 0.5%; by mass of the sum of the dry tailings and cement) and initial sulfate concentrations (0 mg/L, 5000 mg/L and 25,000 mg/L) on the shear behavior of the fiber-reinforced CPBs and rock (FR-CPB/rock) interface, and the Mohr–Coulomb shear envelop was used to fit the shear strength of specimens with various periods (1 day, 3 days, 7 days, and 28 days) under various stresses (50 kPa, 100 kPa, 150 kPa). The experimental testing results indicated that the fibers generally enhance the performance of the shear behavior of the FR-CPB/rock interface and the optimal fiber content correlates to the initial sulfate concentration. For the same treatment time (7 days), a fiber content of 0.1% contributes to the best shear performance for the FR-CPB/rock interface with a sulfate concentration of 5000 mg/L. For the sulfate-free and 25,000 mg/L concentration specimens, 0.3% is the optimal fiber content. Furthermore, for the studied interface specimens, sulfate content can play a positive (the refinement of the pore structure) or negative (the sulfate retardation effect) role in the interface shear behavior between the FR-CPB and rock, depending on the treatment time, the initial sulfate concentration, and the fiber content. For the specimens treated for 7 days and 28 days, the specimens with initial sulfate concentrations of 5000 mg/L and 25,000 mg/L achieved the highest peak shear strengths, respectively. The outcomes of this paper present a substantial reference for the design and optimization of underground FR-CPB structures under sulfate attack.

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Section: Combined Effects Of the Fiber Content And The Initial Sulfate Concentration On The Shear Behavior Of The Fr-cpb/rock Interfacesupporting

confidence: 92%

Sulfate-Dependent Shear Behavior of Cementing Fiber-Reinforced Tailings and Rock

2020

Minerals

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“…It indicated that the inhibition effect of ARS on cement hydration reaction is enhanced, which leads to the decrease of adhesive strength between ARS and the ARSCTB matrix, so the UCS of ARSCTB decreases. As the curing age increases, cement hydration products increase (Xu et al, 2019b), which can also be found in Figure 6B (the diffraction peak intensity of hydration products increases), and it can be seen from Figure 6B that the diffraction peak intensities of hydration products of CTB and ARSCTB have no obvious difference. It indicated that with the increase in curing age, the inhibition effect of ARS on cement hydration reaction is weakened.…”

Section: Resultsmentioning

confidence: 53%

Effect of the Alkalized Rice Straw Content on Strength Properties and Microstructure of Cemented Tailings Backfill

et al. 2021

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The tailings and rice straw are waste by-products, and the storage of tailings on the ground and the burning of rice straws will seriously damage the ecological environment. In this study, the effect of different contents of alkalized rice straw (ARS; rice straw was alkalized with 4% NaOH solution) on the mechanical properties and microstructure of cemented tailings backfill (CTB; ARSCTB) was studied through uniaxial compressive strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests. The results indicated that 1) the UCS of ARSCTB could be improved by ARS. However, with the increase in the ARS content from 0.1 to 0.4 wt%, the UCS showed a monotonous decreasing trend. The UCS improvement effect was best when the ARS content was 0.1 wt%, and at 7, 14, and 28 days curing ages, the UCS increased rate was 6.0, 8.3, 14.7% respectively. 2) The tensile strength of ARSCTB was generally higher than that of CTB and positively correlated with the ARS content. The tensile strength increase rate was 24.1–34.2% at 28 days curing age. 3) The SEM test indicated that the ARS was wrapped by cement hydration products, which improves its connection with the ARSCTB matrix. ARS performed a bridging role, inhibited cracks propagation, and provided drag or pulling force for the block that is about to fall off. Therefore, the mechanical properties of ARSCTB were enhanced. However, under high ARS content, the inhibition of ARS on hydration reaction and the overlap between ARS were not conducive to the improvement of the UCS of ARSCTB. 4) The post-peak residual strength and integrity effect of ARSCTB were greater. It is recommended to add 0.1–0.2 wt% ARS to the backfill with high compressive strength requirements such as the empty field subsequent filling mining method and the artificial pillar. 0.3–0.4 wt% ARS is incorporated into backfill with high tensile strength requirements such as high-stage filling with lateral exposure and artificial roof. This study further makes up for the blank of the application of plant fiber in the field of mine filling and helps to improve the mechanical properties of backfill through low-cost materials.

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“…Therefore, scientists pay considerable attention to the microstructural characterization of concrete. The literature review has revealed many articles focused on the study of microstructures present in fibre-reinforced concrete by means of several techniques, such as scanning electron microscopy (SEM) [ 28 , 120 , 121 , 122 ], energy dispersive spectroscopy (EDS) [ 123 ], X-ray diffraction analysis (XRD) [ 26 , 120 , 121 , 124 , 125 ], infrared absorption spectroscopy (IR) [ 123 ], Fourier transform infrared spectroscopy (FTIR) [ 120 , 123 ] and thermogravimetry analyses (TGA) [ 124 ].…”

Section: Fibresmentioning

confidence: 99%

Concrete Strengthening by Introducing Polymer-Based Additives into the Cement Matrix—A Mini Review

2021

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The modern types of concrete are a mixture of aggregates, cement, water and optional additives and admixtures. In particular, polymer additives seem to be a promising type of component that can significantly change concrete and mortar properties. Currently, the most popular polymer additives include superplasticizers, latexes and redispersible powders. Moreover, in order to improve the properties of concrete-based composite admixtures, which enhance the resistance to cracking, polymer fibres and recycled polymers have been researched. All the types of polymeric materials mentioned above are broadly used in the construction industry. This work summarizes the current knowledge on the different types of popular polymeric additives. Moreover, it describes the correlation between the chemical structure of additives and the macro-behaviour of the obtained concrete.

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Influence of temperature on compressive strength, microstructure properties and failure pattern of fiber-reinforced cemented tailings backfill

Cited by 72 publications

References 43 publications

Sulfate-Dependent Shear Behavior of Cementing Fiber-Reinforced Tailings and Rock

Sulfate-Dependent Shear Behavior of Cementing Fiber-Reinforced Tailings and Rock

Effect of the Alkalized Rice Straw Content on Strength Properties and Microstructure of Cemented Tailings Backfill

Concrete Strengthening by Introducing Polymer-Based Additives into the Cement Matrix—A Mini Review

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