Alfa Fibers Research Articles

Towards rural net-zero energy buildings through integration of photovoltaic systems within bio-based earth houses: Case study in Eastern Morocco

Off-grid rural electrification programs involving renewable energy provide effective ways to boost the availability of power in remote areas. Herein, the combination of local bio-based building materials with appropriate sizing of a photovoltaic (PV) system to achieve energy-efficient rural housing in developing countries is investigated. The study focused on the fabrication and laboratory testing of a building material incorporating plant fibers, followed by a feasibility analysis of an integrated stand-alone PV system. EnergyPlus software was used to assess the energy-saving potential of bio-based building envelopes, and Homer Pro software was used for techno-economic optimization. Using a case-study building, various configurations were evaluated in terms of levelized energy cost and net present cost. According to the experimental results, the inclusion of 8 wt% Alfa fibers in earth blocks led to a noteworthy enhancement in the thermal resistance and time lag of the building envelope. Specifically, the improvement ranged from 0.549 to 1.125 m2K/W and from 18.5–h to 23.2–h, respectively, compared to using earth alone. This improvement resulted in a substantial decrease in the building's annual energy consumption, with a reduction of 24.3% for heating and 26.7% for cooling. Furthermore, the techno-economic analysis revealed that the electricity provided by a PV-battery hybrid system was 100% renewable and emission-free, with an energy cost of approximately $0.218/kWh and a present net cost of $11,560.21 These findings indicated that combining available solar energy with locally produced bio-based construction materials could be a viable approach for achieving carbon neutrality and building energy-efficient ulta-low-cost rural housing.

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

Natural Cellulosic Alfa Fiber (Stipa Tenacissima L.) Improved with Environment-Friendly Treatment Cementitious Composites with a Stable Flexural Strength

Natural Cellulosic Alfa Fiber (Stipa Tenacissima L.) Improved with Environment-Friendly Treatment Cementitious Composites with a Stable Flexural Strength

Effect of treated Alfa fibers on hydration kinetics, mechanical, and adhesion properties of fiber cement composite

The addition of Alfa fibers into a cementitious matrix leads to a composite with improved mechanical properties – in particular, its flexural strength. However, Alfa fibers have been found to degrade over time, due to the highly alkaline environment of the cementitious medium. This study examined the effect of treatments applied to the Alfa fibers on the mechanical performances and adhesion of the cementitious composite. Treatments of the surface of the Alfa fibers (alkaline and hydrothermal treatments, coating with sulfoaluminate cement, ultrasound and enzymatic treatments) were applied, with the aim of improving the behavior in the long term. The raw and treated Alfa fibers were incorporated into cement mortars, at different lengths (10 and 20 mm), at an addition rate of 1% vol. After 90 days, an improvement in flexural strength was observed in the mortars with 1% vol. of treated fibers; contrary to untreated fibers. The alkaline and hydrothermal treatments are the most effective of the bunch. An increase in the strengths of 44% and 32% respectively was noted, in comparison to untreated fiber. This finding was confirmed by a modification in the hydration reactions of the composites. A compatibility factor between the fiber and mortar was determined, showing that composites with Alfa fibers having undergone alkaline and hydrothermal treatments are more compatible with the mortar. To measure the interactions (shear stress) between the Alfa fiber and the cement mortar, a specific measuring device, based on a fiber immersed in mortar, was put in place. An increase in shear stress with fibers after treatment, suggesting that the fiber/mortar adherence properties are improved.

A facile preparation strategy and characterization of polymer composite-based on polycaprolactone and alfa fibers/graphene nanoplatelets hybrids

This work aims to assess the potential of the hybrid filler based on alfa fibers and graphene nanoplatelets (AF-GNPs) at different ratios on the features the poly(ε-caprolactone) (PCL) matrix using FTIR, RAMAN, TGA and mechanical analyses. The prepared composites through mold casting displayed good thermal behavior compared to pure PCL for which the sample that contains 5 % of the filler exhibits the highest thermal stability. Moreover, the incorporation of 5 % (AF-GNPs) leads to an increase of the tensile strength of the PCL from 13.23 to 14.18 MPa with a Young's Modulus enhancement from 248.75 to 431.15 MPa. Such composites provide an eco-friendly alternative to conventional, petroleum-based and non-renewable composites for numerous uses.

