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Article

Development of Structural Type Mortars Reinforced with Coconut (Cocos Nucifera) Fiber: Chemical, Thermal, and Mechanical Behavior

by
Mónica-Johanna Monsalve-Arias
1,*,
Oscar-Fabián Higuera-Cobos
2 and
Cristian-Antonio Pedraza-Yepes
2
1
Research Group AFIS, Mechanical and Mechatronic Engineering Department, Universidad Nacional de Colombia, Bogotá 111321, Colombia
2
Research Group CONFORMAT, Mechanical Engineering Program, Faculty of Engineering, Universidad del Atlántico, Puerto Colombia 081007, Colombia
*
Author to whom correspondence should be addressed.
J. Compos. Sci. 2025, 9(6), 300; https://doi.org/10.3390/jcs9060300
Submission received: 6 February 2025 / Revised: 24 April 2025 / Accepted: 25 April 2025 / Published: 12 June 2025
(This article belongs to the Special Issue Advancements in Sustainable Cement-Based Composites: Innovations in Performance, Durability, and Environmental Impact)
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Versions Notes

Abstract

In this research, the effect of the addition of coconut fibers coated with hydrophobic substances as reinforcement material in mortars was evaluated. Fibers of different sizes (1, 2, and 5 cm) were pretreated with linseed oil and paraffin wax, in order to obtain a mortar/fiber ratio of 0.5% and 1% by weight. The chemical resistance of the fibers were evaluated before and after being exposed to a concentrated solution of Ca(OH)2 in order to simulate the alkaline environment of the cement. The physicochemical characterization of the fibers was conducted by DTG (derivative thermogravimetry), TGA (thermogravimetric analysis), and FTIR (Fourier transform infrared spectrometry). The mechanical strength of the fiber-reinforced mortars was evaluated by compression and flexural tests. The effect of fiber degradation on mechanical behavior was evaluated between 28 days of processing. The results showed that the highest compressive and flexural strength were obtained with the composites reinforced with coconut fiber of 0.5% by weight, length of 1 cm, and paraffin wax as the impregnation substance.

1. Introduction

The disposal of agricultural residues is an environmental problem in many countries. Incorporating these residues into cementitious products is a practice that has been commonly used to solve these environmental problems. One of the most commonly used agricultural waste by-products are natural fibers including coconut, banana, sugarcane, jute, sisal, corn, and other fibers. The purpose of incorporating these fibers into the cementitious material is to improve the ductility, toughness, flexibility, and fracture resistance of the resulting material, among other benefits [1,2]. In addition, they are readily available, economical, low density, biodegradable, non-toxic, energy efficient, and environmentally friendly [1,3]. Coconut fiber (CF), extracted from discarded coconut shells, has a unique orientation of cellulose and hemicellulose, and this, combined with a lower concentration of these components compared with other plant fibers, reduces water absorption and minimizes bulk disruption of the cementitious matrix [4]. However, assessing the durability of these fibers is important, as natural materials tend to be biodegradable. For example, natural fibers with a high cellulose content (e.g., bamboo, kraft pulp, and cotton wool) tend to exhibit poor durability in highly alkaline environments. In the case of conventional concrete, which has an alkaline matrix with an initial pH typically around 12 to 14, the use of such fibers can be problematic. Compared with other natural fibers, coconut fiber has a low decomposition rate, which is explained by its high lignin content. However, despite its higher lignin content and lower cellulose content, some research has shown that coconut fiber is sensitive to alkalis and may also have some sensitivity to drying shrinkage or volumetric changes due to alternating wetting and drying [5]. For this reason, in recent years, efforts have been made to improve the quality of this type of composite material. The alkaline environment generated by the calcium hydroxide Ca(OH)2 and the presence of calcium ions, which react with the cellulose breaking the polymeric chains, causes a significant reduction in the strength of the composite material. Additionally, the volumetric changes of the fibers on the matrix and the predisposition to microorganism attack in humid environments must also be taken into account [6,7]. To reduce deterioration and increase the durability of cement mortars reinforced with vegetable fibers, it is necessary to modify the composition of the matrix in order to limit the effect of alkaline compounds that cause cellulose to reduce its reinforcing capacity. The second option is to change the surface physicochemical characteristics of the fibers by applying hydrophobic substances, in order to reduce the amount of water absorbed by the fiber, stabilizing the cement matrix [8]. In this work, mortars reinforced with coconut fibers coated with paraffin wax and linseed oil were mechanically evaluated, and the fiber size and quantity were analyzed.

2. Materials and Methods

2.1. Fabrication of the Mortar

The mortar under study was designed using the methodology proposed by Sánchez [9], which made it possible to define the respective proportions of cement, water, and fine aggregate, obtaining a mortar with a plastic consistency of 110%. The quantities used in the mixture were as follows: Argos Portland type I 14.81 kg; coir fiber (0.5 wt.%) 0.074 kg; coir fiber (1 wt.%) 0.1481 kg; water 10.96 kg; sand 56.88 kg and water/cement (A/C) ratio of 0.74. Table 1 shows the design of the experiments applied in this study. As response variables, the effect of the hydrophobic substance on the fibers, fiber length, and fiber ratio on the compressive and flexural strength was evaluated.

