scholarly journals Surface Modification of Rusted Rebar and Enhanced Passivation/Anticorrosion Performance in Simulated Concrete Pore Solutions with Different Alkalinity

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1050 ◽  
Author(s):  
Dan Song ◽  
Falin Yang ◽  
Mingzhi Guo ◽  
Sujing Zhao ◽  
Jun Hao ◽  
...  
Keyword(s):  
Surface Modification ◽  
Reinforced Concrete ◽  
Chloride Ion ◽  
Metallic Surface ◽  
Great Promise ◽  
Electrochemical Tests ◽  
Direct Exposure ◽  
Wire Brushing ◽  
Anticorrosion Performance ◽  
Surface Modified

Naturally exposed rusted rebar has been widely used for the production of reinforced concrete. However, rusted rebar is prone to corrosion under chloride ion (Cl−) contamination and/or at a low alkalinity of concrete. This study employed two surface modification methods, sand blasting and wire brushing, to augment the corrosion resistance of naturally exposed rusted rebar. Electrochemical tests revealed that the surface-modified rebar displayed a significant improvement of passivation in the concrete alkaline environment and anticorrosion performance in both the Cl− free and Cl−-containing simulated concrete pore solutions of different alkalinity. The enhanced performance was mainly due to the elimination of the rust layer and the direct exposure of the fresh metallic surface to the alkaline medium. Moreover, the effect of surface nanograins on the intensified passive film led to the best passivation performance of the wire-brushed rebar. The overall findings demonstrate that the two developed methods were conducive to the passivation and anticorrosion performance of the rusted rebar and thereby hold great promise for improving the service life of the reinforced concrete structures.

scholarly journals Influence of the surface modification by sanding of carbon textile reinforcements on the bond and load-bearing behavior of textile reinforced concrete

2019 ◽  
Vol 289 ◽  
pp. 04006
Author(s):  
Cynthia Morales Cruz ◽  
Michael Raupach
Keyword(s):  
Surface Modification ◽  
Reinforced Concrete ◽  
Tensile Tests ◽  
Measuring System ◽  
Uniaxial Tensile ◽  
Testing Time ◽  
Textile Reinforced Concrete ◽  
Load Bearing ◽  
Surface Modified ◽  
Bearing Behavior

In the context of the application of carbon Textile Reinforced Concrete (TRC) layers for the durable repair of building surfaces, uniaxial tensile tests on rectangular TRC samples were carried out to compare the bond and load-bearing behavior of an epoxy-impregnated carbon textile and its surface modified version. The aim of the surface modification, consisting of a subsequent coating with epoxy resin and sanding with quartz sand, is the improvement of the composite material regarding crack width reduction and an increase of the load-bearing capacity. A total of 15 series were examined and the parameters: reinforcement type, orientation and ratio were varied. In addition, long-term load tests were conducted. An optical 3D-video measuring system in combination with a DIC-software was used, which allowed the analysis of the process of crack formation during the entire testing time. With the surface modified reinforcement the formation of approx. 1.5 times the number of cracks with averagely 33 % smaller crack widths and up to 50 % smaller crack spacings were observed, regardless of the ratio of reinforcement. The residual behaviour of the series subjected to a permanent load of 1500 MPa over 1000 h showed no reduction of the tensile stress compared to short-term tests.

scholarly journals Facile Preparation of Efficient WO3Photocatalysts Based on Surface Modification

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Min Liu ◽  
Hongmei Li ◽  
Yangsu Zeng
Keyword(s):  
Photocatalytic Activity ◽  
Surface Modification ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Impregnation Method ◽  
Light Spectra ◽  
Simple Strategy ◽  
Visible Light Active ◽  
Efficient Charge ◽  
Surface Modified

Tungsten trioxide (WO3) was surface modified with Cu(II) nanoclusters and titanium dioxide (TiO2) nanopowders by using a simple impregnation method followed by a physical combining method. The obtained nanocomposites were studied by scanning electron microscope, X-ray photoelectron spectroscopy spectra, UV-visible light spectra, and photoluminescence, respectively. Although the photocatalytic activity of WO3was negligible under visible light irradiation, the visible light photocatalytic activity of WO3was drastically enhanced by surface modification of Cu(II) nanoclusters and TiO2nanopowders. The enhanced photocatalytic activity is due to the efficient charge separation by TiO2and Cu(II) nanoclusters functioning as cocatalysts on the surface. Thus, this simple strategy provides a facile route to prepare efficient visible-light-active photocatalysts for practical application.