Incorporating vegetal fibers for sustainable sandy soil

Incorporating fibers into the soil is a reinforcement remediation technique to improve its physical and mechanical properties. Depending on the type of fibers, synthetic fibers, have negative impacts on the environment linked to the waste of their chemical industry. Currently, vegetal fibers consider an economic and ecological alternative to soil reinforcement. Therefore, this study aims to evaluate the influence of two types of randomly distributed fibers (Alfa and Sisal fibers) on the mechanical properties of sandy soil. Direct shear tests were performed on Chlef sand at relative density (Dr = 75% and 40%) and of fiber contents varying from 1, 2, 3 and 4% for sand samples reinforced with Alfa fibers and 0.1, 0.3, 0.5 and 0.7% for sand samples reinforced with Sisal fibers. The test results show that the inclusion of vegetal fibers in sandy soil improves the peak and residual shear strength. In addition, soil resistance was found to attain a maximum with the optimums of 0.7% for sisal fiber content and 3% for Alfa fibers.

Hybrid carbonaceous adsorbents based on clay and cellulose for cadmium recovery from aqueous solution.

The current work describes the synthesis of carbonaceous composites via pyrolysis, based on CMF, extracted from Alfa fibers, and Moroccan clay ghassoul (Gh), for potential use in heavy metal removal from wastewater. Following synthesis, the carbonaceous ghassoul (ca-Gh) material was characterized using X-ray fluorescence (XRF), Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX), zeta-potential and Brunauer-Emmett-Teller (BET). The material was then used as an adsorbent for the removal of cadmium (Cd2+) from aqueous solutions. Studies were conducted into the effect of adsorbent dosage, kinetic time, initial concentration of Cd2+, temperature and also pH effect. Thermodynamic and kinetic tests demonstrated that the adsorption equilibrium was attained within 60 min allowing the determination of the adsorption capacity of the studied materials. The investigation of the adsorption kinetics also reveals that all the data could be fit by the pseudo-second-order model. The Langmuir isotherm model might fully describe the adsorption isotherms. The experimental maximum adsorption capacity was found to be 20.6 mg g-1 and 261.9 mg g-1 for Gh and ca-Gh, respectively. The thermodynamic parameters show that the adsorption of Cd2+ onto the investigated material is spontaneous and endothermic.

Starch biocomposites based on cellulose microfibers and nanocrystals extracted from alfa fibers (Stipa tenacissima)

Cellulose-based biopolymers have emerged as one of the most promising components to produce sustainable composites as a potential substitutes to fossil-based materials. Herein, the aim of this study is to investigate the reinforcing effect of cellulose microfibers (CMFs) and cellulose nanocrystals (CNCs), extracted from alfa fibers (Stipa tenacissima), on the properties of starch biopolymer extracted from potato. The as-extracted CMFs (D = 5.94 ± 0.96 μm), CNCs (D = 14.29 ± 2.53 nm) and starch were firstly characterized in terms of their physicochemical properties. Afterwards, CMFs and CNCs were separately dispersed in starch at different concentrations, and their reinforcing effects as well as the chemical, thermal, transparency and mechanical properties of the resulted starch-based films were evaluated. Thus, CMFs and CNCs incorporation into starch resulted in a minor impact on the films thermal stability, while a considerable impact on the transparency property was observed. In terms of mechanical properties, the addition of up to 20 wt% CMFs reduced the film's elongation but drastically increased its stiffness by 300 %. On the other hand, in the case of CNCs, a loading of 10 wt% was found to be the most effective in increasing film stiffness (by 57 %), while increasing the loading up to 20 wt% CNCs enhanced the film's ductility (strain-to-failure) by 52 %. This study showed that introduction of cellulosic fibers having different sizes into starch can produce biocomposite materials with a wide range of properties for food packaging application.

"EFFECT OF ALKALINE TREATMENT TIME ON FLEXURAL PROPERTIES OF ALFA FIBER/UNSATURATED POLYESTER COMPOSITE "

Environmental and energy conservation pressure has led to a dramatic increase in the need for economically feasible lightweight materials that can be better substituted for non-biodegradable materials in reinforced composites. To this end, this study examines composite materials prepared from unsaturated polyester resins reinforced with treated and untreated Alfa fibers. Fiber treatment was carried out by NaOH solution of 5% concentration at different times (1, 3, 5 and 24 h). The strength and flexural modulus of the composites were evaluated according to the ASTM D790 test method. The analytical results indicate that the fibers’ alkaline pretreatment time had a positive influence on the mechanical properties of the composites.