2.2. Preparation and Conditioning of the Fibers

Figure 1 summarizes the methodology for the preparation and conditioning of the fibers. Paraffin wax and linseed oil were used as protective hydrophobic substances, since they do not deteriorate the mortar and are economical.

2.3. Physicochemical Characterization of Fibers

Archimedes’ principle was used to determine the density (ρ) of the coconut fiber, as shown in Equation (1).
ρ = Fiber   weight ∆ V
where ΔV is the volume of liquid displaced.
The chemical resistance of the fibers was evaluated by weight loss after contact with an alkaline medium (Ca(OH)2) for 7 to 28 days according to Equation (2) [10].
P c r = 100 ∗ w 1 − w 2 w 1
where W1 is the initial fiber weight (0.2 g) and W2 is the final dry fiber weight after contact with the alkaline medium.
The characterization of the coated fibers was conducted by using the following techniques: (1) Fourier transform infrared spectroscopy (FTIR) in the range of 400–4000 cm−1, (2) thermogravimetric analysis (TGA/DTG) at a constant heating rate of 10 °C/min from 25 °C and 750 °C, and (3) stereomicroscopy at a magnification of 160×.

2.4. Mechanical Characterization

The mechanical behavior of the coconut fiber-reinforced mortars was evaluated by means of compression tests according to NTC 673 [10] using cylindrical specimens of 5.08 cm × 10.16 cm [11], and bending tests according to INV.E-324-07 [12] using rectangular specimens with dimensions of 4 × 4 × 16 cm at a spindle speed of 10 mm/min in a YUEKE universal machine. The specimens were manufactured in duplicate and tested at 7, 21, and 28 days.

