Treatment of Natural Fiber for Application in Concrete Pavement

Table 4

Main advantage and limitation of each treatment technique.

		Advantage		Limitation	References
Surface treatment techniques	Physical method	Plasma method
			(i) It eliminates softly unwanted parts from a surface layer or develops a novel functional cluster.	(i) Being degraded and modifying the surface of fiber arise due to the etching mechanism that creates pits on the external fiber zone.	[83, 84]
			(ii) It successfully modifies the surface properties and eliminates the operation of biologically harmful elements.
			(iii) No change occurs in the bulk properties of treated fibers.
	Chemical treatments	Alkali treatment	(i) It successfully removed impurities (hemicelluloses and lignin).	(i) A large amount of water is needed for washing and also long pretreatment resident time.	[85, 86]
			(ii) It can alter the smooth surface to be rough fiber surfaces by preparing well mechanical meshing and more muscular interfacial strength of the fiber-matrix.	(ii) Its mechanical property depends on the percentage of alkali solution treatment, duration, and temperature.
		Silane treatment	(i) It enhances hardiness and lowers water absorption of the fibers subsequent in hydrophobic composites.	(i) It is a coupling agent that depends on the treatment of the alkali solution.	[87, 88]
			(ii)It improves the thermal stability of the composites.
		Acetylation treatment	(i) It improves crystallinity, reduces water adsorption capacity, and increases the fiber-matrix adhesion properties.	(i) It enlarges acetylation, reducing mechanical properties due to the degradation of cellulose and cracking of fibers.	[89, 90]
		Maleic anhydride treatment	(i) It increases fiber-matrix adhesion and thermal stability and also reduces water.	(i) It is highly motivated by compactness, temperature, and fiber loading.	[91, 92]
			(ii) It improves the property of composite material.
		Benzoylation treatment	(i) It decreases the hydrophilicity, improves the fiber-matrix bond, and also enhances the strength of the composite.	(i) It is a coupling agent that depends on the treatment of the alkali solution.	[87, 93]
	Biological treatment	Retting treatment	(i) It is eco-friendly with surrounding and has lower energy consumption during processing excluding or diluters.	(i) Low scalability is limited to the laboratory.	[94, 95]
			(ii) It improves fiber surface spotlessness and separated fiber bundles.	(ii) It partly eradicates pectic and hemicellulose constituents in cellulose fiber.