Preparation and mechanical properties of asphalt mixtures reinforced by modified bamboo fibers
Introduction
Asphalt pavement is widely used in high-grade highways due to its comfortability for driving. However, asphalt pavement is prone to cracking due to its low tensile strength. Propagation of micro-cracks would reduce the service life of asphalt pavement [1], [2]. Incorporation of fibers into asphalt mixture is beneficial to the improvement of pavement strength and modulus. Steel fibers, glass fibers, basalt fibers, polymer fibers, and natural plant fibers have been investigated as reinforcements in asphalt pavements [1], [3], [4], [5].
Plant fibers have attracted much attention as asphalt mixture reinforcements. Research indicated that addition of cellulose fiber for hot-mix asphalt mixture (HMA) improved its penetration and softening point as well as the resistance to rutting of HMA [6]. The dynamic modulus and phase angle of asphalt mixture decreased due to the addition of cellulose fibers while the stiffness of fiber-modified asphalt mixtures could be reduced and the flexibility of mixtures was improved [7]. Aswathy et al. found that coconut shell charcoal could replace stone powder as a filler in stone mastic asphalt [8]. Oda et al. studied the application of natural fibers in stone matrix asphalt (SMA), and the results showed that the viscosity of asphalt mixed with natural fibers increased and the overflow of asphalt in the mixture was inhibited [9]. Aliha et al. concluded that the addition of plant fibers was beneficial to the improvement of low temperature performance of asphalt concrete [10]. Kar et al. determined that the optimal usage of sisal fiber in asphalt concrete was 0.3% for SMA mixture. And this mixture can be applied in flexible pavement [11]. The modification of plant fibers is usually carried out to improve their interfacial adhesion with asphalt matrix [12], [13]. The commonly used methods include physical treatment [14] and chemical modification [15]. Ghali et al. found that the mechanical properties and water resistance of the luffa fiber reinforced asphalt material were significantly improved after fiber treatment [16].
Green bamboo (Dendrocalamopsis oldhami Munro) is a fast-growing species and can be easily harvested for fibers extraction. BFs are potential reinforcements for asphalt mixture due to their intrinsic advantages such as low-cost, renewability, and high specific strength and stiffness [9], [17]. The properties of BFs-reinforced asphalt composites have been investigated [18], [19], [20]. However, the interfacial adhesion between BFs and asphalt matrices is poor due to the high hydrophilicity of BFs and the hydrophobicity of asphalt [21], [22]. This limits the reinforcing effects of BFs on asphalt mixture and application of BFs-asphalt composites in pavements.
Surface modification of BFs is an effective way to improve the interfacial adhesion between the fibers and asphalt. BF mainly consists of cellulose, hemicellulose, and lignin. The hydroxyl groups of BF cellulose can be grafted with a functional monomer or copolymer [23], thus a coupling agent is introduced between BFs and asphalt. In this study, a melamine–formaldehyde (MF) copolymer was synthesized and then used to modify BFs. The interaction between the MF copolymer and the BFs was characterized by FTIR, XPS, and NMR analyses. The mechanical properties of the BFs reinforced asphalt composites were evaluated. The interfacial adhesion between modified BFs and asphalt matrix was also studied.
Section snippets
Aggregates
Basalt aggregates with gradations of 3–5 mm, 5–10 mm, and 10–15 mm, were used as the coarse aggregates in asphalt mixture. Fine limestone sands were used as fine aggregates and ore powders as additive. All the aggregates and ore powders were purchased from Fujian Zhonghao Mining Co. Ltd. (Fujian, China). The properties of the coarse aggregates, fine aggregates, and ore powders were evaluated. The results are shown in Table 1, Table 2, Table 3.