3. Results and Discussion

3.1. Physicochemical Characterization of Fibers

3.1.1. Chemical Resistance

The main problem with the use of natural fibers in cementitious matrices is fundamentally associated with their durability, since the alkalinity of the matrix and the instability of the fiber cause a loss of strength of the composite material in the long-term. This is mainly due to the fact that cement-based compounds are characterized by being alkaline, that is, by having a high pH. Some authors have commented that the alkalinity of the water present in the pores of the matrix deteriorates the natural fiber to such a high degree that it even reaches the point of completely nullifying its action as a reinforcement material [10]. The deterioration process of natural fibers takes place when the composite is subjected to dry–wet cycles, mainly due to the environmental conditions to which they are exposed such as variations in relative humidity and natural aging in outdoor environments [13].
The first dry cycle in a natural fiber-reinforced matrix occurs when the cross-section of the fibers decreases as a result of water loss. This causes a lack of adhesion between the fiber and matrix, and it is here that empty spaces or gaps begin to appear in the interface [10]. In the first wet cycle, cement hydration products such as calcium hydroxide dissolve in the water, forming a solution that is absorbed by the fibers. During the second dry cycle, the water in the compound and the water contained in the fiber evaporate, respectively, so the solution moves toward the fibers, causing calcium hydroxide to be deposited on the surface and the lumen or inner part of the fiber, causing mineralization of the fibers. These cycles are repeated continuously, bombarding the fibers with calcium hydroxide, which causes them to densify with highly alkaline products, and consequently decreases their mechanical strength. In this way, when the fiber is immersed in an alkaline solution, the hydroxyl ions are incorporated into the cellulose, forming an isosacchagrinic acid, while when the cellulose is dried, it returns to its original state; however, calcium ions (Ca2+) bind to the ends of the acidic compound and break the cellulose chains when the fibers dry out [10,13]. Figure 2 (paraffin-protected) and Figure 3 (flaxseed-protected) show the surface behavior of coconut fiber after being immersed in a Ca(OH)2 solution for 0, 7, 21, and 28 days.
Figure 2a and Figure 3a show the surface characteristics of the coconut fibers before contact with Ca(OH)2, which were protected with hydrophobic agents such as paraffin wax and linseed oil, respectively. A good protection of the fibers was noted, which guarantees a good performance of the reinforced mortar. Figure 2b shows the condition of the fiber once the 7 days submerged in Ca(OH)2 had elapsed, where the presence of calcium hydroxide (small white areas) could be seen in the small pores of the fiber. These places were exposed to the alkaline environment of the solution, presenting weight loss and obtaining a percentage of chemical resistance of 67.66%. After 21 days (Figure 2c), greater degradation was observed compared with what was observed after 7 days, and it was noted that the small fibers were mostly coated with calcium hydroxide. The chemical resistance obtained in this case was 60.97%. However, after 28 days it was noticed that the white areas were sparse, which is because the impregnating substance coated most of the surface of the fiber, preventing the alkaline medium of the solution from completely degrading the fiber. The presence of precipitated Ca(OH)2 crystals on the surface was noted. The percentage of chemical resistance for this sample was 82.68%. As for the coconut fibers coated with linseed oil (Figure 3), the surface condition of the fiber was observed after 7 days of immersion in Ca(OH)2 (Figure 3b), where it was seen that there was little degradation since the presence of white regions was lower; therefore, it can be said that the linseed oil waterproofed a large part of the surface of the strands of the coconut fibers, preventing weight loss.
This result can be seen in the chemical resistance of the fiber, which was 84.48%. After 21 days (Figure 3c), it was noted that some regions remained exposed to the alkaline medium of the solution, where the concentration of Ca(OH)2 on the surface of the fiber increased. It should be noted that a few areas were degraded by the solution, obtaining a chemical resistance of 82.97%. However, after 28 days of immersion in the calcium hydroxide solution, it was observed that the fiber had degraded. Most of the fiber was coated by calcium hydroxide crystals, presenting a considerable weight loss and degradation of the fiber. The percentage of chemical resistance was 31.87%. In conclusion, after 28 days of immersion in Ca(OH)2, paraffin wax showed the best protection to the coconut fibers due to the better interaction between their molecular structures given that they present similarities in the composition of their chains (long chains). The molecular chains of coconut fibers are of the glucose type, while those of paraffin wax are of the hydrocarbon type [14].
Figure 4 presents the FTIR spectrum of the coconut fiber. Figure 4a shows the presence of five characteristic absorption peaks: Peak 1 at 3407 cm−1 (associated with polysaccharides such as cellulose, lignin, and hemicellulose) [15,16]; Peak 2 at 2932 cm−1 (associated with stretching of C≡C) [17]; Peak 3 at 2357 cm−1 (associated with stretching of the O-H carboxylic acid); Peak 4 at 1657 cm−1 (associated with the RNH”R groups of secondary amines) [18,19]; and Peak 5 at 1080 cm−1 (associated with the presence of fluoroalkanes) [17].
Figure 4b shows the behavior of the infrared spectra of coconut fibers coated with kerosene and immersed in Ca(OH)2 for 7, 21, and 28 days. The presence of different peaks associated with lignin phenols and hydroxyls of cellulose and hemicellulose (Peak 1) was noted [20]. Peaks associated with the symmetric elongation of C-H bonds (peak 2) [21], the asymmetric CH2 strain of cellulose (2850 cm−1) corresponding to CH2-CO, were also observed. Peak 4 shows a series of intense and sharp bands representing the bending of all active methylene and peaks belonging to the stretching of the nitro group—CNO2 (878 cm−1). Similarly, the presence of fluoroalkanes (Peak 5) was noted. Peak 3 (2356 cm−1) was only found in samples taken at 21 and 28 days [18,19,22,23,24].
Figure 4c shows the infrared spectra of coconut fiber coated with linseed oil after being immersed in Ca (CO)2 for 7, 21, and 28 days. Peaks 1 to 5 showed similar behaviors to those obtained in the paraffin wax-coated samples (Figure 4b). Marked differences were observed in the peaks below 1000 cm−1 in which the peaks belonged to the stretch of the nitro group CNO2 (889 cm−1), the peak associated with the C-H bond (695 cm−1). After 28 days, peaks associated with the vibrations of the carbonyl groups of hemicellulose with the asymmetric vibrations of methylene and its peaks were observed [18,19,23]. It is worth highlighting that Peaks 1 and 2 did not show significant changes after 7, 21, and 28 days, which would indicate that no degradation occurred.

