scholarly journals Rheological Properties and Flow Behaviour of Cement-Based Materials Modified by Carbon Nanotubes and Plasticising Admixtures

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 169
Author(s):  
Gintautas Skripkiunas ◽  
Ekaterina Karpova ◽  
Joana Bendoraitiene ◽  
Irmantas Barauskas
Keyword(s):  
Carbon Nanotubes ◽  
Rheological Properties ◽  
Yield Stress ◽  
Cement Paste ◽  
Shear Thickening ◽  
Plastic Viscosity ◽  
Flow Behaviour ◽  
Volume Coefficient ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this study, the rheological properties of cement paste modified by a suspension containing both multi-walled carbon nanotubes (MWCNT) and carboxymethyl cellulose (CMC) (MWCNT/CMC suspension) with different types of plasticising admixtures (Pl), such as lignosulphonate (LS), sulfonated naphthalene formaldehyde condensate (NF), and polycarboxylate ether (PCE) were evaluated. The increase in yield stress and plastic viscosity up to 20% was established in the case of the modification of cement-based mixtures by MWCNT in the dosage up to 0.24% by weight of cement (bwoc) without Pl and with LS and NF. The complex modification of cement paste by MWCNT and PCE increases the yield stress and plastic viscosity from the MWCNT dosage of 0.06% and 0.015% bwoc, respectively. The yield stress and plastic viscosity of cement paste with PCE enhanced by 265% and 107%, respectively, in a MWCNT dosage of 0.12% bwoc. MWCNT do not have a significant influence on the flow behaviour index of cement paste; however, in the case of usage of PCE, the shear thickening effect decreased from a MWCNT dosage of 0.03% bwoc. The significant reduction in the volume coefficient of water bleeding by 99, 100, and 83% was obtained with LS, NF, and PCE, respectively, with an increase in MWCNT dosage up to 0.24% bwoc.

scholarly journals Degree of MWCNT suspension dispersity and its influence on rheology of cement pastes

2019 ◽  
Author(s):  
Gintautas Skripkiunas ◽  
Ekaterina Karpova ◽  
Joana Bendoraitiene ◽  
Irmantas Barauskas ◽  
Rostislav Drochytka
Keyword(s):  
Rheological Properties ◽  
Cement Paste ◽  
Rheological Behaviour ◽  
Cement Pastes ◽  
Number Of Factors ◽  
Volume Coefficient ◽  
Multi Walled Carbon Nanotubes ◽  
Homogenization Methods ◽  
Walled Carbon Nanotubes ◽  
Polycarboxylate Ether

Modification of cement pastes by MWCNT (multi-walled carbon nanotubes) suspension enables to manage by their rheological properties due to the nanometer size of MWCNT. Dispersity degree of MWCNT suspension may be determined by the number of factors such as type and intensity of homogenization equipment, duration of homogenization and some other. The aim of present research consists in the establishment of optimal methodology of MWCNT suspension homogenization and investigation of dependence between dispersity degree of MWCNT suspension and rheological properties of cement pastes with that suspension. Two types of homogenization methods of MWCNT were tested such as ultrasonication and homogenization based on rotor-stator principle. The ultrasonication treatment about 6 min was established as optimal homogenization technique in the course of the current research. The yield stress and plastic viscosity of cement paste modified by MWCNT suspension increased in comparison with cement paste modified by polycarboxylate ether plasticizer (PCE) in 5 and 30 min after cement pastes mixing.Time of ultrasonication of MWCNT suspension more than 6 min did not have the influence on rheological behaviour of cement pastes.Addition of MWCNT decreased the volume coefficient of water bleeding of cement paste with PCE by 18%.

Study of Rheological Properties of Carbon Nanotube-Reinforced Ultrafine Cement Grouting Materials

2021 ◽  
pp. 1-44
Author(s):  
Yunxiao Liu ◽  
Jiahang Zhang ◽  
Yinyin Chi
Keyword(s):  
Carbon Nanotubes ◽  
Rheological Properties ◽  
Polyvinyl Pyrrolidone ◽  
Cement Grouting ◽  
Grouting Material ◽  
Multi Walled Carbon Nanotubes ◽  
Different Diameters ◽  
Grouting Materials ◽  
Walled Carbon Nanotubes ◽  
Ultrafine Cement

In this study, three different diameters of multi-walled carbon nanotubes (MWCNTs) dispersed by polyvinyl pyrrolidone (PVP) were used to reinforce superfine cement grouting materials. The effect of MWCNTs and polyvinyl pyrrolidone (PVP) on the rheological properties of grouting material were accordingly studied. It was found that the yield stress (τ0) and plastic viscosity (η) were slightly decreased when PVP content was low and increased when the PVP content increased. The effect of MWCNT diameter on τ0 was not found to be clear but was more significant on η. The smaller MWCNT diameter was, the more quickly η increase. It was also found that the thixotropic ring area was increased as the MWCNTs content increased. The addition of PVP and MWCNTs caused an increase in the number of entanglement points in different scales, which was the main reason for the viscosity and thixotropy increase. Therefore, the rheological properties of superfine cement grouting material should be adjusted when MWCNTs were added as a reinforcing component. Due to the wrapping of PVP on cement particles which isolates the contacting part between the water and the cement particles, it slows down the cement's hydration rate thus slows down the fluidity loss of the slurry.

