scholarly journals Influence of Hydrophobic Coating on Freeze-Thaw Cycle Resistance of Cement Mortar

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Zijian Song ◽  
Zhongyuan Lu ◽  
Zhenyu Lai
Keyword(s):  
Surface Energy ◽  
Chemical Modification ◽  
Cement Mortar ◽  
Mass Loss Rate ◽  
Water Contact ◽  
Freeze Thaw ◽  
Hydrophobic Coating ◽  
Low Surface Energy ◽  
Thaw Cycle ◽  
Cement Based Materials

Due to the porous characteristics of cement-based materials, they are often corroded by salt solutions, which results in decreased durability, especially against damage under freeze-thaw cycles (FTCs). Improving surface properties is an effective way to improve the durability of these materials. In this study, a hydrophobic coating was applied to the surface of cement mortar by chemical modification of low surface energy materials. Fourier transform infrared spectroscopy (FT-IR) showed that low surface energy substances are linked to hydration products through chemical bonds. A water contact angle test indicates that the surface of cement mortar changed from hydrophilic (θ = 14°) to hydrophobic (θ = 140°) after chemical modification. The cumulative water uptake of hydrophobic samples decreased by 90%. Meanwhile, the wear resistance of the hydrophobic coatings was excellent. Compared with the baseline sample, mass loss rate, flexural strength, and compressive strength of hydrophobic coating samples increased several-fold in the FTC test. Microstructural changes of the mortar were characterized by scanning electron microscopy. The results show that a hydrophobic coating can significantly improve the freeze-thaw resistance of cement-based materials. The formation of a hydrophobic layer on the surface of cement-based materials can improve their durability. The research results not only have applications in civil engineering but will also have great impact in the restoration of historic structures.

Effect of Mica Content in Stone Powder of Manufactured Sand on Performance of Cement Mortar

2014 ◽  
Vol 1044-1045 ◽  
pp. 624-628
Author(s):  
Jie Quan Xing ◽  
Shu Lin Zhan ◽  
Xin Yu Li
Keyword(s):  
Compressive Strength ◽  
Loss Rate ◽  
Cement Mortar ◽  
Mass Loss Rate ◽  
Strength Loss ◽  
Freezing Resistance ◽  
River Sand ◽  
Manufactured Sand ◽  
Freeze Thaw ◽  
Different Content

This paper studies the influence on compressive strength, freezing resistance and microstructure of cement mortar with different content of mica in stone powder, in the tests, manufactured sand with high content of mica and natural river sand were mixed with different proportion, and the content of stone powder was the same in mixed sand. Experiment results indicate that, with the increasing of mica content in stone powder, 28d and 60d compressive strength of cement mortar decreases obvious, mass loss rate and strength loss rate with 50 freeze-thaw cycles increase a little. Microstructure of cement mortar with higher content of mica is not compactly by SEM, the internal defects of cement hardened pastes could be increased because of the flake mica which surface is smooth, and it will cause the spread of micro crack.

scholarly journals Recent Advances in Hydrophobic and Icephobic Surface Treatments of Concrete

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 449 ◽  
Author(s):  
Rosa Di Mundo ◽  
Claudia Labianca ◽  
Giuseppe Carbone ◽  
Michele Notarnicola
Keyword(s):  
Hydrophobic Surface ◽  
Chloride Penetration ◽  
Surface Treatments ◽  
Water Contact ◽  
Freeze Thaw ◽  
Water Ingress ◽  
Superhydrophobic Coatings ◽  
Cement Based Materials ◽  
Pore Blockage ◽  
Huge Variety

In this review, we present a survey on hydrophobic surface treatments of concrete, important protection tools against deterioration and corrosion phenomena. In the frame of a standardized distinction in coatings, pore blockage, and impregnation methods, we highlight the huge variety of compounds and formulations utilized, and the different performances reached in terms of water contact angle, water absorption, chloride penetration, and, rarely reported, anti-icing/icephobic action. Our view covers the spectrum of the surface treatments, but also makes a comparison with hydrophobic bulk modifications of concrete, procedures often utilized as well; further, novel proposals of more sustainable routes are presented. We note that coating and impregnation, preferably when based on polyurethane and silane/siloxane, respectively, appear more effective against water ingress. The achieved wetting character is hydrophobic or, at most, overhydrophobic. Superhydrophobic coatings for concrete have been obtained by embedding nano-powders in hydrophobic emulsions, allowing to add a nanotexture to the preexisting complex roughness of the material. Concrete treated with this type of coating has also recently shown a pronounced icephobic character, a parameter that goes beyond the freeze–thaw characterization usually conducted on cement-based materials.