3.1.2. Thermal Analysis

Figure 5 summarizes the thermogravimetric behavior of the coconut fiber before being coated with the hydrophobic substances used in this study. Three important stages of weight loss with increasing temperature were identified. The first stage (25–114.4 °C), which corresponded to the loss of moisture in the sample (7.28%) [25,26]. The second stage (114.4–336.9 °C), which corresponded to the degradation of hemicellulose, cellulose, and part of the lignin [27]; this stage represented 52.67% of the weight loss of the sample and the volatile products generated during decomposition were water, CO, and CO2 [25]. The third stage (336.9–739.7 °C) corresponded to the decomposition of cellulose and the remaining lignin in the coconut fiber [22,28] and represented 22.16% of the weight loss of the sample.
Jimenez et al. [29] stated that even at temperatures above 550 °C, fiber degradation processes are the product of the deterioration of some polysaccharides, lignin, and certain inorganic substances. Using the derivative thermogravimetry (DTG) technique, the change in mass of the uncoated coconut fiber was analyzed with respect to time, presenting two representative peaks: the first at 195 °C (decomposition of hemicellulose) and the second at 319 °C (decomposition of cellulose). The second peak showed the highest rate of fiber degradation [30,31].
Figure 6 summarizes the thermogravimetric behavior of coconut fiber coated with linseed oil and paraffin wax compared with the unprotected material. The presence of four regions of weight loss can be observed in Figure 6a. The first zone represented the humidity loss of the material (20–167 °C), where 5.5% loss in the linseed oil-coated fiber and 5.7% loss in the paraffin wax-coated fiber were obtained.
The second zone (167–417 °C) showed the range of decomposition of cellulose, hemicellulose, part of the lignin, carbohydrates, sugars, starches, etc. A total of 31.4% weight loss in the linseed oil-coated fiber and 38.3% in the paraffin wax-coated fiber were obtained. The third zone (417–492 °C) corresponded to the decomposition of hemicellulose with weight losses of 30.6% by weight of the fiber coated with linseed oil and 34.2% of the fiber coated with paraffin wax. Finally, the fourth zone (492–687 °C) showed the range of cellulose decomposition and the final residue, which according to Jimenez et al. [29], could be attributed to the final degradation of lignin.
When evaluating the variation in the coconut fiber weight with time as a function of temperature (Figure 6b), a significant improvement in the thermal stability of the fibers when coated was observed due to the inhibition of hemicellulose decomposition (near 195 °C). The sample of coconut fiber coated with linseed oil showed five temperature peaks, a peak at 74 °C for water vaporization, a peak at 308 °C representing the simultaneous degradation of the main components of the fibers, and three peaks at 470 °C, 547 °C, and 634 °C (linseed oil decomposition). For the paraffin coconut fiber sample, it was observed that five peaks of maximum weight loss were generated, which corresponded to the temperature of 75 °C, 308 °C, 472 °C, 543 °C, and 613 °C (paraffin wax decomposition).

3.2. Mechanical Evaluation

3.2.1. Compressive Strength

The physical and mechanical properties of cement-based composites that are reinforced with natural fibers can be affected by many factors such as (1) the characteristics of the fibers including the type, surface properties, length, and weight percentage used [32]; (2) nature of cement and mix design; and (3) shape, casting, and curing of the composites [33]. It is important to highlight that all of the parameters involved in the compatibility between the fiber and the cement matrix always seek the most homogeneous possible distribution of the reinforcement fibers, which greatly impacts the mechanical properties of the material.
Figure 7 shows the results obtained when mortars reinforced with fibers coated with hydrophobic substances such as paraffin wax and linseed oil were subjected to compression. A better compression behavior of the mortars reinforced with coconut fibers coated with paraffin wax (Figure 7a) was clearly observed than those obtained in the mortars reinforced with coconut fibers coated with linseed oil (Figure 7b) after 28 days of curing. This behavior can be explained by the capacity of paraffin wax to reduce the water absorption capacity of the coconut fiber by modifying the physicochemical characteristics of the fiber/mortar interface. According to Figure 7a, the highest compressive strength was obtained by adding coconut fibers that were 1 cm in length coated with paraffin wax in proportions of 0.5% to the mortar (see Figure 7c). The maximum value reported was 13.08 MPa. A similar behavior in compressive strength was reported by Osorio et al. [6] in 2007 when using 0.5% bagasse fibers treated in 5% Ca(OH)2 for 24 h.
Fiber size determines the arrangement and alignment of a reinforcement material, with short fibers being randomly distributed while long fibers are more regularly arranged. When a unit axial load aligned parallel to the direction of the fibers was applied, the maximum strength of the mortar was obtained. In this work, the highest compressive strengths were obtained with the use of short fibers, which in their distribution presented an isotropic behavior to the applied mechanical stresses. Fujiyama et al. (2014) [34] found that the addition of sisal fibers with different lengths did not produce an increase in the compressive strength of mortars. However, they found that long fibers negatively affected the compressive strength compared with short fibers, attributing it to the increase to the porosity of the mortar. Lorenzia et al. (2024) [35] studied mortars reinforced with 2.9 wt.% coconut fiber with and without boiling pretreatment and found that after 63 days, all mortars containing boiled or unboiled fiber had slightly higher compressive strengths than the control mortar.
Another important factor in the mechanical characteristics of a composite material is the proportion of the reinforcing agent. Aziz et al. [32] reported that when a high amount of fiber is used during the mortar preparation process, it tends to clump, which makes the mixing process more difficult, generating adherence between the fibers and the matrix and decreasing its mechanical strength, since it can increase the porosity of the material [36,37]. In addition, a higher fiber content in the mortar has a significant effect on water absorption by the material [38]. Figure 7b shows an adverse effect of the coconut fiber-reinforcement coated with linseed oil on the compressive strength compared with the reference sample (see Figure 7d). This behavior may have been due to the greater deterioration of the fiber due to low protection by the linseed oil, which allowed for a greater negative effect of the alkaline agents of the cement, reducing the adherence of the fibers to the cementitious matrix generating spacings in the fiber–matrix interface, and producing a lower compressive strength of the material due to the reduction in the compactness of the cement [6]. Another possible cause of the compressive behavior of the material under study was the bleeding phenomenon that occurs when a high water–cement ratio is used during the mortar generation process [14].

