Fiber-matrix Interfacial Properties Research Articles

Surface Modification of Viscose Fabric with Silane Coupling Agents ‐ An Aspect of Comfort Properties

AbstractThe surface of viscose fabric was successfully functionalized with 3‐aminopropyltriethoxysilane (APS) and 3‐methacryloxypropyl‐trimethoxysilane (MPS) in order to optimize its physicochemical characteristics and textile performances. The functionalization was optimized with silane monomer concentrations of 600 and 300 %, ethanol‐water ratios of 60 : 40 and 80 : 20, pH 3.5 and 5, and reaction time of 90 and 60 min at 30 °C, for MPS and APS, respectively. The modified viscose fabric was characterized by FTIR, TGA, DTG, SEM, and EDX. The FTIR spectra of the MPS and APS‐modified fabrics showed additional peaks at 825 cm−1 for Si−CH2 group and 1208 cm−1 Si−O−CH3, respectively, indicating the incorporation of silane coupling agents. The degradation temperatures of MPS and APS‐modified fibres were 342 °C and 328 °C, respectively, while the value for untreated viscose fibre was 319 °C. The elemental percentage of silicone on viscose fibre after modification was 2.6 and 4.2 for MPS and APS respectively. The silane‐modified viscose fibre shown enhanced tensile strength, water repellency, thermal stability, wrinkle recovery, and improved colour fastness quality. These improvements were due to the flexibility of Si−O bond and the fibre matrix interfacial strength properties. Hence, the modification somewhat enhances the physico‐chemical characteristics of viscose fibre.

Production and characterization of sustainable biocompatible PLA/walnut shell composite materials

AbstractVarious treatments, such as alkaline and silane treatments, are commonly applied to natural fillers before production to enhance their quality, thermal stability, and water absorption capacity and improve the fiber–matrix interface properties. However, these processes are not environmentally friendly and may escalate the production cost of composites due to the need for additional processing steps in mass production. This study delves into the impact of untreated walnut shell (WS) filler material, employed in varying ratios (ranging from 10 to 40%) as a filler, on the mechanical, thermal, morphological, and physical properties of environmentally friendly polylactic acid (PLA) matrix composites. The experimental results highlight a significant decrease in tensile modulus by 28%, tensile strength ranging from 32 to 65%, a decrease in flexural modulus by 22%, and flexural strength ranging from 24 to 58% with varying WS filler ratios. Time-dependent water absorption and increased density were observed. FT-IR analysis indicates structural similarities, while DSC results show minimal effects on glass transition temperature and crystallinity. TGA results reveal reduced thermal stability with increasing WS content. SEM microstructure imaging demonstrates homogeneous WS particle distribution, but higher WS content leads to increased brittleness and diminished resistance properties. In conclusion, this study underscores the importance of balancing sustainability through WS filler ratios while preserving mechanical performance.

Effect of expansive agent on the mechanical properties of carbon-fibre-reinforced cement-based composites

Improving the flexural strength of a cement-based composite (CBC) reinforced with chopped carbon fibre (CF) while maintaining good workability is highly attractive for building high-rise large-span structures. A sulfoaluminate-based expansive agent (EA) was used to optimise the mechanical properties of CBCs reinforced with chopped CF by improving the fibre–matrix interfacial properties. The results of single-fibre pull-out tests showed that the interfacial frictional bond strength was improved by up to 51% owing to the addition of the EA, whereas the chemical debonding energy remained nearly unchanged. The effects of various concentrations of EA on the strength of cement pastes containing various lengths and volume fractions of CF were then investigated. The results indicated that, benefitting from the EA-induced high interfacial bond strength, the flexural strength and fluidity of the CF-reinforced cement paste could be further optimised. For example, utilising the EA, the flexural strength could be improved by 28% for a cement paste containing 0.5% CF of length 15 mm.