The Polymerization and Performance of Fluorinated Acrylic Copolymer with Low Surface Energy

2011 ◽  
Vol 687 ◽  
pp. 562-566
Author(s):  
Yan Zhang ◽  
Zhan Ping Zhang ◽  
Yu Hong Qi ◽  
Xin Rui Gao
Keyword(s):  
Surface Energy ◽  
Monomer Conversion ◽  
Ethyl Acrylate ◽  
Carbon Chain ◽  
Solid Content ◽  
Coating Materials ◽  
Water Contact ◽  
Acrylic Copolymer ◽  
Low Surface Energy ◽  
And Performance

Fluoro-polymer is of great importance as coating materials because of their excellent resistance to high temperature, chemicals and organic solvents. In the interest of researching low surface energy coating, a kind of copolymer was prepared by solution polymerization method, using methyl methacrylate, butyl acrylate, 2-hydroxyethyl acrylate and perfluoroalkyl ethyl acrylate whose length of fluorinated carbon chain was from 6 to12. Solid content, monomer conversion rate and viscosity of the copolymer were measured. Parallel experiments were separately carried out with different contents of initiator and fluorinated monomer. The results showed that the water contact angle of the film becomes bigger with the increase of the content of fluorinated monomer, with the biggest value in 108° when the content of fluorinated monomer content is 30 wt%, but only changing little after content of fluorinated monomer reaches up 15 wt%. The results indicated that the copolymer can offer the best property combination when the contents of fluorinated monomer and initiator were 15 wt% and 1.8 wt%.

Three-level hierarchical superhydrophobic Cu–Zn coating on a steel substrate without chemical modification for self-cleaning property

2017 ◽  
Vol 41 (13) ◽  
pp. 5436-5444 ◽  
Author(s):  
Hao Li ◽  
Sirong Yu
Keyword(s):  
Surface Energy ◽  
Chemical Modification ◽  
Steel Surface ◽  
Steel Substrate ◽  
Chemically Modified ◽  
Low Surface Energy ◽  
Energy Material ◽  
One Step ◽  
Self Cleaning

A superhydrophobic Cu–Zn coating was fabricated on a steel surface by facile one-step electrodeposition, without being chemically modified by a low surface energy material.

Study on Fluorocarbon Antifouling Coatings with Low Surface Energy

2011 ◽  
Vol 689 ◽  
pp. 445-449
Author(s):  
Chun Hong Qiu ◽  
Yu Hong Qi ◽  
Zhan Ping Zhang ◽  
Hui Gao
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Dynamic Testing ◽  
Marine Diatom ◽  
Silicone Resin ◽  
Water Contact ◽  
Antifouling Coating ◽  
Low Surface Energy ◽  
Antifouling Coatings

To develop non-toxic marine antifouling coating, a series of antifouling coatings were prepared based on fluorocarbon copolymer. Based on the measurement of roughness and water contact angle, the attachment test of marine diatom and bacteria before and after dynamic testing in seawater, it has been investigated that the influence of three functional fillings and silicone resin on the performance of the antifouling coatings with low surface energy. The erosion rate of the coatings was measured by the samples rotated 72h at the 12 knots of simulating sailing speed. The results showed that the roughness of coatings changes from 0.2um to 3um, it does influenced slightly by the rotating test. Water contact angle of all coatings is about 100° before rotating test. It decreases to about 70° after the rotating test in seawater. Due to the increase of surface energy of the coatings, both the amount of diatom and bacteria on samples increases after rotating test in seawater.

scholarly journals Durability Of Advanced Cement-Based Materials Used As Repairs For Deteriorated Concrete

2021 ◽  
Author(s):  
Keikhosrow Tahmureszadeh
Keyword(s):  
Bond Strength ◽  
High Performance Concrete ◽  
Construction Material ◽  
Advanced Technology ◽  
Repair System ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Cement Based Materials ◽  
Strength And Durability ◽  
Durability Performance

With advanced technology, the production of strong construction material becomes more feasible. However, use of such materials as repairs on top of existing concrete is challenging, since repair system relies not only on the quality of repair but also on the interaction and compatibility of such material with the substrate. Studies regarding the durability of bond strength are limited. Therefore, the objective of this research is to compare the bond strength and durability performance of advanced cement-based materials including ultra-high performance concrete (UHPC), engineered cementitious composite with slag (ECC-Slag), specialized repair material with self-consolidating properties (SCC), and normal concrete (NC) under two common deterioration modes in Canada (freeze-thaw cycles with de-icing salt, and volumetric expansion of the substrate). The freeze-thaw cycle results show higher bond strength and durability performance for UHPC and NC, respectively. Under expanding deterioration, NC started with higher bond strength and UHPC revealed the best durability performance.

