Flexural stress and crack sensing capabilities of MWNT/cement composites

Naeem, Faizan; Lee, Haeng‐Ki; Kim, Hyeong-Ki; Nam, I.W.

doi:10.1016/j.compstruct.2017.04.078

Cited by 73 publications

(21 citation statements)

References 35 publications

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“…Finally, because of the very high CNTs content in the PP/CNT-7 nanocomposite, even if the conductive network experience some modifications, the impedance variation is very low (∆Z = 0.26 MΩ, Table 5). With regard to repeated tests, also in the case of PP/CNT-5 and PP/CNT-7 nanocomposites, the reproducibility of the measurement and the recovery of the initial impedance value after load removal were confirmed (Figures 11b and 12b, respectively), contrarily to what reported by Naeem et al [67] for MWNT/cement composites. Indeed, even small strains are able to rearrange CNTs fillers distribution in cementitious materials, on the contrary, the advantage in the use of PP/CNT nanocomposites strips, is represented by the use of a flexible material that recover its original properties.…”

Section: Strain-sensing Testssupporting

confidence: 80%

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Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

et al. 2020

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Polypropylene/carbon nanotubes (PP/CNTs) nanocomposites with different CNTs concentrations (i.e., 1, 2, 3, 5 and 7 wt%) were prepared and tested as strain gauges for structures monitoring. Such sensors were embedded in cementitious mortar prisms and tested in 3-point bending mode recording impedance variation at increasing load. First, thermal (differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA)), mechanical (tensile tests) and morphological (FE-SEM) properties of nanocomposites blends were assessed. Then, strain-sensing tests were carried out on PP/CNTs strips embedded in cementitious mortars. PP/CNTs nanocomposites blends with CNTs content of 1, 2 and 3 wt% did not show significant results because these concentrations are below the electrical percolation threshold (EPT). On the contrary, PP/CNTs nanocomposites with 5 and 7 wt% of CNTs showed interesting sensing properties. In particular, the best result was highlighted for the PP/CNT nanocomposite with 5 wt% CNTs for which an average gauge factor (GF) of approx. 1400 was measured. Moreover, load-unload cycles reported a good recovery of the initial impedance. Finally, a comparison with some literature results, in terms of GF, was done demonstrating the benefits deriving from the use of PP/CNTs strips as strain-gauges instead of using conductive fillers in the bulk matrix.

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Section: Strain-sensing Testssupporting

confidence: 80%

“…Indeed, each sample was loaded and unloaded three times to verify measurements reproducibility and possible decay of the self-sensing ability over the time. Specimens strain (ε) was calculated according to [67], using Equation 2:…”

Section: Strain-sensing Testsmentioning

confidence: 99%

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

et al. 2020

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“…Although a number of papers have been reported on the flexural performance of binary nanosilica [34], nanotube [35], or nanoclay [36] enhanced cements, no research has been presented in ternary blends reinforced with fibers. It is acknowledged that nMt nanoparticles can improve flexural strength and assign damping properties [37] to pastes they will be added to [19].…”

Section: Manufacturing and Fabrication Methods Cement MIX Characterizamentioning

confidence: 99%

From Nanostructural Characterization of Nanoparticles to Performance Assessment of Low Clinker Fiber–Cement Nanohybrids

Paine

2019

Applied Sciences

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With the current paper three nano-Montmorillonites (nMt) are applied in cement nanohybrids: an organomodified nMt dispersion, nC2; an inorganic nMt dispersion, nC3; and an organomodified powder, nC4. nC4 is fully characterized in this paper (X-ray diffraction, scanning electron microscopy/X-ray energy dispersive spectroscopy and thermal gravimetric analysis/differential thermogravimetry. Consecutively a ternary non pozzolanic combination of fiber–cement nanohybrids (60% Portland cement (PC) and 40% limestone (LS)) was investigated in terms of flexural strength, thermal properties, density, porosity, and water impermeability. Flexural strength was improved after day 28, particularly with the addition of the inorganic nMt dispersion. There was no change in density or enhancement in pozzolanic reactions for the powder nMt. Mercury intrusion porosimetry showed that the pore related parameters were increased. This can be attributed to mixing effects and the presence of fibers. Water impermeability tests yielded ambiguous results. Clearly, novel manufacturing processes of cement nanohybrids must be developed to eliminate mixing issues recorded in this research.

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“…(63) developed an improved analytical model based on IPD (Inter particle distance) to predict the percolation threshold 'P c ' (%) of graphite nano platelets with high aspect ratio in the polymer composites. His proposed equation [9] is as follows and the computed values for the present study are presented in Table 5:…”

Section: Theoretical Calculations and Analysismentioning

confidence: 99%

“…Fiber reinforced cementitious composites (FRCCs) are gaining importance for their superior mechanical, electrical and chemical properties. Although the history of fibers utilization in composites dates back to 1500 BC but in recent years many new types of synthetic fibers have been developed and being utilized along with natural fibers such as polypropylene (PP), polyvinyl alcohol (PVA), steel, glass, carbon fibers (CFs) and carbon nanotubes (CNTs) (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). Among synthetic fibers, CFs possess exceptional physical and mechanical characteristics; therefore, they are being used as reinforcement to augment the mechanical properties (i.e.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental analysis of multifunctional high performance cement mortar matrices reinforced with varying lengths of carbon fibers

et al. 2018

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An effective scheme to formulate high performance and multifunctional cement based mortar composites reinforced with varying lengths of carbon fibers has been devised. The detailed investigations pertaining to the fracture response of composites in cracks initiation and progression phases, their conducting mechanism and volumetric stability were performed with varying loads of 6mm and 12mm long carbon fibers at two different w/c ratios i.e. 0.45 and 0.50. The experiments concluded that an optimum addition of carbon fibers results in substantial improvement of fracture properties alongside significant reduction in electrical resistivity and total plastic shrinkage. The field emission scanning electron microscopy of the cryofractured specimen revealed crack arresting actions of uniformly distributed carbon fibers through successful crack bridging and branching phenomenon.

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Flexural stress and crack sensing capabilities of MWNT/cement composites

Cited by 73 publications

References 35 publications

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

From Nanostructural Characterization of Nanoparticles to Performance Assessment of Low Clinker Fiber–Cement Nanohybrids

Theoretical and experimental analysis of multifunctional high performance cement mortar matrices reinforced with varying lengths of carbon fibers

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