scholarly journals Effect of Graphene Oxide on Mechanical Properties of Cement Mortar and its Strengthening Mechanism

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3753 ◽  
Author(s):  
Yahui Wang ◽  
Jiawen Yang ◽  
Dong Ouyang
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Cement Hydration ◽  
Strengthening Mechanism ◽  
Cement Composites ◽  
Working Mechanism ◽  
Cement Pastes ◽  
Cement Mortars ◽  
Binder Ratio ◽  
Growth Space

The effects of the water–binder ratio and different graphene oxide (GO) sizes on the mechanical properties of GO-cement composites were systematically studied by preparing GO-cement mortars. The scanning electron microscopy observation (SEM) of the surface and fracture surface of cement pastes was carried out to study the morphology of cement hydration crystals in GO-cement systems under different space conditions. It was found that GO nanosheets significantly improved the compressive, flexural, and tensile strengths of cement mortars. When the dosage of GO nanosheets was 0.03% by weight of cement, the compressive, flexural, and tensile strengths at 28 days increased by 21.37%, 39.62%, and 53.77%, respectively, but GO was not found to be able to regulate the formation of flower-like cement hydration crystals. It was only shown that the growth space had an important influence on the morphology of hydrates. A possible working mechanism was proposed by which GO nanosheets prevented the expansion of microcracks in the cement pastes via a shield effect, thus enhancing the strength and toughness of the cement composites.

Effect of Nano-Silica Particles on the Fresh Properties of UHPC

2014 ◽  
Vol 629-630 ◽  
pp. 91-95
Author(s):  
Qian Qian Zhang ◽  
Jian Zhong Liu ◽  
Wei Lin
Keyword(s):  
Mechanical Properties ◽  
Cement Hydration ◽  
Physical And Mechanical Properties ◽  
Heat Evolution ◽  
Fresh Properties ◽  
Nano Silica ◽  
Cement Pastes ◽  
Binder Ratio ◽  
Nanosilica Particles ◽  
Water Binder Ratio

Nanotechnology is being used in UHPC for achieving more dense structural packing and better physical and mechanical properties. In this paper, nanosilica particles (0-1wt %) by cement were incorporated in cement pastes and mortars with water-binder ratio of 0.2, and their effect on fresh properties was addressed. The fresh properties of mixtures were investigated by spread, rheology and cohesiveness. In addition, effect of nanosilica on cement hydration was also investigated. The results show that significant increase of yield stress, viscosity and cohesiveness is observed with nanosilica above 0.005 wt% by cement, but nanosilica with content below 0.005% presents an improvement of workability especially with content of 0.002%. Moreover, the addition of nanosilica in cement pastes obviously accelerates the early cement hydration rate, but does not increase the cumulative heat evolution.

scholarly journals Preparation and Mechanical Properties of Graphene Oxide: Cement Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fakhim Babak ◽  
Hassani Abolfazl ◽  
Rashidi Alimorad ◽  
Ghodousi Parviz
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Cement Composites ◽  
Xrd Diffraction ◽  
Calcium Silicate Hydrates ◽  
The Matrix ◽  
Scanning Electron

We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

scholarly journals Effect of Graphene Oxide/Graphene Hybrid on Mechanical Properties of Cement Mortar and Mechanism Investigation

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 113 ◽  
Author(s):  
Hongfang Sun ◽  
Li Ling ◽  
Zhili Ren ◽  
Shazim Ali Memon ◽  
Feng Xing
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Pore Size Distribution ◽  
Cement Mortar ◽  
Underlying Mechanism ◽  
Mortar Specimen ◽  
Degree Of Hydration ◽  
Cement Mortars

