Carbon nanotube reinforced cementitious tailings composites: Links to mechanical and microstructural characteristics

Zhang, Huan; Cao, Shuai; Yılmaz, Erol

doi:10.1016/j.conbuildmat.2022.130123

Cited by 29 publications

(4 citation statements)

References 75 publications

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“…The evident density decline slowed as the cycle generation was exceeded three times. Meanwhile, the apparent density of the MWRFA was more significant compared to the RFA with the same number of cycles, and decreased when the number of cycle generations increased, partly because of the filling effect of MWCNTs on the concrete interfacial transition zones, pores, and cracks [44], with improved densification of the matrix. Figure 4b also shows the crushing values of different aggregates.…”

Section: Effect Of Mwcnts On Multi-generational Recycled Reactive Pow...mentioning

confidence: 98%

Effects of Multi-Walled Carbon Nanotubes and Recycled Fine Aggregates on the Multi-Generational Cycle Properties of Reactive Powder Concrete

Wu,

Liu,

et al. 2024

Sustainability

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In order to investigate the effect of multi-walled carbon nanotubes (MWCNTs) on the recyclable properties of multi-generation recycled concrete, the physical properties of multi-generation recycled fine aggregate and the mechanical properties of multi-generation recycled concrete with different dosages of MWCNTs were tested, and the enhancement mechanism was analyzed by scanning electron microscopy (SEM). The results showed that the apparent density of multi-generation recycled fine aggregate with 0.05 wt% MWCNTs was increased by 1.04~2.03%, the crushing value was decreased by 38.21~49.45%, the compressive strength of the concrete prepared by it was increased by 11.11~18.96%, the splitting tensile strength was increased by 10~43.94%, the flexural strength was increased by 13.62~22.23%, and the mechanical properties were analyzed by scanning electron microscopy (SEM). Combined with the scanning electron microscope image analysis, the MWCNTs can fill the pores inside the specimen, bridge the cracks, and retard the decrease in concrete strength after multi-generation recycling.

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Section: Effect Of Mwcnts On Multi-generational Recycled Reactive Pow...mentioning

confidence: 98%

Effects of Multi-Walled Carbon Nanotubes and Recycled Fine Aggregates on the Multi-Generational Cycle Properties of Reactive Powder Concrete

Wu,

Liu,

et al. 2024

Sustainability

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“…Table 1 indicates tailings/cement products' main oxide compositions. Low-elastic-modulus fibers can be employed in various functions in CTB, depending on their type, content, and length, and each parameter seriously affects its strength and stability behavior [64]. In this study, fiber-reinforced CCTBs were made up of PP fibers alone.…”

Section: Cement Gold Tails and Watermentioning

confidence: 99%

Polypropylene Fiber’s Effect on the Features of Combined Cement-Based Tailing Backfill: Micro- and Macroscopic Aspects

Li,

Cao,

Yilmaz

2024

Minerals

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In undercut-and-fill mining, backfills show weak tensile strength and poor ductility properties since they act as artificial pillars to support stope roofs. Hence, the enhancement of the stability of mining structures and backfills is a crucial requisite for underground mining backfill operations. This study addresses the reinforcing effect of polypropylene (PP) on the strength features of combined cement-based tailing backfill (CCTB) with varied cement/tail ratios (c/t: 1:8 to 1:4) at both macroscopic and microscopic levels. Fill specimens containing a fixed solid content of 70 wt% were reinforced with fiber (0.6 wt%) and with no fiber (classified as a reference sample). They were then cast in mold sizes of 160 × 40 × 40 mm3, and cured for 7 days. Following curing, some experiments covering three-point bending assisted by DIC and SEM were performed to inspect the microstructure and strength features of CCTB. The results illustrate that the flexural strength of fiber-oriented CCTB increases along with the c/t fraction, but it is not greater than that of specimens with a high c/t fraction without fiber. Adding PP fiber, the peak deflection of CCTB specimens was improved, and the increment of peak deflection increased linearly with rising c/t fraction, enhancing CCTB’s bending characteristics. CCTB damage starts from the bottom to the middle, and the main cause of the damage is the stress distribution at the lowest section. The addition of fiber to CCTBs increases the ability to dissipate energy, which helps to hinder crack extension and prevent brittle damage from occurring. The microstructure shows that AFt and CSH were key hydrate materials in CCTB. As a result, this study develops the security of mining with backfill and helps to determine its design properties for safe production inputs and sustainable filling operations.

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“…Results indicated that CTBs with 25-30% waste rock had better flowability than others. Some researchers [70,71] also quantified that fibers were able to importantly inhibit the rapid extension of the cracks observed within CTB specimens based on SEM micrograph observations. This work firstly aims to investigate the impact of length and content of polypropylene fiber (PF) on quality and properties of fiber-reinforced cemented tailings-waste rock fill (FRCTWRF).…”

Section: Introductionmentioning

confidence: 99%

Effect of Content and Length of Polypropylene Fibers on Strength and Microstructure of Cementitious Tailings-Waste Rock Fill

2023

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The mechanical strength properties of cemented tailings backfill are very important for the safe and environmentally friendly mining of mineral resources. To check the impact of polypropylene fiber on strength and microstructure of cementitious tailings waste rock fill (CTWRF), diverse fiber lengths (6 and 12 mm) and dosages (0-control specimen, 0.3, 0.6, and 0.9 wt.%) were considered to prepare fiber-reinforced CTWRF (FRCTWRF) matrices. Experiments such as UCS (uniaxial compressive strength), X-ray CT (computed tomography), and SEM (scanning electron microscopy) were implemented to better characterize the backfills studied. Results showed that UCS performance of FRCTWRF was the highest (0.93 MPa) value at 6 mm fiber long and 0.6 wt.% fiber content. The peak strain of FRCTWRF was the highest (2.88%) at 12 mm fiber long and 0.3 wt.% fiber content. Growing the length of fiber within FRCTWRF can reduce its fracture volume, enhancing the crack resistance of FRCTWRF. Fiber and FRCTWRF are closely linked to each other by the products of cement hydration. The findings of this work will offer the efficient use of FRCTWRF in mining practice, presenting diverse perspectives for mine operators and owners, since this newly formed cementitious fill quickens the strengths required for stope backfilling.

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Carbon nanotube reinforced cementitious tailings composites: Links to mechanical and microstructural characteristics

Cited by 29 publications

References 75 publications

Effects of Multi-Walled Carbon Nanotubes and Recycled Fine Aggregates on the Multi-Generational Cycle Properties of Reactive Powder Concrete

Effects of Multi-Walled Carbon Nanotubes and Recycled Fine Aggregates on the Multi-Generational Cycle Properties of Reactive Powder Concrete

Polypropylene Fiber’s Effect on the Features of Combined Cement-Based Tailing Backfill: Micro- and Macroscopic Aspects

Effect of Content and Length of Polypropylene Fibers on Strength and Microstructure of Cementitious Tailings-Waste Rock Fill

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