Reversible and irreversible effects on the epoxy GFRP fiber-matrix interphase due to hydrothermal aging

Epoxy R-Glass Fiber-Reinforced Polymer (GFRP) composite plates were hydrothermally aged at 60 °C for 23, 75, and 133 days. The water content reached 0.97 wt%, 1.45 wt% and 1.63 wt%, respectively. The studied GFRP matrix was inert to hydrolysis or chain scission, allowing for investigation of irreversible changes in the fiber-matrix interphase due to hydrothermal aging upon re-drying. During each period, a subset of the specimens was removed from the water bath and dried in a chamber. The weight loss upon drying was explained with epoxy leaching (impurities), sizing-rich interphase hydrolysis, glass fiber surface hydrolysis, accumulated degradation products escaping, and water changing state from bound to free. The influence of hydrothermal aging on the fiber-matrix interfacial properties was investigated. Lower interfacial strength of hydrothermally aged (wet) samples was attributed to plasticization of the epoxy, plasticization and degradation of the sizing-rich interphase (including formation of hydrolytic flaws), and hydrolytic degradation of the glass fiber surface. The kinetics of epoxy-compatible epoxysilane W2020 sizing-rich interphase hydrolysis provided an estimate of ca. 1.49%, 4.80%, and 8.49% of the total composite interphase degraded after 23, 75, and 133 days, respectively. At these conditions, the interface lost 39%, 48%, and 51% of its strength. Upon re-drying the specimens, a significant part of the interfacial strength was regained. Furthermore, an upward trend was observed, being 13%, 10% and 3% strength, respectively; thus, indicating a possibility of partial recovery of properties.

Effect of multi-scale reinforcement on fracture property of ultra-high performance concrete

This paper aims to achieve multi-scale crack control of concrete by using graphene oxide (GO) and macroscopic steel fiber in combination, and to reveal the multi-scale collaborative reinforcement mechanism of GO and steel fiber. A three-point bending fracture mechanics test was employed to analyze the macroscopic fracture properties of ultra-high performance concrete (UHPC) reinforced by GO, and a single fiber pull-out test was utilized to assess the impact of GO on the fiber–matrix interface properties. The results showed that 0.04% GO reinforced UHPC had the best fracture property, and steel fiber and GO showed good synergistic crack control effect. GO directly acted on controlling the cracking of concrete matrix at the nanoscale, thus improving the fracture energy of UHPC matrix by 14% from 73.08 N/mm to 83.39 N/mm. This micro-scale matrix reinforcement provided by GO further improved the pull-out property of steel fibers, and the pull-out energy dissipation of straight steel fibers and hook-end fibers was increased by 43.7% and 31.5%. A micromechanical prediction model for fracture energy of straight steel fiber UHPC was established, which could construct the quantitative relationship between UHPC fracture energy and micromechanical parameters. The model showed that the initial fiber–matrix bond strength (τ0) and slip hardening coefficient (k0) had a powerful influence on the UHPC fracture energy.

Effect of Fiber–Matrix Interface Friction on Compressive Strength of High-Modulus Carbon Composites

Carbon-fiber-reinforced polymers (CFRPs) enable lightweight, strong, and durable structures for many engineering applications including aerospace, automotive, biomedical, and others. High-modulus (HM) CFRPs enable the most significant improvement in mechanical stiffness at a lower weight, allowing for extremely lightweight aircraft structures. However, low fiber-direction compressive strength has been a major weakness of HM CFRPs, prohibiting their implementation in the primary structures. Microstructural tailoring may provide an innovative means for breaking through the fiber-direction compressive strength barrier. This has been implemented by hybridizing intermediate-modulus (IM) and HM carbon fibers in HM CFRP toughened with nanosilica particles. The new material solution almost doubles the compressive strength of the HM CFRPs, achieving that of the advanced IM CFRPs currently used in airframes and rotor components, but with a much higher axial modulus. The major focus of this work has been understanding the fiber-matrix interface properties governing the fiber-direction compressive strength improvement of the hybrid HM CFRPs. In particular, differences in the surface topology may cause much higher interface friction for IM carbon fibers compared to the HM fibers, which is responsible for the interface strength improvement. In situ Scanning Electron Microscopy (SEM)-based experiments were developed to measure interface friction. Such experiments reveal an approximately 48% higher maximum shear traction due to interface friction for IM carbon fibers compared to the HM fibers.