This paper evaluated the effect of graphene oxide/graphene (GO/GR) hybrid on mechanical properties of cement mortar. The underlying mechanism was also investigated. In the GO/GR hybrid, GO was expected to act as a dispersant for GR while GR was used as reinforcement in mortar due to its excellent mechanical properties. For the mortar specimen, flexural and compressive strength were measured at varied GO to GR ratios of 1:0, 3:1, 1:1, 1:3, and 0:1 by keeping the total amount of GO and GR constant. The underlying mechanism was investigated through the dispersibility of GR, heat releasing characteristics during hydration, and porosity of mortar. The results showed that GO/GR hybrid significantly enhanced the flexural and compressive strength of cement mortars. The flexural strength reached maximum at GO:GR = 1:1, where the enhancement level was up to 23.04% (28 days) when compared to mortar prepared with only GO, and up to 15.63% (7 days) when compared to mortar prepared with only GR. In terms of compressive strength, the enhancement level for GO:GR = 3:1 was up to 21.10% (3 days) when compared with that of mortar incorporating GO only. The enhancement in compressive strength with mortar at GO:GR = 1:1 was up to 14.69% (7-day) when compared with mortar incorporating GR only. In addition to dispersibility, the compressive strength was also influenced by other factors, such as the degree of hydration, porosity, and pore size distribution of mortar, which made the mortars perform best at different ages.

Experimental and Modeling Studies on Thermal Conductivity of Cement Composites Containing Nanosilica

2014 ◽  
Vol 979 ◽  
pp. 119-123
Author(s):  
Pongsak Jittabut ◽  
Prinya Chindaprasirt ◽  
Supree Pinitsoontorn
Keyword(s):  
Thermal Conductivity ◽  
Cement Paste ◽  
Building Energy ◽  
Cement Composites ◽  
Building Energy Efficiency ◽  
Cement Pastes ◽  
Research Article ◽  
Binder Ratio ◽  
Nanosilica Particle ◽  
Water To Binder Ratio

This research article was presented the thermal conductivity of cement pastes containing nanosilica. The effects of nanosilica particle size and concentration determined by mixing three nanosilica particle sizes of 12, 50 and 150 nm, using nanosilica were of 1-5 wt%. The water to binder ratio of 0.5 was used. The thermal properties test were subsequently measured in terms of thermal conductivity coefficient using ISOMET 2114. The thermal conductivities of cement paste is thus numerically calculated and the predictions are compared with the existing experimental data. A unifying equation for four fundamental effective thermal conductivity structural models (Series, Parallel, one-dimensional heat flow, Maxwell’s model) was derived. The best prediction was provided by a composite model that combined the Maxwell’s model. Consequently, applications of nanosilica cement paste in building constructions may be an interesting solution in order to improve sustainability and building energy efficiency.

scholarly journals Quantifying the Difference of Uniformly Dispersed and Re-agglomerated Graphene Oxide-Based Cement Pastes on Rheological and Mechanical Properties

2018 ◽  
Vol 206 ◽  
pp. 03003
Author(s):  
Haodao Li ◽  
Jingjie Wei ◽  
Wujian Long
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Large Diameter ◽  
Cement Pastes ◽  
The Difference ◽  
Compressive And Flexural Strengths ◽  
Porosity Analysis ◽  
Better Than

The state of GO dispersion is closely related to the properties of graphene oxide (GO)-based cement paste. This paper presents the effect of uniformly dispersed and re-agglomerated GO on the rheological and mechanical properties. The results showed that, compared to re-agglomerated GO cement paste, the yield stress and plastic viscosity of uniformly dispersed GO cement paste were higher. Moreover, the compressive and flexural strengths of uniformly dispersed GO pastes were higher than those of re-agglomerated GO pastes. Porosity analysis using mercury intrusion porosimetry showed that the well-dispersed GO can inhibit the formation of large-diameter pores and optimize the pore size distribution better than the re-agglomerated GO.

scholarly journals Effect of Delaminated MXene (Ti3C2) on the Performance of Cement Paste

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jianping Zhu ◽  
Genshen Li ◽  
Chunhua Feng ◽  
Libo Wang ◽  
Wenyan Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Paste ◽  
Cement Hydration ◽  
Hydration Heat ◽  
Hydration Process ◽  
Cement Matrix ◽  
Cement Composites ◽  
Hydrated Cement ◽  
Hydration Products

Delaminated MXene was incorporated into cement to improve the properties of cement composites, and its effects on the hydration process, microstructures, and mechanical properties were investigated, respectively. The investigation results showed that delaminated MXene was well-dispersed in the cement matrix and significantly reinforced the compressive strength of cement, especially when the addition is 0.01 wt%. Meanwhile, the total hydration heat of cement hydration and the quantity of hydration products were increased with the addition of delaminated MXene. In addition, the formation of HD C-S-H gel was promoted, and the microstructure of hydrated cement became more compact.

