Study on the three dimensional mechanism of graphene oxide nanosheets modified cement

Wang, Min; Wang, Rumin; Yao, Hao; Farhan, Shameel; Zheng, Shao-Fei; Du, Congcong

doi:10.1016/j.conbuildmat.2016.09.092

Cited by 161 publications

(94 citation statements)

References 47 publications

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“…[25][26][27][28][29][30][31][32][33][34] Graphene oxide is highly dispersible in water due to the oxygen functional groups attached on the basal plane and edges of GO sheets, [35] hence the main approach employed to fabricate cement-GO composites involves simply ultrasonication of GO dispersion in water, prior to mixing with cement. Therefore, cement composites incorporating graphene oxide (GO), i.e., the most easily processable graphene derivative, have been intensively investigated in recent years.…”

Section: Introductionmentioning

confidence: 99%

“…[25] Nonetheless, as revealed by recent studies, [29,31,32] the incorporation of graphene oxide dispersion into cement leads to the immediate formation of agglomerations and flocculation due to the formation of metal complexes, i.e., chemical cross-linking of GO nanosheets by calcium ions present in cement matrix. Even in the case of composites with lowered workability, where no special treatment for ensuring appropriate GO dispersion within cement matrix was applied, [25][26][27][28] the addition of GO has greatly enhanced the strength of cement paste. In order to provide the appropriate workability of composites and the sufficient dispersion of GO in alkaline cement environment, two main approaches have been proposed.…”

Section: Introductionmentioning

confidence: 99%

“…The GO aggregates entrap free water molecules, thereby affecting the rheological properties of cement mixture. The maximum increase up to 47%, 57%, and 67% has been noted for compressive, [27] flexural, [26] and indirect tensile strength, [28] respectively. The former relies on the surface modification of GO by mixing and sonication with the addition of polycarboxylate superplasticizer (PC) to prevent agglomeration of GO, by taking advantage of the strong steric hindrance effects of PC to separate GO nanosheets from Ca 2+ ions.…”

Section: Introductionmentioning

confidence: 99%

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High‐Performance Graphene‐Based Cementitious Composites

et al. 2019

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This study reports on the development of a cementitious composite incorporating electrochemically exfoliated graphene (EEG). This hybrid functional material features significantly enhanced microstructure and mechanical properties, as well as unaffected workability; thus, it outperforms previously reported cementitious composites containing graphene derivatives. The manufacturing of the composite relies on a simple and efficient method that enables the uniform dispersion of EEG within cement matrix in the absence of surfactants. Different from graphene oxide, EEG is found to not agglomerate in cement alkaline environment, thereby not affecting the fluidity of cementitious composites. The addition of 0.05 wt% graphene content to ordinary Portland cement results in an increase up to 79%, 8%, and 9% for the tensile strength, compressive strength, and Young's modulus, respectively. Remarkably, it is found that the addition of EEG promotes the hydration reaction of both alite and belite, thus leading to the formation of a large fraction of 3CaO·2SiO 2 ·3H 2 O (C‐S‐H) phase. These findings represent a major step forward toward the practical application of nanomaterials in civil engineering.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High‐Performance Graphene‐Based Cementitious Composites

et al. 2019

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“…The strengthening mechanism of GO in cement matrix is attributed to the chemical reaction between -COOH groups attached on the GO flakes and calcium ions from calcium hydroxide present in cement; thus, a 3D network structure is formed. Moreover, graphene oxide promotes and accelerates the growth of cement hydration products due to the New Uses of Micro and Nanomaterials nucleation effect [46][47][48]. As a consequence of this 3D network, the microstructure of cement composites is visibly densified with a higher crystal growth and less prominent microcracks.…”

Section: Improvement Of Mechanical Properties and Durabilitymentioning

confidence: 99%

Nanomaterials in Structural Engineering

Krystek¹,

Górski²

2018

New Uses of Micro and Nanomaterials

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Development of structural engineering, daring structures with record spans or heights, meets two serious obstacles-the limitations of traditionally used materials and the need of continuous monitoring of new structures subjected to complex loads, including those of dynamic nature. Considering the responsibility for the life of people and the budget of new structures, the need of constant monitoring is inevitable. This is why structural engineers seek for new solutions; among them, smart structures based on self-monitoring materials seem to be one of the most attractive proposals. It is still an unexplored area, but current research shows a high potential of the use of composites reinforced by carbon-based nanomaterials as self-sensing structural materials. Nanomaterials also influence other important features of structural materials, such as microstructure, mechanical, and transport-related properties. In this chapter, we present the state of art of the use of nanomaterials in structural engineering in various areas including mechanical and electrical properties as well as issues referring to durability.

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“…In recent years, numerous researchers have investigated the reinforcing effects of GO nanosheets on cement composites . The common conclusion is that GO can promote to form regular shaped cement hydration products and compact micro‐ and macro‐structure, which can obviously improve the strength and durability of the cement composites . Meanwhile, another problem is found that GO nanosheets are readily aggregate in solution and do not evenly disperse within the cement paste and presents a limitation on its usage …”

Section: Introductionmentioning

confidence: 99%

Structure, performances, and formation mechanism of cement composites with large‐scale regular microstructure by distributing uniformly few‐layered graphene oxide in cement matrix

Lei

et al. 2018

Structural Concrete

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The multiple layered graphene oxide (GO) was prepared by modified Hummer's method. Then few-layered GO was obtained by forming intercalation composites with the multiple layered GO and poly(acrylic acid-acrylamide-diallyl dimethyl ammonium chloride) (PAAD). The goal is to prepare large-scale ordered structure in the whole cement composites by distributing uniformly the GO in cement matrix. The effects of PAAD on GO nanosheets and its distribution within the cement paste were investigated and assessed by characterization of the size range of GO nanosheets and microstrcuture of cement matrix. The results showed that the GO nanosheet size can reduce to 3-110 nm from 6.5-450 nm in composites with PAAD, in contrast to 5-210 nm for polycarboxylate superplasticizers. Doping GO/PAAD intercalation composites, the large-scale ordered structural cement composites were prepared. The SEM images indicated that the whole cement composites consisted of regular cement hydration products by interweaving and crosslinking. The X-ray diffraction patterns indicated that there are new crystals in the cement composites and the amorphous hydration products have been transferred into crystal phase. The forming mechanism was proposed according to these research results. The test results indicated that the cement composites have high compressive and flexural strengths, good heat resistance, few cracks, small average pore diameter and good durability.

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Study on the three dimensional mechanism of graphene oxide nanosheets modified cement

Cited by 161 publications

References 47 publications

High‐Performance Graphene‐Based Cementitious Composites

High‐Performance Graphene‐Based Cementitious Composites

Nanomaterials in Structural Engineering

Structure, performances, and formation mechanism of cement composites with large‐scale regular microstructure by distributing uniformly few‐layered graphene oxide in cement matrix

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