Utilization of novel stranded steel fiber to enhance fiber–matrix interface of cementitious composites

Reinforced materials with helically twisted geometries have been successfully applied in the concrete structures, owing to their superior mechanical properties and anchoring capabilities. Helically twisted types materials with diameters less than 1.0 mm might be an ideal type of fiber for cement-based materials reinforcing. In this article, a novel stranded steel (SS) fiber was first proposed and realized by simply cutting the commercial steel strands. The fiber–matrix interfacial properties and mechanical performance of steel fiber reinforced cementitious composites (SFRCC) were investigated. It was found that the SS fiber-cement matrix interface demonstrated superior interfacial bonding performance, as compared to those for the interface between hooked-end/straight fibers and cement matrix. For the mechanical properties of SFRCC, cementitious composites reinforced by SS fiber exhibited strikingly outstanding mechanical property as any other types of steel fiber with the same fiber amount. In conclusion, SS fiber may be more suitable for cementitious composite reinforcement than hooked-end and straight fibers.

Microscale evaluation of epoxy matrix composites containing thermoplastic healing agent

Among the strategies to produce healable thermosetting systems is their modification by the addition of thermoplastic particles. This work investigates the influence of poly(ethylene-co-methacrylic acid) (EMAA) on fiber-matrix interfacial properties of a glass fiber reinforced epoxy matrix composite. Epoxy-EMAA interactions were evaluated using differential scanning calorimetry (DSC) and infrared spectroscopy. The effects of EMAA on the epoxy network formation were evidenced by changes in glass transition temperature, cure kinetics and alteration of chemical groups during cure. Interfacial shear strength (IFSS) measurements obtained by single fiber pull-out tests indicate similar interfacial properties for pure and EMAA modified epoxy. Additionally, the potential for self-healing ability of an EMAA modified epoxy was demonstrated. However, IFSS after a healing cycle for the EMAA modified epoxy was lower as compared to the pure epoxy, because of the lower fiber-EMAA interfacial shear strength. So, thermoplastic healing agents has not only to fill cracks in the matrix material, but also have to be optimized regarding its interface properties to the reinforcing fibers.

Interfacial carbon fiber–matrix interactions in thermosetting composites volumetrically cured by electromagnetic fields

We present a novel out-of-oven method for curing carbon fiber reinforced composites (CFRCs) using radio frequency (RF) fields and assess the effects of fiber heating on the fiber–matrix interfacial properties. In this volumetric heating setup, thermal energy is generated by the carbon fibers interacting with the RF fields (1–200 MHz range) and drives the crosslinking reaction in the epoxy. To study the effect of RF heating and curing on the interfacial properties, we processed composites with carbon fibers embedded in thermosetting resin at varying target curing temperatures and tested these composites using nanoindentation and lap-shear tests that show comparable behavior to conventional oven-cured composites. Experimental characterization is coupled with finite element analysis and reactive molecular dynamics (ReaxFF) simulations to investigate and understand the interfacial properties. This investigation indicates that electromagnetic heating can be used to cure CFRCs rapidly without degrading the fiber–matrix interface.

Mechanical and fracture properties of fly ash-based geopolymer concrete with different fibers

The harm of cement has become a global concern due to its high energy consumption, environmental impact, and human health risks that come from continuous cement production. The development of fly ash-based geopolymer concrete (FGPC) was considered an effective and sustainable solution. However, FGPC is much more brittle than ordinary concrete, which needs to be solved urgently. Thus, the effects of three different fiber types, namely basalt fiber (BF), polyethylene polypropylene fiber (PF), and steel fiber (SF), on the mechanical properties and fracture toughness of FGPC were discussed in this study. The FGPC composites were designed and manufactured with fiber contents of 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.5%, 2.0% for each of the above fibers. Multiple items mechanical tests on cylindrical and notched prism specimens were conducted. In addition, the interfacial bond property between fiber and geopolymer matrix was evaluated by SEM and single-fiber pull-out tests (FPT). The results show that fiber type, fiber volume fraction and fiber-matrix interface properties contribute greatly to the mechanical properties and fracture behavior of FGPC members, thus improving the mechanical property and fracture toughness of FGPC. SEM and FPT analyses support these results. In addition, an energy dissipation model is proposed to consider the fracture process of the FGPC composites in more detail. Based on these studies, the improvement to the brittle behavior of GPC would be achievable.