Potential of using Alfa grass fibers (Stipa Tenacissima L.) to remove Pb2+, Cu2+, and Zn2+ from an aqueous solution

ABSTRACT This study used alfa grass fibres as a natural low-cost adsorbent to remove lead, copper, and zinc ions from aqueous solutions. The adsorbent was characterized by FTIR, SEM, BET surface area, ATG, and XRD techniques. The effects of pH, contact time, initial metal concentration, and adsorbent dosage on the adsorption efficiency were evaluated in batch experiments. The results showed that the adsorption of all metals was fast, and optimal removal efficiency was achieved within 25 min of contact time using 5000 mg/L of Alfa fibres at pH 6.3. The adsorption selectivity order was Pb2+ > Cu2+ > Zn2+ with Pb2+ removal efficiencies up to 97.6%. The adsorption kinetics were best explained by a pseudo-second-order kinetic model. The experimental adsorption data fitted very well with the Langmuir isotherm model, and less well with the Freundlich and Temkin isotherm models. The maximum adsorption capacities were respectively 14.492, 11.904, and 8.695 mg/g for Pb2+, Cu2+, and Zn2+. The results of this study indicated that Alfa fibres could be used as effective adsorbent for the removal of Pb2+, Cu2+, and Zn2+ from aqueous solutions.

Mechanical and morphological characterization of recycled HD-PE bio-composites based on alfa fibers and natural pozzolan

Abstract In this research work, waste plastic bottle caps made of high-density polyethylene (HD-PE) were reincorporated as a matrix and reinforced by alfa short fibers and natural pozzolan particles. Using different weight percentages of both fillers of 5 wt% up to 30 wt%, three types of bio-composite materials have been produced; alfa short fibers/HDPE, pozzolan particles/HDPE, and alfa fibers pozzolan/HDPE. Specimens for each type of the biocomposites were prepared through the compression molding method. The objective of this study is to investigate the effect of different content of alfa short fibers and pozzolan particles on the mechanical and morphological properties of the recycled HDPE matrix. Tensile test results revealed an enhancement in the mechanical properties for the three types of the biocomposites, an increase in tensile strength reached the maximum of 3573 MPa plus an interesting improvement in Young’s modulus with a maximum value of 3696 MPa. The toughness of the neat recycled HD-PE decreased by 212% by adding the natural filler whereas the modulus of resilience exhibited an increase of 138% compared to the neat recycled HD-PE. Therefore, the good rheological behavior of these bio-composites makes it possible to produce competitive materials and allows the reduction of plastic waste in the environment.

Elaboration of carboxylated cellulose nanocrystals filled starch-based adhesives for the manufacturing of eco-friendly particleboards

• Carboxylated cellulose nanocrystals (C-CNCs) were prepared from alfa fibers. • The potential of C-CNCs as nano-reinforcement for starch adhesives was assessed. • Formulated resins containing up to 2% of C-CNCs were used in particleboards. • Panels containing 1% of C-CNCs exhibited the best mechanical properties. • 1% of C-CNCs improved the physical and the water resistance properties of panels. The current work aims to assess the nano-reinforcing effect of carboxylated cellulose nanocrystals (C-CNCs) from alfa fibers in the development of corn starch-mimosa tannin bio-adhesives for the manufacturing of eco-friendly particleboards. C-CNCs were prepared through a hydrolysis process using mixed acid system of citric acid and hydrochloric acid and displayed an aspect ratio of 67.8, a crystallinity of 85 %, a zeta potential value of −38 mV and a carboxylate groups content of 976.5 mmol /Kg. The effect of fibers content (0.5, 1, 1.5 %, and 2 %) on the mechanical properties of the prepared composites was assessed. The water resistance behaviour of glued panels with the optimal amount of C-CNCs was evaluated through the study of their physical properties and the contact angle measurement. It was found that 1 % of C-CNCs led to a significant strength and water resistance behaviour relative to starch adhesive alone. The present work showed, for the first time, a new pathway for C-CNCs evaluation as a binder in starch based-adhesive for the development of woody composites.

Effect of alfa fiber loading on the mechanical, physical and dielectric properties of epoxy-amine composite

In this work, a varied content of alfa fiber was used as reinforcement and epoxy resin as matrix material. In order to eliminate the amorphous part of the alfa fiber, the fibers are treated with 5% of sodium hydroxide solution and their weight fraction is varied between 10% and 30%. Dielectric and water characteristics of different content of untreated and alkali treated alfa reinforced epoxy matrix is carried out in order to determine the role of cellulosic fibers in electrical field. Then, the Fourier transform infrared (FTIR) is employed to analyze the chemical structure of epoxy resin before and after curing with amine hardener. FTIR and Differential Scanning Calorimetry analysis confirm that epoxy resin is completely cured with amine hardener at room temperature. For composites loaded with 30% treated and untreated alfa fiber, a decrease in tensile and dielectric properties has been obtained, this may be related to the random distribution of alfa fiber in the epoxy matrix. Scanning electron microscopy analysis highlight the microstructure of epoxy matrix and its composites. The bio composites elaborated on the basis of alfa fiber and epoxy matrix have good physical and dielectric properties can be applied in different fields.