3.2.2. Flexural Strength

Figure 8 shows the flexural behavior of mortars reinforced with coconut fibers coated with paraffin wax and linseed oil. A better flexural behavior was observed in the fiber-reinforced mortars impregnated with paraffin (Figure 8a) compared with those protected with linseed oil (Figure 8b). This behavior may be due to the lower water absorption capacity of the fiber when coated with paraffin wax, allowing for a lower degradation of the reinforcement material in the presence of the alkaline environment of the cement, favoring a higher adhesion between the fiber and matrix and generating a higher flexural strength, as reported by Juárez et al. (2004) [14].
According to the results presented in Figure 8, it was observed that after 28 days of mortar curing, the highest flexural strengths were obtained compared with the reference sample (3.09 MPa) with the addition of 0.5 wt.% of coconut fiber paraffin wax coated reinforcement. The highest values reported were 4.432 MPa (length 1 cm) and 3.968 MPa (length 2 cm). Fiber length is an important variable in the flexural behavior of the material, and the presence of long fibers allows for an alignment toward a specific direction, however, a unidirectional orientation would generate an anisotropic material, which would result in low mechanical properties under loads parallel to the fibers [39] (see Figure 8c,d). Due to this, mortars reinforced with 1 cm fibers in a proportion of 0.5 wt.% (short fibers) were aleatory aligned, showing an isotropic behavior under mechanical stresses. Juarez C. et al. [16] reported increases in the flexural strength of concrete reinforced with 0.5% by volume of lechuguilla fiber; this mechanical strength decreased as the volume of the reinforcing fiber increased. Quintero et al. [38] showed that the addition of coconut fiber improved the flexural strength of concrete when its volume percentage was 0.5% by volume and 5 cm in length. In addition to this, Zou et al. [4] showed that the addition of coconut fibers to a phosphorus and magnesium-based cement significantly improved the flexural strength, reaching 13.49 MPa (15.7% higher than that obtained in the unreinforced material). It is worth noting that the incorporation of coconut fibers to cement-based materials contributes to waste recycling.
The enhancement in flexural strength can be attributed to the ability of fiber reinforcements to increase the toughness of the matrix through various mechanisms. Cracks that form in the matrix are transferred to the fibers, which absorb energy and impede crack propagation. However, if the bond between the matrix and the fiber is weak, fiber detachment may occur, which increases the probability of fracture [38]. In such cases, the crack is forced to continue its progression around the fibers, a process that consumes energy and increases the fracture toughness. In addition, when a crack begins to form in the matrix, the intact fibers can exert compressive forces that prevent the crack from opening completely [38].

4. Conclusions

When evaluating the mechanical behavior of the structural mortar reinforced with coconut fibers, an increase in compressive and flexural strength of 84.27% and 43.32%, respectively, was obtained in comparison with the unreinforced mortar. This indicates that this type of fiber is a good alternative as a reinforcing agent, especially when the fibers are added in low proportions (0.5% by weight), since they do not hinder mixing. As for the short fibers (1 cm), they produced an isotropic behavior in the material since they were randomly aligned, improving the mechanical resistance.
By means of thermogravimetric analysis, it was possible to determine the presence of four stages during the thermal degradation of coconut fibers: (1) loss of fiber humidity; (2) presence of extractives in the sample; (3) thermal degradation of cellulose and hemicellulose; and (4) degradation of lignin. In addition, it was found that the use of paraffin wax as a protective agent for the fibers increased their chemical resistance by reducing their water absorption capacity, generating good protection against the alkaline environment of the cement. This hydrophobic protection showed an improvement in the thermal behavior of the fiber.

Author Contributions

Conceptualization, M.-J.M.-A., O.-F.H.-C. and C.-A.P.-Y.; Methodology, O.-F.H.-C. and M.-J.M.-A.; Formal analysis, M.-J.M.-A.; Investigation, M.-J.M.-A., O.-F.H.-C. and C.-A.P.-Y.; Writing—original draft, M.-J.M.-A. and O.-F.H.-C.; Writing—review and editing, M.-J.M.-A., O.-F.H.-C. and C.-A.P.-Y. All authors have read and agreed to the published version of the manuscript.

Funding

The APC was funded by Universidad del Atlántico.