A hybrid 1D/2D coating strategy with MXene and CNT towards the interfacial reinforcement of carbon fiber/poly(ether ether ketone) composite

Due to the inert carbon fiber (CF) surface and the poor wettability of CF with poly(ether ether ketone) (PEEK), the fiber-matrix interface bonding of CF/PEEK composite is relatively weak, which limits the mechanical performance of the composite. Herein, a complex sizing agent containing Ti3C2Tx MXene, carbon nanotube (CNT), and a dual compatibilizer of polyetherimide (PEI) was fabricated to graft on the CF surface. Compared with desized CF, the modified CF/PEEK composites showed a remarkable increase in flexural strength, flexural modulus, and interlaminar shear strength of 74.16%, 63.76%, and 62.79%, respectively. The improvement could be ascribed to the synergistic effects of multiple interactions, micromechanical interlockings, and substantially improved interfacial affinity by the hybrid grafting of MXene, CNT, and PEI. We also found that the interfacial failure mechanism changes from adhesive failure to cohesive failure with such a 1D/2D coating strategy. This facile and scalable approach demonstrates its potential for effectively improving fiber-matrix interfacial properties in CF/PEEK composites.

Nano-CaCO3 enhances PVA fiber-matrix interfacial properties: an experimental and molecular dynamics study

ABSTRACT The mechanical properties of fiber-reinforced concrete largely depend on its interfacial properties. Fibers with a low aspect ratio are often pulled out at the fracture surface, and the potential of fiber-reinforced concrete is far from being fully realized. This is because the fiber-matrix interface bond strength is weak, resulting in low fiber reinforcement efficiency， which is the main challenge for organic fiber reinforced concrete. To further optimize the reinforcing and toughening effect of fibers on concrete, in this study, nano-CaCO3 was used to treat PVA fibers by a sol-gel method, aiming to enhance the interfacial bonding properties of fiber-reinforced concrete. The mechanical properties test results show that the compressive strength and flexural strength of the modified PVA fiber reinforced concrete are increased by 8.1% and 35.95%, respectively. Finally, Molecular dynamics simulation results reveal the interaction mechanism between CaCO3 and the cement matrix-fiber interface. The CaC-S-H-OCaCO3 forms a high-strength interfacial connection and is stronger than the H bond formed at the C-S-H/PVA interface. Therefore, the C-S-H/CaCO3 interface interaction energy far exceeds that between C-S-H/PVA. Comprehensive analysis shows that nano-CaCO3 enhances the interfacial bonding performance of fiber-matrix, which has certain theoretical reference significance for developing high-performance fiber reinforced concrete.

Effect of glass fibre sizing on the interfacial properties of composites produced using in-situ polymerised Polyamide-6 transfer moulding

The fibre-matrix interfacial properties of glass-fibre/polyamide-6 (GF/PA-6) composites produced by thermoplastic resin transfer moulding (TP-RTM) were investigated. Two different fibre sizings were compared, a specially-developed novel reactive fibre sizing and a standard silane glass fibre sizing. Scanning electron microscopy, atomic force microscopy and a number of mass-loss techniques were employed to study the form, distribution, quantity and degradation temperature of the fibre sizings. Activated PA-6 monomer precursor materials with viscosities of ∼10 mPa s were injected into the glass-fibre fabrics, contained between heated press platens, and polymerisation occurred in-situ within several minutes. Glass-fabric laminates with fibre volume fractions of ∼53% and low void content were produced at a pressure of ∼4 bar, with the low viscosity of the monomer negating the need for expensive high-pressure injection. Similar quality between the laminates was demonstrated by measuring density, thickness, fibre volume fraction, void content and fibre bundle distribution. Transverse mechanical properties of the composites reinforced with the novel reactive sizing were 20–28% higher than those with the standard fibre sizings, demonstrating improved fibre-matrix interfacial properties. Average mode I fracture toughness was also measured to be 10–30% higher than with the standard fibre sizing. Scanning electron microscopy and 3D depth composition were used to investigate fracture surfaces and determine the surface roughness. The novel reactive fibre sizing resulted in improved fibre-matrix adhesion and improved fracture toughness.

PVA fiber reinforced cement composites with calcined cutter soil mixing residue as a partial cement replacement

In this paper, a cutter soil mixing residue (CSMR), which is a soil–cement solid waste, was calcined and then used as a partial cement replacement in polyvinyl alcohol fiber reinforced cement composites (PVA-FRCCs). The binder chemistry was characterized using XRD, TGA and FTIR. The fiber–matrix interfacial properties were examined with SEM. The composite mechanical properties, including compressive strength, flexural properties and tensile behaviors and fiber bridging stress-crack opening relationships, were investigated. Results showed that the calcined CSMR can produce additional hydrates to aid the strength gain and densify the fiber–matrix interface. With a cement replacement level up to 40%, the tensile strength was not compromised, while the tensile strain capacity significantly increased to a maximum value of 3.2%. The micromechanical analysis revealed that the improved strain capacity is mainly attributed to the optimized fiber–matrix interface yielding enhanced pseudo strain-hardening indices. The results obtained in this study indicate that calcined CSMR is an attractive novel supplementary cementitious material for developing greener strain-hardening cementitious composites.