Effect of SRA on the Course of Hydration of Cement Composites

2019 ◽  
Vol 296 ◽  
pp. 35-40
Author(s):  
Lucia Osuská ◽  
Martin Ťažký ◽  
Milan Meruňka ◽  
Rudolf Hela
Keyword(s):  
Liquid Phase ◽  
Chemical Reaction ◽  
Cement Hydration ◽  
Cement Composites ◽  
Mechanical Parameters ◽  
Curing Time ◽  
Volume Changes ◽  
Cement Pastes ◽  
Binder Component ◽  
The Impact

Cement hydration is a chemical reaction that is associated with the development of hydration heat and changes in the volume of input components that transit from the solid and liquid phase to one homogeneous whole. In order to eliminate the volume changes already occurring during the hydration process, several principles can be applied, such as the use of active or inert admixtures as partial cement substitute or special shrinkage reducing additives. The experiment verifies the effect of anti-shrinkage additives on the course of hydration of cement pastes in terms of the development of hydration temperatures and elimination of volume changes of cement pastes. Volume changes will be monitored for the first 30 hours of cement mixing with water, i.e. in the time when the major changes occur due to this chemical reaction. Due to the expected hydration deceleration of the binder component by the effect of SRA, the impact of the use of these additives on the curing time of the composite and consequently on the mechanical parameters of the concrete will be verified.

scholarly journals Propiedades mecánicas de morteros de cemento con adiciones de fibras de carbono, nanotubos de carbono y grafeno = Mechanical properties of cement mortars with additions of carbon fibres, carbon nanotubes and graphene

2017 ◽  
Vol 3 (3) ◽  
pp. 12
Author(s):  
María Ursúa Goicoechea
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Carbon Fibers ◽  
Carbon Materials ◽  
Carbon Fibres ◽  
Cement Mortars ◽  
Different Types ◽  
Cement Matrices ◽  
Cement Compounds

El carbono es uno de los elementos más abundantes de la naturaleza. Su particular estructura hace que pueda tener hasta cinco tipos distintos de alótropos. Durante los últimos años se han producido grandes avances en el estudio de estos materiales de carbono. Las fibras de carbono (CF), los nanotubos de carbono (CNTs) y el grafeno y óxido de grafeno (GO), en función de su estructura y su escala, presentan unas propiedades notablemente diferenciadas. Este estudio pretende comparar y determinar los efectos de estas características en matrices de cemento. Las características de estos materiales son difíciles de transmitir de forma exacta a los compuestos de cemento y hormigones, principalmente por las dificultades que presentan los nanomateriales en su dispersión. Por ello, los datos obtenidos en distintos estudios muestran resultados muy variables. Sin embargo, se ha demostrado que, para mejoras medias, los nanomateriales resultan ser más eficientes.AbstractCarbon is one of the most abundant elements of nature. Its particular structure has to have up to five different types of allotropes. During the last years there have been great advances in the study of these carbon materials. Carbon fibers (CF), carbon nanotubes (CNT) and graphene and graphene oxide (GO), depending on their structure and scale, have remarkably different properties. This study aims to compare and determine the effects of these characteristics on cement matrices. The characteristics of these materials are difficult to transmit accurately to concrete and cement compounds, mainly due to the difficulties presented by nanomaterials in their dispersion. Therefore, the data obtained in different studies, results, very variable. However, it has been shown that, for average improvements, nanomaterials are more efficient.

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