Data Availability Statement

The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Thanushan, K.; Sathiparan, N. Mechanical performance and durability of banana fibre and coconut coir reinforced cement stabilized soil blocks. Materialia 2022, 21, 101309. [Google Scholar] [CrossRef]
  2. Agopyan, V.; Savastano, H., Jr.; John, V.; Cincotto, M. Developments on vegetable fibre-cement based materials in São Paulo, Brazil: An overview. Cem. Concr. Compos. 2005, 27, 527–536. [Google Scholar] [CrossRef]
  3. Varghese, A.; Unnikrishnan, S. Mechanical strength of coconut fiber reinforced concrete. Mater. Today Proc. 2023. [Google Scholar] [CrossRef]
  4. Zou, Q.; Ye, X.; Huang, X.; Zhang, W.; Zhang, L. Influence of elevated temperature on the interfacial adhesion properties of cement composites reinforced with recycled coconut fiber. J. Build. Eng. 2014, 98, 111270. [Google Scholar] [CrossRef]
  5. Crucho, J.M.L.; de Picado-Santos, L.G.; das Neves, J.M.C. Assessment of the durability of cement-bound granular mixtures using reclaimed concrete aggregate and coconut fiber. Constr. Build. Mater. 2024, 441, 137550. [Google Scholar] [CrossRef]
  6. Osoriosaraz, J.A.; Varón Aristizabal, F.; Herrera Mejía, J.A. Comportamiento mecánico del concreto reforzado con fibras de bagazo de caña de azúcar. Dyna 2007, 74, 69–79. [Google Scholar]
  7. Coutts, R.S.P. A review of Australian research into natural fibre cement composites. Nat. Fibre. Reinf. Cem. Compos. 2005, 27, 518–526. [Google Scholar] [CrossRef]
  8. Bentur, A.; Sidney, M. Fibre Reinforced Cementitious Composites; CRC Press: Boca Raton, FL, USA, 2014. [Google Scholar]
  9. de Guzman, D.S. Tecnología del Concreto y del Mortero; Bhandar Editores LTDA: Bogota, Colombia, 2001. [Google Scholar]
  10. Llerena Encalada, A. Estudio de Compuestos Cementicios Reforzados con Fibras Vegetales. Master’s Thesis, Universitat Politècnica de Catalunya, Barcelona, Spain, 2014. [Google Scholar]
  11. NTC 3546; Norma Técnica Colombiana. Concretos. Métodos de Ensayo para Determinar la Evaluación en el Laboratorio y en obra, de Morteros para Unidades de Mampostería Simple y Reforzada. ICONTEC: Bogota, Colombia, 2003.
  12. I.N.V.E-324-07; Resistencia a la Flexión de Morteros de Cemento Hidraúlico. Instituto Nacional de Vías: Bogota, Colombia, 2007.
  13. Acevedeo de la Espriella, M.A.; Luna Velasco, M.S. Tratamiento Químicos Superficiales para el Uso de Fibras Naturales en la Construccioón: Concretos y Morteros; Monografia Título Ingeniero Civil; Universidad de Cartagena: Bolivar, Colombia, 2021. [Google Scholar]
  14. Juarez Alvarado, C.A. Concretos Base Cemento Portland Reforzados con Fibras Naturales (Agave lechugilla), Como Materiales para Construcción en México. Ph.D. Thesis, Universidad Autónoma de Nuevo León, St. Nicholas, Mexico, 2002. [Google Scholar]
  15. Bilba, K.; Arsene, M.-A.; Ouensanga, A. Study of banana and coconut fibers: Botanical composition, thermal degradation and textural observations. Bioresour. Technol. 2007, 98, 58–68. [Google Scholar] [CrossRef]
  16. Hernandez-Vidal, N.; Bautista, V.; Morales, V.; Ordóñez, W.; Osorio, E. Caracterización química de la Fibra de Coco (Cocus nucifera L.) de México utilizando Espectroscopía de Infrarrojo (FTIR). Ing. Región 2018, 20, 67–71. [Google Scholar] [CrossRef]
  17. Ceron Meneses, Y.P.; Alban Bolaños, P.; Grass Ramírez, J.F.; Camacho Muñoz, R. Caracterización física, química, térmica y mecánica de fibras de coco de la Costa Pacífica del Cauca con potencial como refuerzo de materiales compuestos de matriz polimérica. Biotecnol. Sect. Agropecu. Agroind. 2024, 22, 30–42. [Google Scholar]
  18. Contreras, J.; Trujillo, A.; Arias, O.; Perez, L.J.B.; Delgado, F.E. Espectroscopía ATR-FTIR de celulosa: Aspecto instrumental y tratamiento matemático de espectros. e-Gnosis 2010, 8, 1–13. [Google Scholar]
  19. Paola, R.; Valladares, S.; Pedro, O.; Gáscue, B.; Peña, G. Obtención de Celulosa Microcristalina a partir de Desechos Agrícolas del Cambur (Musa sapientum). Síntesis de Celulosa Microcristalina. Rev. Iberoam. Polímeros 2014, 15, 286–300. [Google Scholar]
  20. Luo, Z.; Li, P.; Cai, D.; Chen, Q.; Qin, P.; Tan, T.; Cao, H. Comparison of performances of corn fiber plastic composites made from different parts of corn stalk. Ind. Crops Prod. 2017, 95, 521–527. [Google Scholar] [CrossRef]
  21. Sanou, I.; Bamogo, H.; Sory, N.; Gansoré, A.; Millogo, Y. Effect of the coconut fibers and cement on the physico-mechanical and thermal properties of adobe blocks. Heliyon 2024, 10, e38752. [Google Scholar] [CrossRef] [PubMed]
  22. Olonade, K.A.; Savastano Junior, H. Performance evaluation of treated coconut fibre in cementitious system. SN Appl. Sci 2023, 5, 218. [Google Scholar] [CrossRef]
  23. Carrillo Navarrete, F. Caracterización Estructural de Fibras Lyocell y su Comportamiento Frente a Procesos de Degradación. Ph.D. Thesis, Universitat Politècnica de Catalunya, Barcelona, Spain, 2002. [Google Scholar]
  24. Ssemujju Lubowa, P.; Ndiritu, H.; Oketch, P.; Mutua, J. Coconut Fiber Pyrolysis: Bio-Oil Characterization for Potential Application as an Alternative Energy Source and Production of Bio-Degradable Plastics. World J. Eng. Technol. 2024, 12, 310–319. [Google Scholar] [CrossRef]
  25. Paricaguán, B.; Albano, C.; Palacios, J.; Torres, R.; Camacho, N.; Infante, J.; Alvarado, M. Degradación térmica de fibras de coco con tratamiento químico provenientes de mezclas de concreto (estudio cinético). Rev. Ing. UC 2013, 20, 60–67. [Google Scholar]
  26. Pineda Gomez, P.; Coral, D.F.; Rivera Ramos, D.; Rosales Rivera, A. Estudio de las propiedades térmicas de harinas de maíz producidas por tratamiento térmico-alcalino. Ing. Cienc. 2011, 7, 119–142. [Google Scholar]
  27. Ferreira, S.R.; de Andrade Silva, F.; Lima, P.R.L.; Toledo Filho, R.D. Effect of fiber treatments on the sisal fiber properties and fiber–matrix bond in cement based systems. Constr. Build. Mater. 2015, 101, 730–740. [Google Scholar] [CrossRef]
