Design of SiO 2 /PMHS hybrid nanocomposite for surface treatment of cement-based materials

Li, Ran; Hou, Pengkun; Xie, Ning; Ye, Zhengmao; Cheng, Xin; Shah, Surendra P.

doi:10.1016/j.cemconcomp.2017.12.008

Cited by 70 publications

(21 citation statements)

References 44 publications

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“…Furthermore, the concentration and type of the active substance in the agent constitute a very crucial factor. In the literature, there can be noted examples of different additives and admixtures that can be used for hydrophobisation, such as superhydrophobic nano-silica [29], particle-siloxane [31], silica particles in rice husk ash modified using fluoroalkyl silane [30], methyl-silicon resin [36], alkyl-alkoxy-siloxane [36], SiO 2 -CH 3 submicron-sized [38], alkyl-alkoxy-siloxane oligomer and methyl silicone resin in an organic solvent [37], cyanoacrylates [39], polydimethylsiloxane [35], ammonium polyphosphate [40], SiO 2 / polymethyl-hydro siloxane synthesized by sol-gel [41], Nano-SiO 2 within organic films [42].…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Lightweight Mortars by Nanopolymers to Improve Their Water-Repellency and Durability

et al. 2020

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The paper explores the possibility of covering the mortar with the lightweight aggregate by the nanopolymer silane and siloxane as surface hydrophobisation. The investigation involved the mortars with two types of hydrophobic agents diluted with water in a ratio of 1:4 and 1:8. Mortar wetting properties were determined by measuring the absorbability, water vapor diffusion, contact angle (CA) and surface free energy (SFE) of their structure. Surface micro-roughness and 2D topography were evaluated. Scanning electron microscopy (SEM) has shown the microstructure and distribution of pores in mortars. The reduction in absorbency after the first day of testing by 87% was shown. An improvement in frost resistance after 25 cycles by 97% and an 18-fold decrease in weight loss after the sulphate crystallization test were observed. The hydrophobic coating reduces the SFE of mortars and increases the CA. In the case of using silanes, a 9-fold increase CA was observed.

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Section: Introductionmentioning

confidence: 99%

Surface Modification of Lightweight Mortars by Nanopolymers to Improve Their Water-Repellency and Durability

et al. 2020

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“…One was the penetrative protective agent based on organic materials, with intention to block the surface pore structure; the other was the inorganic materials, such as mortar or cement paste, to isolate the matrix from erosion ions in outside environment. Silanes [16], ethyl silicate [17,18], and isobutyl-triethoxy-silane [19] were used as typical penetrative protective agents for the resistance of carbonation and erosion, and a silica-based hybrid nanocomposite was reported for surface treatment to reduce the water absorption and gas permeability [20]. One mechanism behind the enhanced impermeability was that the chemicals could go through the capillary and form an inorganic hydrophobic film along the capillary as a result of reacting with hydration products; the other was that these hydrates in the capillary structure would block the transportation of water and gas [21].…”

Section: Introductionmentioning

confidence: 99%

Effect of Nanosilica on Impermeability of Cement‐Fly Ash System

Liu

Zhang

Tong

et al. 2020

Advances in Civil Engineering

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Surface protection has been accepted as an effective way to improve the durability of concrete. In this study, nanosilica (NS) was used to improve the impermeability of cement-fly ash system and this kind of material was expected to be applied as surface protection material (SPM) for concrete. Binders composed of 70% cement and 30% fly ash (FA) were designed and nanosilica (NS, 0–4% of the binder) was added. Pore structure of the paste samples was evaluated by MIP and the fractal dimension of the pore structure was also discussed. Hydrates were investigated by XRD, SEM, and TG; the microstructure of hydrates was analyzed with SEM-EDS. The results showed that in the C-FA-NS system, NS accelerated the whole hydration of the cement-FA system. Cement hydration was accelerated by adding NS, and probably, the pozzolanic reaction of FA was slightly hastened because NS not only consumed calcium hydroxide by the pozzolanic reaction to induce the cement hydration but also acted as nucleation seed to induce the formation of C-S-H gel. NS obviously refined the pore structure, increased the complexity of the pore structure, and improved the microstructure, thereby significantly improving the impermeability of the cement-FA system. This kind of materials would be expected to be used as SPM; the interface performance between SPM and matrix, such as shrinkage and bond strength, and how to cast it onto the surface of matrix should be carefully considered.

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“…The hydrophobicity of cement-based materials is predominantly improved by surface hydrophobic modification and internal hydrophobic modification [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Generally, surface hydrophobic modification involves the surface treatment of cement-based materials, such as coating, dipping and spraying.…”

Section: Introductionmentioning

confidence: 99%

“…Super-hydrophobic concrete has been developed by spraying ethylene–vinyl acetate copolymer to improve its structural property [ 16 ]. A silica-based hybrid nanocomposite, SiO 2 /polymethylhydrosiloxane (SiO 2 /PMHS), has been used for the surface treatment of cement-based materials, which can reduce their water absorption and air permeability [ 17 ]. However, surface hydrophobic modification of cement-based materials exhibits limitations.…”

Section: Introductionmentioning

confidence: 99%

Hydrophobicity Improvement of Cement-Based Materials Incorporated with Ionic Paraffin Emulsions (IPEs)

et al. 2020

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Cement-based materials are non-uniform porous materials that are easily permeated by harmful substances, thereby deteriorating their structural durability. In this work, three ionic paraffin emulsions (IPEs) (i.e., anionic paraffin emulsion (APE), cationic paraffin emulsion (CPE), and non-ionic paraffin emulsion (NPE), respectively) were prepared. The effects of incorporation of IPEs into cement-based materials on hydrophobicity improvement were investigated by environmental scanning electron microscopy (ESEM), Fourier transform infrared (FTIR) spectroscopy, transmission and reflection polarizing microscope (TRPM) tests and correlation analyses, as well as by compressive strength, impermeability, and apparent contact angle tests. Finally, the optimal type and the recommended dose of IPEs were suggested. Results reveal that the impermeability pressure and apparent contact angle value of cement-based materials incorporated with IPEs are significantly higher than those of the control group. Thus, the hydrophobicity of cement-based materials is significantly improved. However, IPEs adversely affect the compressive strength of cement-based materials. The apparent contact angle mainly affects impermeability. These three IPEs impart hydrophobicity to cement-based materials. In addition, the optimal NPE dose can significantly improve the hydrophobicity of cement-based materials.

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Design of SiO 2 /PMHS hybrid nanocomposite for surface treatment of cement-based materials

Cited by 70 publications

References 44 publications

Surface Modification of Lightweight Mortars by Nanopolymers to Improve Their Water-Repellency and Durability

Surface Modification of Lightweight Mortars by Nanopolymers to Improve Their Water-Repellency and Durability

Effect of Nanosilica on Impermeability of Cement‐Fly Ash System

Hydrophobicity Improvement of Cement-Based Materials Incorporated with Ionic Paraffin Emulsions (IPEs)

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