Design, dynamic performance and ecological efficiency of fiber-reinforced mortars with different binder systems: Ordinary Portland cement, limestone calcined clay cement and alkali-activated slag

The dynamic mechanical properties and ecological efficiency of cement-based composites are of vital importance to the development of green building materials and dynamic loadings resistance. In this study, the dynamic mechanical properties, ecological and economic efficiency of fiber-reinforced mortars (FRMs) made with different binder systems, including ordinary Portland cement (OPC), limestone calcined clay cement (LC3), and alkali-activated slag (AAS), were compared. In addition, different rheological parameters were designed to evaluate the dynamic mechanical properties of FRMs. The fiber pull-out testing, Barrett-Joyner-Halenda (BJH) testing, and scanning electron microscope (SEM) were used to reveal the difference in the dynamic mechanical properties of FRMs made with different binder systems. The results showed that the loss factor of FRM made with LC3 was the highest, 70% and 150% higher than that made with OPC and AAS as the plastic viscosity of mixtures was at the same range. In addition, the loss factor of FRMs made with OPC and LC3 improved by 25% and 8.6% respectively as the plastic viscosity was improved to a higher level and caused more uniform fiber distribution. The fiber pull-out and microstructure testing indicated that FRM made with LC3 showed appropriate pore size distributions and good fiber-matrix interfacial properties. The ecological evaluation and cost analysis showed that the EE, ECO2e, and the cost of unit loss factor of FRM made with LC3 were the lowest among three kinds of mortars, showing 48369.1 MJ/m3, 6894.4 kgCO2/m3, and 20288.0 RMB/m3 respectively. Compared with FRM made with OPC, the above parameters were reduced by 55.8%, 66.9% and 46.0% respectively. Therefore, the FRM made with LC3 shows higher potential for designing green building materials with great dynamic loadings resistance, compared with FRMs made with OPC and AAS.

Vol4 num3-7 Study of the influence of surface treatments in kraft paper for the compatibilization with thermoplastic polymers

The transports industry has been presenting a set of solutions that integrates natural fibers and their compatibility with structural materials, like polymers. However, it is fundamental to ensure the fulfillment of mechanical requirements. One of the main reasons that is driving the use of this type of fibers, instead of synthetic fibers, is related with the some actual trends, such as weight reduction, which is linked with its lower density. Moreover, weight reduction also contributes, indirectly, to the sustainability and decrease of greenhouse gases emissions, since it makes possible to reduce the fuel consumption of transports.However, due to the different polarities verified between apolar thermoplastic polymers, such as polypropylene (PP), and natural fiber reinforcements, such as kraft paper, a study of the effect of physical and chemical surface treatments was carried out in order to verify their influence on the fiber-matrix interface properties. The physical process, corona treatment, was applied in the kraft paper with different discharge dosages, while the chemical treatment was performed through the use of several alkali solutions with different concentrations of NaOH. The obtained results from the performed tests shows that the alkali solution treatments improved, up to 57%, the mechanical properties of tensile strength and Young Modulus of the composite material, comparatively with the effect of corona treatment on its surface. These results induce an increase of interface compatibility between the matrix and kraft paper.