A Novel Approach for Metal Surface Modification

2007 ◽  
Vol 280-283 ◽  
pp. 1805-1806
Author(s):  
Zhi Jun Cao ◽  
Jia Chen Liu ◽  
Li Bin Liu ◽  
Hao Ye ◽  
Yan Qiu Wei
Keyword(s):  
Surface Modification ◽  
Wear Rate ◽  
Charge State ◽  
Metal Surface ◽  
Surface Hardness ◽  
Metallic Surface ◽  
New Approach ◽  
Novel Approach ◽  
Complex Shapes ◽  
Enhanced Surface

A new approach was developed for surface modification of metallic surface. By treating nano-zirconia particles and metal surface in different charge state, nano-zirconia particles can be dispersedly inlaid in metal surface owing to electrostatic and nanometer effects. By using this method, metal components of complex shapes, especially those having inside surfaces, might be easily improved, i.e., enhanced surface hardness and wear rate.

scholarly journals Enhancement of the Congo Red Adsorption Capacity of Biochars by Surface Modification with MgCl2 Pretreatment

2020 ◽  
Vol 42 (10) ◽  
pp. 472-481
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Pine Sawdust ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Surface Modified

Objectives : The physicochemical characteristics of Mg-biochar composites derived from kelp and pine after pretreatment with MgCl2 were analyzed, and their adsorption capacities for an anionic dye, Congo red (CR), were evaluated.Methods : After pretreating 60 g of kelp and pine sawdust in 1 L of 0.1 M MgCl2･6H2O, the raw materials were pyrolyzed at 500℃ to produce Mg-biochar composites (kelp based KB-Mg and pine based PB-Mg). The fundamental physicochemical characteristics of the Mg-biochar composites were examined, and their adsorption capacities for CR were investigated using different initial pH values, adsorption kinetic models, and adsorption isotherm models.Results and discussion : The Mg-biochar composites showed the development of uniform deposits of Mg minerals primarily as MgO crystal on the surface by the surface modification with MgCl2. When the pristine biochars were surface-modified with MgCl2, their adsorption capacities for CR were significantly increased over the entire pH range tested. The CR adsorption process by all biochars was best described with the pseudo-first order kinetics model, and the adsorption isotherm characteristics were better described with the Langmuir isotherm model for all biochars. The Langmuir maximum adsorption capacities for KB-Mg and PB-Mg were 423.0 mg/g and 394.7 mg/g, respectively. It is suggested that the main mechanism for CR adsorption on the Mg-biochars is electrostatic attraction between CR and the biochars.Conclusions : The results showed that surface modification with MgCl2 could greatly enhance the CR adsorption capacity of biochars, and the results demonstrated the great potential of KB-Mg and PB-Mg for CR removal.

Surface modification of ferrite nanoparticles with dicarboxylic acids for the synthesis of 5-hydroxymethylfurfural: a novel and green protocol

RSC Advances ◽  
2016 ◽  
Vol 6 (80) ◽  
pp. 76795-76801 ◽  
Author(s):  
Melad Shaikh ◽  
Mahendra Sahu ◽  
Kiran Kumar Atyam ◽  
Kalluri V. S. Ranganath
Keyword(s):  
Surface Modification ◽  
Dicarboxylic Acids ◽  
Ferrite Nanoparticles ◽  
Solvent Free ◽  
Green Protocol ◽  
Flexible Ligand ◽  
Solvent Free Conditions ◽  
Surface Modified

5-Hydroxymethylfurfural (5-HMF) has been synthesized under solvent free conditions using surface modified ferrite nanoparticles. The flexible ligand modified ferrites showed higher activity than rigid modified ferrites.

A comparative study on mechanical properties of surface modified polypropylene (PP) fabric reinforced concrete composites

2017 ◽  
Vol 157 ◽  
pp. 372-381 ◽  
Author(s):  
Guyu Feng ◽  
Xinyue Wang ◽  
Diantang Zhang ◽  
Haijian Cao ◽  
Kun Qian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Comparative Study ◽  
Surface Modified

Insights on the impact of photophysical processes and defect states evolution on the emission properties of surface-modified ZnO nanoplates for application in photocatalysis and hybrid LEDs

2021 ◽  
Author(s):  
Dhritiman Banerjee ◽  
Payal Banerjee ◽  
Asit Kumar Kar
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Surface Modification ◽  
Defect State ◽  
Defect States ◽  
Emission Properties ◽  
Photophysical Processes ◽  
State Densities ◽  
Surface Modified ◽  
The Impact

The effects of surface modification on the defect state densities, optical properties, photocatalytic and quantum efficiencies of zinc oxide (ZnO) nanoplates have been studied in this work. Here, the aim...

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