Superhydrophobic rice husk ash coating on concrete

Husni, H; Nazari, Mahsa; Yee, Hooi Min; Rohim, Rohamezan; Yusuff, Amer; Ariff, Mohd Azahar Mohd; Ahmad, Nor Naimah Rosyadah; Leo, C.P.; Junaidi, Mohd Usman Mohd

doi:10.1016/j.conbuildmat.2017.03.078

Cited by 84 publications

(29 citation statements)

References 21 publications

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“…However, these methods employ complicated processes, requiring specific equipment, rigorous preparation conditions, special substrates, and expensive/toxic fluoro silanes. In recent years, the fabrication of hydrophobic surfaces using waste materials and carbonaceous films has received significant attention [46][47][48][49][50][51]. Silica could be extracted from rice husk ash [46,47], oil palm fuel ash [12], and paper waste sludge ash [48,49] to fabricate various hydrophobic substrates.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Hydrophobic Coatings Using Sugarcane Bagasse Waste Ash as Silica Source

Natarajan¹,

Subramaniyam²,

Kumaravel

2019

Applied Sciences

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Eco-friendly hydrophobic coatings were fabricated on tiles via the drop-casting process. Sugarcane bagasse waste ash (SBA) was used as a silica source and dimethyldiethoxysilane (DMDEOS) was used as a surface functionalizing agent. The elemental composition of SBA was measured using X-ray fluorescence (XRF) and energy-dispersive spectroscopy (EDS) techniques. The surface morphology of SBA was analyzed through the field-emission scanning electron microscopy (FESEM) technique. The surface wettability of SBA coated tiles was evaluated by determining the static water contact angle (WCA). XRF studies showed that the impurities were removed, and the silica content was enriched by the acid treatment. SBA coated tiles showed good hydrophobicity with a WCA of 135°. The high hydrophobicity of the coated tiles may be attributed to the increase of surface roughness by SBA. Moreover, the SBA coating was successfully tested on various substrates such as tiles, brick, glass, and cotton cloth. SBA coated glass substrate was more durable compared to other substrates at normal room temperature.

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Section: Introductionmentioning

confidence: 99%

Fabrication of Hydrophobic Coatings Using Sugarcane Bagasse Waste Ash as Silica Source

Natarajan¹,

Subramaniyam²,

Kumaravel

2019

Applied Sciences

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“…Another example of environment-friendly products is the ashes of industrial and agricultural residues. Husni et al [37], Junaidi et al [15], Junaidi et al [23] used rice husk ashes, an abundantly available by-product, to create superficial microroughness to achieve superhydrophobicity. These ashes contain about 97% silica and may replace the commonly employed commercial nanoparticles in the manufacturing of hydrophobic coatings.…”

Section: Superhydrophobic Coatings Applied To Cementitious Materialsmentioning

confidence: 99%

Recent Advances and New Discussions on Superhydrophobic Coatings and Admixtures Applied to Cementitious Materials

Carneiro¹,

Houmard²,

Ludvig³

2020

TOBCTJ

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Increasing the durability of buildings is one of the biggest challenges of the construction industry of the 21st century. The problems concerning durability are usually related to the presence of humidity or to water infiltration in the porous cementitious materials used in buildings. Advances in biomimetics have allowed the development of superhydrophobic surfaces and materials, with contact angles greater than 150°, which are able to repel water and aqueous products. In this context, this work summarizes the recent advances on superhydrophobic coatings and admixtures applied to cementitious materials. Recommendations for the future improvement of such products are made. The synthesis of superhydrophobic coatings generally includes the deposition of a low surface energy material (LSEM), especially fluoroalkylsilanes, on a microroughened surface, which, in cementitious materials, is usually achieved with the help of nanoparticles or micrometric molds. In this sense, variables as the spraying time duration, and the nanoparticles concentration, surface area and average particle size were identified as directly influencing the surface superhydrophobicity. Functionalized nanoparticles can also be introduced in cement matrix during the paste mixing in order to obtain a longer lasting waterproofing effect. In this case, hybrid nanosilica may react with Ca(OH)2 through pozzolanic reaction. The C-S-H formed may incorporate the organic group of hybrid nanosilica, and might present superhydrophobicity as well, modifying the composite’s microstructure. Besides, the cost of fabricating hydrophobic materials is decisive for their market entry. Hence, the partial or total replacement of fluoroalkylsilanes with less expensive LSEMs seems promising and needs to be further explored.

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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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Superhydrophobic rice husk ash coating on concrete

Cited by 84 publications

References 21 publications

Fabrication of Hydrophobic Coatings Using Sugarcane Bagasse Waste Ash as Silica Source

Fabrication of Hydrophobic Coatings Using Sugarcane Bagasse Waste Ash as Silica Source

Recent Advances and New Discussions on Superhydrophobic Coatings and Admixtures Applied to Cementitious Materials

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

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