  28. Wei, J.; Meyer, C. Degradation rate of natural fiber in cement composites exposed to various accelerated aging environment conditions. Corros. Sci. 2014, 88, 118–132. [Google Scholar] [CrossRef]
  29. Jimenez, A.; Betancourt, S.; Gañán, P.; Cruz, L. Degradación térmica de fibras naturales procedentes de la calceta de plátano. (Estudio cinético). Rev. Latinoam. Metal. Mater. 2009, 29, 215–219. [Google Scholar]
  30. Juarez, C.; Valdes, P.; Durán, A. Fibras naturales de lechuguilla como refuerzo en materiales de construcción. Rev. Ing. Construcción 2004, 19, 83–92. [Google Scholar]
  31. Wei, J.; Meyer, C. Utilization of rice husk ash in green natural fiber-reinforced cement composites: Mitigating degradation of sisal fiber. Cem. Concr. Res. 2016, 81, 94–111. [Google Scholar] [CrossRef]
  32. Aziz, M.A.; Paramasivam, P.; Lee, S.L. Prospects for natural fibre reinforced concretes in construction. Int. J. Cem. Compos. Lightweight Concr. 1981, 3, 123–132. [Google Scholar] [CrossRef]
  33. Chakraborty, S.; Kundu, S.P.; Roy, A.; Adhikari, B.; Majumder, S.B. Polymer modified jute fibre as reinforcing agent controlling the physical and mechanical characteristics of cement mortar. Constr. Build. Mater. 2024, 49, 214–222. [Google Scholar] [CrossRef]
  34. Fujiyama, R.; Darwish, F.; Pereira, M.V. Mechanical characterization of sisal reinforced cement mortar. Theor. Appl. Mech. Lett 2014, 4, 061002. [Google Scholar] [CrossRef]
  35. Lorensia, L.; Hou, T. Effects of boiling and fiber length on the resistivity of coconut-fiber-reinforced mortar. Case Stud. Constr. Mat. 2024, 20, e03177. [Google Scholar] [CrossRef]
  36. Yan, L.; Kasal, B.; Huang, L. A review of recent research on the use of cellulosic fibres, their fibre fabric reinforced cementitious, geo-polymer and polymer composites in civil engineering. Compos. Part B Eng 2016, 92, 94–132. [Google Scholar] [CrossRef]
  37. Hwang, C.-L.; Tran, V.-A.; Hong, J.-W.; Hsieh, Y.-C. Effects of short coconut fiber on the mechanical properties, plastic cracking behavior, and impact resistance of cementitious composites. Constr. Build. Mater. 2016, 127, 984–992. [Google Scholar] [CrossRef]
  38. Quintero García, S.L.; González Salcedo, L.O. Uso de fibra de estopa de coco para mejorar las propiedades mecánicas del concreto. Ing. Desarro. 2011, 20, 134–150. [Google Scholar]
  39. Gonzalez Salcedo, L.O. Influencia de los Componentes del Concreto Reforzado con Fibras en sus Propiedades Mecánicas; Universidad Nacional De Colombia: Palmira, Colombia, 2013. [Google Scholar]
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Figure 1. Methodology for fiber preparation.
Figure 1. Methodology for fiber preparation.
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Figure 2. Surface behavior of paraffin-protected coconut fiber during the immersion process in Ca(OH)2 for (a) 0, (b) 7, (c) 21, and (d) 28 days.
Figure 2. Surface behavior of paraffin-protected coconut fiber during the immersion process in Ca(OH)2 for (a) 0, (b) 7, (c) 21, and (d) 28 days.
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Figure 3. Surface behavior of coconut fiber protected with linseed oil during the immersion process in Ca(OH)2 for (a) 0, (b) 7, (c) 21, and (d) 28 days.
Figure 3. Surface behavior of coconut fiber protected with linseed oil during the immersion process in Ca(OH)2 for (a) 0, (b) 7, (c) 21, and (d) 28 days.
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Figure 4. FTIR spectrum of the coconut fiber: (a) uncoated, (b) coated with paraffin, and (c) coated with linseed dipped in Ca(OH)2.
Figure 4. FTIR spectrum of the coconut fiber: (a) uncoated, (b) coated with paraffin, and (c) coated with linseed dipped in Ca(OH)2.
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Figure 5. Untreated coconut fiber breakdown thermogram.
Figure 5. Untreated coconut fiber breakdown thermogram.
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Figure 6. (a) TGA curve and (b) DTG curve of the paraffin wax- and linseed-coated coconut fibers.
Figure 6. (a) TGA curve and (b) DTG curve of the paraffin wax- and linseed-coated coconut fibers.
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Figure 7. Compression behavior of the fiber-reinforced mortars coated with (a) paraffin wax and (b) linseed oil. Mortar reinforced with 1 cm-0.5 wt.% of coconut fibers coated with (c) paraffin wax and (d) linseed oil subjected to the compression test after 28 days.
Figure 7. Compression behavior of the fiber-reinforced mortars coated with (a) paraffin wax and (b) linseed oil. Mortar reinforced with 1 cm-0.5 wt.% of coconut fibers coated with (c) paraffin wax and (d) linseed oil subjected to the compression test after 28 days.
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Figure 8. Flexural behavior of the fiber-reinforced mortars coated with (a) paraffin wax and (b) linseed oil. Mortar reinforced with 1 cm-0.5 wt.% of coconut fibers coated with (c) paraffin wax and (d) linseed oil subjected to the compression test after 28 days.
Figure 8. Flexural behavior of the fiber-reinforced mortars coated with (a) paraffin wax and (b) linseed oil. Mortar reinforced with 1 cm-0.5 wt.% of coconut fibers coated with (c) paraffin wax and (d) linseed oil subjected to the compression test after 28 days.
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Table 1. Design of the experiments implemented in this study.
Table 1. Design of the experiments implemented in this study.
Fiber TypeProtective SubstanceLength (cm)Percentage by WeightNumber of Specimens
Coconut fiberLinseed oil10.512
112
20.512
112
50.512
112
Paraffin wax10.512
112
20.512
112
50.512
112
Control mortar 6
Total150
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MDPI and ACS Style