Combination usage of nano-SiO2-coated steel fiber and silica fume and its improvement effect on SFRCC

To further improve the fiber-matrix interfacial properties and enhance the macro-mechanical performances of steel fiber reinforced cement-based composite (SFRCC), two effective modification methods, nano-SiO2-coated steel fiber (NSF) targeted at the fiber-matrix interface and silica fume targeted at cement matrix, were tried to use together. The modification effects of NSF, silica fume and their combination usage were characterized and analyzed at multi-levels. Backscattered electron image analysis (BSE-IA) was used for micro microstructure characterization and the micro-hardness test was employed to evaluate the micro-mechanical property. A fiber pull-out test was drawn up and the interfacial bond properties, including the pull-out load-displacement curve, average bond strength and pull-out energy, were obtained. Flexural and compressive tests were conducted and the bending performance, flexural and compressive strength were focused on. The results show that the modification mechanisms of NSF and silica fume on SFRCC are quite different in that the one-way modification of NSF is from interface to bulk paste whereas that of silica fume is from bulk paste to interface. Both two methods improve the microstructure and performance of SFRCC effectively. Combination usage takes full advantage of the two modification methods, matches the improvement of different micro zones by two-way modifications, improves the interfacial bond properties and thereby achieves the further enhancement effect on macro performance.

Enhancing the PVA fiber-matrix interface properties in ultra high performance concrete: An experimental and molecular dynamics study

The interface properties largely determine the improvement effect of fibers on the cement-based matrix. In this work, nano-silica particles are employed to treat PVA fibers using a sol–gel method, aiming at enhancing interface properties in ultra-high-performance-concrete (UHPC). Based on a comprehensive analysis of SEM-EDS, TG, and Raman spectra, this modification measure has a relatively high coating efficiency and the nano-silica can be evenly distributed and stably adsorb on the surface of PVA fibers. Furthermore, by molecular dynamics simulations, the interaction mechanisms on the fiber-cementitious matrix interface are unraveled. The Ca (from matrix surface) -O (from silica) coordinations lead to chemical bondings, substantially stronger than H bonds formed on PVA/C-S-H interface. As a consequence, the pull-out of SiO2 modified fibers consumes significantly higher energy than pristine PVA. In conclusion, the coated nano-silica particles not only increase the surface roughness of PVA fibers, which correspondingly improves the physical friction and interlocking effect, but also react with Ca-containing phases in the cementitious matrix, forming new calcium silicate hydrate gels and filling in the cracks. These two mechanisms help increase the UHPC compressive strength by around 10% and the flexural strength by over 26%.

Processing of high weight fraction banana fiber reinforced epoxy composites using pressure induced dip casting method

The objective of this work is to realize new polymer composite material containing high amount of natural fibers as a bio-based reinforcement phase. Short banana fiber is chosen as a reinforcement material and epoxy polymer as a matrix material. About 77 wt.% of banana fibers were reinforced in the epoxy polymer matrix composite, using pressure induced fiber dipping method. Nanoclay particles were infused into the banana fibers to improve the fiber matrix interface properties. The nanoclay infused banana fiber were used to reinforce epoxy composite and its properties were compared with untreated banana fiber reinforced epoxy composite and banana fiber reinforced epoxy filled with nanoclay matrix composite. The surface characteristics of these composites were examined by electron microscope and the result shows well dispersed fibers in epoxy matrix. Thermal (thermogravimetry analysis and dynamic mechanical analysis), mechanical (tensile and fiber pullout) and water barrier properties of these composites were examined and the result showed that the nanoclay infused banana fiber reinforced epoxy composite shows better and improved properties. Improved surface finish composite was also obtained by this processing technique.

Characteristics of Interfacial Shear Bonding Between Basalt Fiber and Mortar Matrix.

Basalt fibers have been adopted as reinforcements to improve mechanical performance of concrete materials and structures due to their excellent corrosion resistance, affordable cost, and environmental-friendly nature. While the reinforcing efficiency is significantly dependent on fiber–matrix interfacial properties, there is a lack of studies focusing on the bonding behavior of basalt fibers in the mortar matrix. In this paper, a series of experiments were carried out to investigate the characteristics of single basalt fiber pulled out from the mortar matrix. Three embedment lengths and three types of mortar strength were considered. As references, the pull-out behavior of single polyvinyl alcohol (PVA) fiber and glass fiber in mortar matrix were also tested for comparison. Results from the pull-out test revealed that the average bonding strength is more effective than the equivalent shear bonding strength to illustrate the interfacial bond behavior of single basalt fiber in mortar matrix, which can be improved by either longer embedment length or the stronger mortar matrix. Finally, the tensile and compressive strengths of basalt/PVA/glass fiber-reinforced concrete (FRC) were measured to investigate the influence of interfacial shear bonding strengths. It was shown that, while PVA fiber developed the highest shear bonding strength with mortar, the basalt fiber exhibited the best reinforcing efficiency of FRC.