Effect and mechanism analysis of functionalized multi-walled carbon nanotubes (MWCNTs) on C-S-H gel

Li, Yue; Li, Hongwen; Wang, Zigeng; Jin, Caiyun

doi:10.1016/j.cemconres.2019.105955

Cited by 49 publications

(13 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This aspect can indicate the lack of chemical interactions between nanotubes and cement hydration products. The inert character of carbon-based materials without additional functionalization was also highlighted in previous research [12,42]. MWCNTs in the bottom-left corner of the SEM image have a curved shape, which can be caused by the high differences between the diameter of the nanotubes and their length.…”

Section: Multi-walled Carbon Nanotubessupporting

confidence: 58%

“…Moreover, the interactions between the surfaces of additives and cement hydration products should be taken into consideration. In the case of carbon nanomaterials, such as nanotubes and carbon black, the inert nature of carbon does not lead to the formation of hydrates on its surface with strong adhesion between them (Figures 3, 4 and 8) [12,45]. In the case of ultrafine additives with amorphous SiO 2 , a pozzolanic reaction takes place (Figure 11) [33,34].…”

Section: Discussionmentioning

confidence: 99%

“…The additives, which work as initializers of crystallization, can affect the hydration processes and create the conditions for the formation of a structure with predefined properties. Today, there are a significant number of papers on the structuring of the cement matrix due to the effects of ultrafine additives on the morphology of cement hydration products [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Ultrafine Additives on the Morphology of Cement Hydration Products

et al. 2021

View full text Add to dashboard Cite

The present research is focused on the investigation of the influence of ultrafine additives on the structure formation of hardened cement paste and the establishment of the mechanisms of the morphological transformations, which determine the properties of hydrated products. In the course of the research, the modification of ordinary Portland cement was performed by the suspension of multi-walled carbon nanotubes (MWCNTs), carbon black (CB) paste, and silica fume (SF). Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD) analysis, thermal analysis, and Fourier-transform infrared (FTIR) spectroscopy were used to study cement hydration products. The morphology of hardened cement paste depends on the chemical reactivity of additives, their geometry, and their genesis. The action mechanism of the inert carbon-based additives and pozzolanic silica fume were considered. The cement hydration products formed in the process of modification by both types of ultrafine additives are described. In the case of the modification of cement paste by inert MWCNTs and CB paste, the formation of cement hydration products on their surface without strong adhesion was observed, whereas in the case of the addition of SF separately and together with MWCNTs, the strong adhesion of additives and cement hydration products was noted.

show abstract

Section: Multi-walled Carbon Nanotubessupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Ultrafine Additives on the Morphology of Cement Hydration Products

et al. 2021

View full text Add to dashboard Cite

show abstract

“…This paper reports the morphology and precipitation kinetics of the synthetic C-S-H formed on the surfaces of various inert fillers. The properties of the synthetic C-S-H have been investigated in prior studies [16][17][18][19][20][21][22][23][24][25]. By selecting the synthetic C-S-H as the studied target, other undesired interferences from many factors can be eliminated, such as the reaction of the aluminate phases in Portland cement and the dissolution process of alite.…”

Section: Introductionmentioning

confidence: 99%

A new understanding of the effect of filler minerals on the precipitation of synthetic C–S–H

et al. 2020

View full text Add to dashboard Cite

The filler effect is the most important physical mechanism of mineral admixtures in the early hydration of cement whose chemical properties greatly affect the precipitation of C-S-H. In this study, calcite, strontianite, magnesite, dolomite, quartz, whewellite and whitlockite were selected as the fillers. The morphology and reaction kinetics of synthetic C-S-H precipitated on the surfaces of different fillers were studied via electron microscopy observations and electrical conductivity and ion concentration measurements. The precipitation rate of C-S-H has a positive correlation with the affinity of Ca 2+ for adsorption on the fillers, which can be explained by the nucleation barrier of C-S-H. Extremely ordered honeycomb-like morphology of the C-S-H is found on calcite and strontianite surfaces, while less regular leaf-like or honeycomb-like C-S-H are found on whewellite and whitlockite. The ordered C-S-H pattern is related to the lattice cleavage of the ionic compound filler.In the case of quartz, C-S-H prefers growth along the tangential direction, which is quite different from the normal-direction growth on ionic compounds. The in-plane growth of C-S-H on quartz is believed to be induced by a layer of loosely physically-adsorbed Ca 2+ .

show abstract

“…17) It is generally considered that the metakaolinbased geopolymer (MKG) has a typical structure of the three-dimensional network and typical geopolymer characteristics. 18) There are many studies concerning the formation mechanism and affecting factors of MKG. 19)22) It is a relatively unified conclusion that the formation of MKG include two steps:(1) dissolution of a reactive silicate and aluminate monomers from the metakaoline (MK) and (2) condensation to an aluminosilicate gel.…”

Section: Introductionmentioning

confidence: 99%

Study on the microstructure of metakaolin-based geopolymer enhanced by polyacrylate

Xiao

Zhou

et al. 2019

J. Ceram. Soc. Japan

View full text Add to dashboard Cite

In order to explore the microscopic mechanism of the remarkable improvement of the organic polymer on the mechanical properties of the geopolymer, fourier transform infrared spectroscopy, 29 Si nuclear magnetic resonance, scanning electron microscope and molecular imprinted polymer were used to investigate the effects of polyacrylate (PAAS) on the microstructure of the metakaolin-based geopolymer (MKG). The load-deflection curves were also tested to confirm the toughing effect. The results show that the organic polymer can modify the structure of the geopolymer at the molecular scale and submicroscopic scale. At the molecular scale, SiOC bonds formed in MKG after the incorporation of PAAS and the polymerization degree of [SiO 4 ] tetrahedra reduced resulting in the mean chain length of [SiO 4 ]/[AlO 4 ] tetrahedra change. At the submicroscopic scale, the MKG became denser after adding PAAS because PAAS could fill the cracks and capillary pores of MKG. Also, PAAS formed a film with an interconnected network structure, which interpenetrated to geopolymer. The loaddeflection curves confirmed increase by 50% in the flexural toughness coefficient of the MKG with the incorporation of 0.8 wt % PAAS.

show abstract

Effect and mechanism analysis of functionalized multi-walled carbon nanotubes (MWCNTs) on C-S-H gel

Cited by 49 publications

References 59 publications

Effect of Ultrafine Additives on the Morphology of Cement Hydration Products

Effect of Ultrafine Additives on the Morphology of Cement Hydration Products

A new understanding of the effect of filler minerals on the precipitation of synthetic C–S–H

Study on the microstructure of metakaolin-based geopolymer enhanced by polyacrylate

Contact Info

Product

Resources

About