Asphalt binder
The asphalt binder of #70 Grade A for pavement was
Surface chemistry of BFs
Melamine is a triazine nitrogen-containing heterocyclic organic compound. Under a neutral or slight alkaline condition, melamine could react with formaldehyde to form various methylol melamine copolymers. As shown in Fig. 4, during the treatment of BFs, excessive melamine would react with formaldehyde to form a melamine–formaldehyde (MF) copolymer with N-hydroxymethyl substitutes for further reaction with BFs. When the MF copolymer was sprayed onto the BFs surface, the hydroxyl groups of BFs
Conclusions
BFs were used as reinforcement in asphalt mixture. The specimens of asphalt mixtures were fabricated with optimum preparation parameters including BF length of 20 mm, BF loading of 0.2 wt% based on the total weight, and ratio of asphalt to aggregates (RAA) of 4.5%. The BFs were modified by melamine–formaldehyde (MF) copolymer to improve the interfacial adhesion between BFs and asphalt matrix. The mechanical properties of the BFs/asphalt mixtures were evaluated in terms of Marshall stability
CRediT authorship contribution statement
Demei Yu: Conceptualization, Methodology, Formal analysis, Writing - original draft. Anming Jia: Methodology, Formal analysis, Validation, Investigation, Resources. Chao Feng: Formal analysis. Wendi Liu: Methodology, Formal analysis, Validation, Investigation. Tengfei Fu: Writing - review & editing, Conceptualization, Supervision. Renhui Qiu: Writing - review & editing, Supervision, Project administration.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgement
The authors thank the financial support from the Fujian Provincial Department of Science and Technology, China (grant No. 2018H6004) and Fujian Agriculture and Forestry University, China (grant No. KFA17259A).
References (34)
Investigation of usability of basalt fibers in hot mix asphalt concrete
Constr. Build. Mater.
(2013)- et al.
Utilisation of natural fibre as modifier in bituminous mixes: a review
Constr. Build. Mater.
(2014) - et al.
Evaluating the fatigue properties of hot mix asphalt reinforced by recycled PET fibers using 4-point bending test
Constr. Build. Mater.
(2017) - et al.
The effects of fibers on the performance of bituminous mastics for road pavements
Compos. Part B: Eng.
(2016) - et al.
Investigation of the dynamic and fatigue properties of fiber-modified asphalt mixtures
Inter. J. Fatigue.
(2009) - et al.
Analysis of use of natural fibers and asphalt rubber binder in discontinuous asphalt mixtures
Constr. Build. Mater.
(2012) - et al.
The influence of natural and synthetic fibers on low temperature mixed mode I+II fracture behavior of warm mix asphalt
Eng. Fracture Mechanics.
(2017) - et al.
Effects of the atmospheric plasma treatments on surface and mechanical properties of flax fiber and adhesion between fiber–matrix for composite materials
Compos. Part B: Eng.
(2013) A review of Australian research into natural fiber cement composites
Cem. Concr. Compos.
(2005)- et al.
Mechanical properties of hemp fiber reinforced cement: Influence of the fiber/matrix interaction
J. Euro. Ceram. Soc.
(2008)
Experimental study of fibers in stabilizing and reinforcing asphalt binder
Fuel
Regulating tannic acid-crosslinked epoxidized soybean oil oligomers for strengthening and toughening bamboo fibers-reinforced poly(lactic acid) biocomposites
Compos. Sci. Technol.
Melamine polymerization in organic solutions and waterlogged archaeological wood studied by FTIR spectroscopy
J. Cult. Herit.
Evaluation of surface lignin on cellulose fibers with XPS
Appli Surface Sci.
Linearized approach for predicting thermal stresses in asphalt pavements due to environmental conditions
J. Mater. Civil Eng.
The effect of polypropylene fibers on asphalt performance
Build. Envir.
Assessment of suitability of coconut shell charcoal as a filler in stone mastic asphalt
Inter. J. Sci. Eng. Res.
Cited by (26)
Investigation on the rheological properties and modification mechanism of waste badminton shuttlecock modified asphalt binder
2024, Environmental Technology and InnovationRecent development and application of natural fiber in asphalt pavement
2024, Journal of Cleaner ProductionSurface modification of bagasse fibers based on polyphenol-induced self-supplied lignin for the creation of composite SBS-modified asphalt
2024, Industrial Crops and ProductsExperimental investigation on the preparation and surface treatment of biomass fibers for stone mastic asphalt mixtures modification
2023, Construction and Building MaterialsRecent developments on natural fiber concrete: A review of properties, sustainability, applications, barriers, and opportunities
2023, Developments in the Built EnvironmentThe use of fibres in asphalt mixtures: A state of the art review
2023, Construction and Building Materials