Evaluation and Characterization of Randomly Oriented Alfa Fibers Reinforced Epoxy‐Amine Composites

AbstractThe main objective of this research is to examine the effect of various fiber content and alkali treatment on the thermal and mechanical properties of alfa fiber reinforced epoxy‐amine matrix‐based composites. The fibers are treated with 5% of sodium hydroxide solution and their weight fraction is varied between 10% and 30%. The flexural test is carried out to investigate the mechanical properties of composites and the results show that all composites exhibit higher mechanical properties than the neat epoxy‐amine. The decline of flexural behavior of all composites with the increasing of the filler (30%) content is due probably to the random dispersion of the fibers in the epoxy resin.

Experimental study on the properties of Alfa/wool woven fabrics reinforced epoxy composite as an application in wind turbine blades

Wind energy is the kinetic energy of wind transformed into electrical energy by a system known as a wind turbine. All of the different parts of a wind turbine, like blades, hub, gearbox, nacelle, and tower, blades are usually made of glass and carbon fibers for better strength, lower weight, and better resistance to corrosion. The main limitations of these materials are the availability, non-biodegradable, health hazards, and fabrication cost. The development of interwoven fabric based on natural fiber for composite production is a novel approach that can be adopted to address the challenges of the balanced mechanical properties of composites. In this paper, alfa and wool fibers were selected as reinforcing materials to develop four woven fabrics, and unsaturated low viscosity epoxy resin was chosen as the matrix, the wovens were produced using the weaving of taffetas technique. The vacuum molding process was adopted to produce the hybrid composite due to its superior advantages over the hand lay-up technique. Alfa fibers have been previously treated with various concentrations of NaOH (1, 2, 3 mol) for 2 h. The effect of the alkaline treatment on the interface fiber matrix is analyzed. The results of static tests on composites showed an improvement in the tensile and flexural strengths of composites reinforced with woven fabrics. The mechanical performances of Alfa/wool yarns and fabrics obtained allow us to predict the actual perspectives of substitution of glass fibers by natural fibers for the application in wind blades.

Potential use of Alfa fibers in construction material: Physico-mechanical and thermal characterisation of reinforced specimen

The viability of using Alfa fibers as reinforcement material for developing lightweight sustainable construction materials in compliance with the valorization of local by-products concept has been investigated in this work. The specimens were produced based on the mix of hydraulic lime binder (NHL5) and varied Alfa fiber amounts of 0 % (Control Specimen), 7 %, 11 %, and 15 % vol. as binder replacement. The hardened properties of Alfa reinforced specimens including dry density, porosity, compressive and flexural strengths, elastic behavior, and dry thermal conductivity at different temperatures were investigated. The results have indicated that the addition of Alfa induced a moderate reduction in compressive strength which in turn allows to increase the deformability of specimen. Therefore, the addition of Alfa fibers induces failure mode change of specimen from brittle to ductile behavior, which results in improvement of toughness capacity. Test-results also highlighted the flexural strength enhancement of reinforced specimen for optimal amount value of 7% fibers, which exhibits a typical “composite” behavior. The corresponding strengthening rate of 139.4 % higher is due to the several reinforcement mechanisms like the high tensile strength of Alfa fibers and their bond reinforcement to the binder matrix. This leads to promote the load transfer mechanism from binder matrix to fibers which results in supporting a part of applied load before post-cracking phase. However, the use of Alfa fibers will make the reinforced specimen performed as regards the thermal insulation, where the thermal conductivity-value satisfies the basic requirement for using the sample in lightweight construction field as insulating-bearing material, according to the RILEM “class III” recommendations.