Monsalve-Arias, M.-J.; Higuera-Cobos, O.-F.; Pedraza-Yepes, C.-A. Development of Structural Type Mortars Reinforced with Coconut (Cocos Nucifera) Fiber: Chemical, Thermal, and Mechanical Behavior. J. Compos. Sci. 2025, 9, 300. https://doi.org/10.3390/jcs9060300

AMA Style

Monsalve-Arias M-J, Higuera-Cobos O-F, Pedraza-Yepes C-A. Development of Structural Type Mortars Reinforced with Coconut (Cocos Nucifera) Fiber: Chemical, Thermal, and Mechanical Behavior. Journal of Composites Science. 2025; 9(6):300. https://doi.org/10.3390/jcs9060300

Chicago/Turabian Style

Monsalve-Arias, Mónica-Johanna, Oscar-Fabián Higuera-Cobos, and Cristian-Antonio Pedraza-Yepes. 2025. "Development of Structural Type Mortars Reinforced with Coconut (Cocos Nucifera) Fiber: Chemical, Thermal, and Mechanical Behavior" Journal of Composites Science 9, no. 6: 300. https://doi.org/10.3390/jcs9060300

APA Style

Monsalve-Arias, M.-J., Higuera-Cobos, O.-F., & Pedraza-Yepes, C.-A. (2025). Development of Structural Type Mortars Reinforced with Coconut (Cocos Nucifera) Fiber: Chemical, Thermal, and Mechanical Behavior. Journal of Composites Science, 9(6), 300. https://doi.org/10.3390/jcs9060300

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