β-nucleated propylene–ethylene random copolymer filled with multi-walled carbon nanotubes: Mechanical, thermal and rheological properties

Polymer ◽  
2014 ◽  
Vol 55 (16) ◽  
pp. 3758-3769 ◽  
Author(s):  
Dimitrios G. Papageorgiou ◽  
Lazaros Tzounis ◽  
George Z. Papageorgiou ◽  
Dimitrios N. Bikiaris ◽  
Konstantinos Chrissafis
Keyword(s):  
Carbon Nanotubes ◽  
Rheological Properties ◽  
Random Copolymer ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

scholarly journals Shear-Thickening Fluid Using Oxygen-Plasma-Modified Multi-Walled Carbon Nanotubes to Improve the Quasi-Static Stab Resistance of Kevlar Fabrics

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1356 ◽  
Author(s):  
Danyang Li ◽  
Rui Wang ◽  
Xing Liu ◽  
Shu Fang ◽  
Yanli Sun
Keyword(s):  
Carbon Nanotubes ◽  
Loss Modulus ◽  
Shear Thickening ◽  
Woven Fabrics ◽  
Body Armor ◽  
Shear Thickening Fluid ◽  
Pull Out ◽  
Stab Resistance ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The excellent mechanical property and light weight of protective materials are vital for practical application in body armor. In this study, O2-plasma-modified multi-walled carbon nanotubes (M-MWNTs) were introduced into shear-thickening fluid (STF)-impregnated Kevlar woven fabrics to increase the quasi-static stab resistance and decrease the composite weight. The rheological test showed that the addition of 0.06 wt. % M-MWNT caused a marked increase in the peak viscosity from 1563 to 3417 pa·s and a decrease in the critical shear rate from 14.68 s−1 to 2.53 s−1. The storage modulus (G′) and loss modulus (G″) showed a higher degree of abrupt increase with the increase of shear stress. The yarn pull-out test showed that the yarn friction of M-MWNT/STF/Kevlar fabrics was far superior to the original fabrics. Importantly, under similar areal density, the M-MWNT/STF/Kevlar fabrics could resist 1261.4 N quasi-static stab force and absorb 41.3 J energy, which were much higher than neat Kevlar fabrics. The results of this research indicated that quasi-static stab resistance was improved by M-MWNTs, which was attributed to the excellent shear-thickening effect and the high yarn friction. Therefore, M-MWNT/STF/Kevlar fabrics have a broad prospect in the fields of body protection.

The effect of multi-walled carbon nanotubes on the rheological properties and hydration process of cement pastes

2018 ◽  
Vol 189 ◽  
pp. 947-954 ◽  
Author(s):  
Dainius Leonavičius ◽  
Ina Pundienė ◽  
Giedrius Girskas ◽  
Jolanta Pranckevičienė ◽  
Modestas Kligys ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Rheological Properties ◽  
Hydration Process ◽  
Cement Pastes ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

scholarly journals Influence of Nano-SiO2, Nano-CaCO3 and Nano-Al2O3 on Rheological Properties of Cement–Fly Ash Paste

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2598 ◽  
Author(s):  
Yiming Peng ◽  
Kunlin Ma ◽  
Guangcheng Long ◽  
Youjun Xie
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Yield Stress ◽  
Free Water ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Plastic Viscosity ◽  
Behavior Changes ◽  
Nano Sio2 ◽  
Resting Time

Rheological curves of cement–fly ash (C–FA) paste incorporating nanomaterials including nano-SiO2 (NS), nano-CaCO3 (NC) and nano-Al2O3 (NA) at different resting times (hydration time of 5 min, 60 min, and 120 min) were tested with a rheometer. The rheological behaviors were described by the Herschel–Bulkley (H–B) model, and the influences of these nanomaterials on rheological properties of C–FA paste were compared. Results show that the types, content of nanomaterials and resting time have great influences on the rheological properties of C–FA paste. Incorporating NS and NA increases yield stress and plastic viscosity, and decreases the rheological index of C–FA paste. When the content of NS and NA were 2 wt%, the rheological index of C–FA paste was less than 1, indicating rheological behavior changes from shear thickening to shear thinning. Meanwhile, with rising resting time, yield stress and plastic viscosity increased significantly, but the rheological index decreased evidently, showing paste takes on shear thinning due to the rise of resting time. However, incorporating 3 wt% NC and the rising of resting time did not change the rheological properties of C–FA paste. These differences are mainly that the specific surface area (SSA) of NS (150 m2/g) and NA (120 m2/g) are much larger than that of NC (40 m2/g). The huge SSA of NS and NA consume lots of free water and these tiny particles accelerate the hydration process during resting time.

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