Hygrothermal, mechanical and durability assessment of vegetable concrete mixes made with Alfa fibers for structural and thermal insulating applications

This paper focuses on developing suitable concrete composites incorporating Alfa fibers (AF) for use in insulation and structural applications. Five formulations were prepared using AF weight ratios ranging from 0 to 10 wt%. The mixtures’ performance was assessed in terms of thermal insulation, compressive and flexural strengths, abrasion, moisture sorption, and buffering capacities. The results show that increasing AF contents improve concrete's thermal insulation and sorption capacities while reducing its mechanical strengths. Whereas the durability tests highlight the reinforcement character of AF, revealing that an incorporation range of 0–5 wt% improves the abrasion resistance. Formulations with 5 wt% and 10 wt% AF resulted in vegetable concretes with an average compressive strength of 3.78–0.6 MPa, and a thermal conductivity value of 0.46–0.19 W/mK, respectively. Moreover, MBV tests showed that both mixtures are classified as “EXCELLENT” moisture regulators; therefore, they are appropriate as structural and insulating building materials with improved hygrothermal properties.

Tensile properties and micromechanical modeling of polypropylene composites reinforced with alfa fibers

The performance of polyolefin composite materials reinforced with lignocellulosic fibers in terms of properties and mechanical behavior is strongly influenced by the strength of the interphase between the matrix and the reinforcements. The creation of a strong interface is hampered by the hydrophilicity and hydrophobicity of the reinforcing material and that of the matrix, respectively. Alkali treatment and the addition of compatibilizers have been a common solution to solve the interfacial problem. In this work, untreated short alfa fibers, treated with 3% sodium hydroxide (NaOH), polypropylene (PP), and compatibilizer (MAPP) were extruded and then injection molded to obtain tensile specimens. The alfa fiber length distributions in the composite were obtained by dissolving the matrix of the composite in a Soxhlet apparatus to extract the fiber. The results obtained for the composite at 30% by weight and with a combined treatment (NaOH + MAPP), showed a higher tensile strength compared to untreated composites. In addition, the morphology and the chemical composition of the fiber were analyzed to further discuss the results of micromechanical models. The interfacial shear strength (τ) and orientation factor (η0) of the alfa fibers in the polypropylene matrix were determined during the analysis of the modified Kelly and Tyson model. The results obtained from these models showed that the ([Formula: see text]) of the combined treatment composites was higher compared to the untreated composites.

Experimental investigation on the mechanical behavior of concrete reinforced with Alfa plant fibers

Currently, the reinforcement of ordinary concrete with synthetic fibers poses ecological problems because the manufacturing process of these products is very polluting. Plant fiber composites are a new challenge for environmental protection. The present article aims to investigate the mechanical behavior of concrete reinforced with natural fibers, called alfa fibers. Compression and three-point bending tests have been performed on cubic and prismatic samples, respectively. Different fiber lengths (2.5, 5, and 8 cm) and content (0.6, 1.2, and 1.8%by volume) of alfa fibers have been used to examine their influence on the mechanical behavior of the fiber-reinforced concrete. The obtained results show that for a volume content of 1.2% of plant fibers of 5 cm length, the tensile strength of the reinforced concrete increases up to 54.41% compared to the ordinary concrete (BT). However, for content of 1.8% of fibers with 8 cm length, both the compressive and tensile strength of the reinforced concrete decrease slightly. At this level, an excess of both fiber content and their length produces the formation of voids within concrete. Moreover, such an excess made the hydration reaction slower. It is worth noticing that the orientation of fibers also plays a significant role in the nucleation and propagation of microcracks. The fibers arranged both horizontally and obliquely are more resistant to microcracking than those oriented in the loading direction.

Extraction and characterization of Alfa fibers and their use to produce Alfa/wool woven fabrics for composite reinforcement

Abstract Because of their appealing properties, such as biodegradability, high basic stiffness, low density, and low cost, natural fibers have begun to be used in a variety of applications. In comparison to synthetics, they are also reusable. The aim of this work is to develop new woven materials made of wool and Alfa fibers (Stipa-tenacissima). The extraction of Alfa fibers was achieved via alkaline treatment. The chemical composition, mechanical and physical properties of the extracted fibers were determined. Wovens were produced using the weaving of taffetas technique. This study presents a chemical, physical, morphological and mechanical characterization of Alfa/wool yarns and fabrics. The results show that the fabric made of fibers treated with 2 mol concentration of NaOH presents the greatest morphological structure and a higher degree of crystallinity due to the reorganization of the molecular chains that results in a better orientation of the fibers compared to other concentrations. On the other hand, the results of the tensile test show that the Young’s modulus of the Alfa/Alfa woven fabric is 8 ± 1.157 MPa in the weft direction, compared to the Alfa/wool woven fabric which has 6.06 ± 0.196 MPa and wool/wool woven fabric with 14.10 ± 1.369 MPa.