Development of non-fluorine superhydrophobic textiles using polypropylene resins

2019 ◽  
Vol 89 (19-20) ◽  
pp. 4015-4027 ◽  
Author(s):  
Jung Yoon Kim ◽  
Changsang Yun ◽  
Chung Hee Park
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Vapor Permeability ◽  
Mixing Ratio ◽  
Water Contact ◽  
Environmental Friendliness ◽  
Drying Temperature ◽  
Low Surface Energy ◽  
Develop Environment

This study aims to develop environment-friendly superhydrophobic textiles forming nanoparticles of polypropylene that have intrinsically low surface energy, and thus achieving the requirements for superhydrophobicity, such as hierarchical roughness and low surface energy at once. This work mainly studies the influences of tacticity (isotactic, atactic), concentration (10, 20, 30 and 40 mg/ml), drying temperature (30℃ and 70℃) and the mixing ratio of the solvent/non-solvent (9:1, 8:2, 7:3 and 6:4) on the coating morphology and wettability. In the case of isotactic polypropylene, the optimal condition showing the water contact angle of 173° and the water shedding angle of 4° was at 70℃ drying temperature, 30 mg/ml concentration and 6:4 solvent/non-solvent mixing ratio. Amorphous polypropylene showed the water contact angle of 163° and the water shedding angle of 9° at the condition of 30℃ drying temperature, 40 mg/ml concentration and 8:2 solvent/non-solvent mixing ratio. It was revealed that superhydrophobicity by amorphous polypropylene was exhibited at lower drying temperature and lower mixing ratio for the non-solvent. This is attributed to the different evaporation temperature or speed of the solvent/non-solvent mixing according to the tacticity of polypropylene. This study demonstrated that environmental-friendliness was improved in that superhydrophobic textiles were developed without fluorine compounds, maintaining vapor permeability. This study also developed a finishing method using amorphous polypropylene under a mild condition in terms of drying temperature and solvent toxicity, which is expected to be applicable not only to polyester but also to various fabrics.

scholarly journals Preparation of UV-Curable Low Surface Energy Polyurethane Acrylate/Fluorinated Siloxane Resin Hybrid Coating with Enhanced Surface and Abrasion Resistance Properties

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1388
Author(s):  
Jianping Zhou ◽  
Chunfang Zhu ◽  
Hongbo Liang ◽  
Zhengyue Wang ◽  
Hailong Wang
Keyword(s):  
Surface Energy ◽  
Abrasion Resistance ◽  
Hybrid Film ◽  
Annealing Treatment ◽  
Annealed Film ◽  
Surface Hydrophobicity ◽  
Water Contact ◽  
Uv Curable ◽  
Polyurethane Acrylate ◽  
Low Surface Energy

Low surface energy coatings have gained considerable attention due to their superior surface hydrophobic properties. However, their abrasion resistance and sustainability of surface hydrophobicity are still not very satisfactory and need to be improved. In this work, a series of utraviolet (UV)-curable fluorosiloxane copolymers were synthesized and used as reactive additives to prepare polyurethane acrylate coatings with low surface energy. The effect of the addition of the fluorinated graft copolymers on the mechanical durability and surface hydrophobicity of the UV-cured hybrid films during the friction-annealing treatment cycles was investigated. The results show that introducing fluorosiloxane additives can greatly enhance surface hydrophobicity of the hybrid film. With addition of 2 wt.% fluorosiloxane copolymers, the water contact angle (WCA) value of the hybrid film was almost tripled compared to that of the pristine PU film, increasing from 58° to 144°. The hybrid film also showed enhanced abrasion resistance and could withstand up to about 60 times of friction under a pressure of 20 kPa. The microstructure formed in the annealed film was found to contribute much to achieve better surface hydrophobicity. The polyurethane acrylate/fluorinated siloxane resin hybrid film prepared in this study exhibits excellent potential for applications in the low surface energy field.

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