Microstructured Fiber Research Articles

Improving dispersion of recycled GFRP fiber in cement mortar with sodium hexametaphosphate

The dispersion of recycled glass fiber reinforced plastic (rGFRP) fibers in cement mortars has a significant impact on both the workability and mechanical properties of the composites. In this study, the dispersity of three types of rGFRP fibers was improved in two methods: Method 1: the dispersant (Sodium Hexametaphosphate, SHMP) was directly added into the mortar, and Method 2: the rGFRP fibers were pre-dispersed by the SHMP solution and then added into the mortar. The effect of the two fiber-dispersion methods on workability, mechanical properties, and microstructure of the rGFRP fiber reinforced mortars were investigated by Zeta potential test, mechanical tests, Mercury intrusion porosimetry and X-ray micro-CT analysis. The results showed that Method 2 had more significant improvement in mechanical strength than Method 1 for all types of rGFRP fiber reinforced mortar. The flexural strength of the mortars increased by 58.3%, 43.2% and 105.4% with 7.5 wt% GF1, GF2 and GF3 treated by Method 2, respectively, compared to their untreated counterparts. The pre-dispersion of the fibers with SHMP facilitated better dispersion of the large rGFRP fiber clusters in the mortar by increasing the surface charge of the fibers and enhancing repulsion between them, thus improving the mechanical performance of the mortar. The results of this study will promote the utilization of rGFRP fiber in construction materials.

Cross-sensitivity immune SPR sensor based on fan-shaped microstructured optical fiber for temperature and refractive index sensing.

To avoid coating and filling into the fiber holes, facilitate the phase-matching and eliminate cross-sensitivity problems, we propose a surface plasmon resonance sensor based on a fan-shaped microstructured optical fiber (MOF) for the simultaneous sensing of temperature and refractive index (RI). The fan-shaped structure is fabricated by polishing two sides of MOF with an angle of 120°. One side is coated with the gold film and polydimethylsiloxane layer for temperature sensing, and the other side is only coated with the gold film for RI sensing. The two sensing sides can support resonance peaks with two polarized directions at the angle of 120°, which are independent without cross-sensitivity. By monitoring the shifts of the two polarized peaks, our numerical results show that the temperature sensitivity is 2.932 nm/°C in the range of 30 °C to 40 °C, and RI sensitivity is 4235 nm/RIU in the range of 1.38 to 1.39, respectively.

Mechanical Performances Analysis and Prediction of Short Plant Fiber-Reinforced PLA Composites.

Plant fiber-reinforced polylactic acid (PLA) exhibits excellent mechanical properties and environmental friendliness and, therefore, has a wide range of applications. This study investigated the mechanical properties of three short plant fiber-reinforced PLA composites (flax, jute, and ramie) using mechanical testing and material characterization techniques (SEM, FTIR, and DSC). Additionally, we propose a methodology for predicting the mechanical properties of high-content short plant fiber-reinforced composite materials. Results indicate that flax fibers provide the optimal reinforcement effect due to differences in fiber composition and microstructure. Surface pretreatment of the fibers using alkali and silane coupling agents increases the fiber-matrix interface contact area, improves interface performance, and effectively enhances the mechanical properties of the composite. The mechanical properties of the composites increase with increasing fiber content, reaching the highest value at 40%, which is 38.79% higher than pure PLA. However, further increases in content lead to fiber agglomeration and decreased composite properties. When the content is relatively low (10%), the mechanical properties are degraded because of internal defects in the material, which is 40.42% lower than pure PLA. Through Micro-CT technology, the fiber was reconstructed, and it was found that the fiber was distributed mainly along the direction of injection molding, and the twin-screw process changes the shape and length of the fiber. By introducing the fiber agglomeration factor function and correcting the Halpin-Tsai criterion, the mechanical properties of composite materials with different contents were successfully predicted. Considering the complex stress state of composite materials in actual service processes, a numerical simulation method was established based on transversely isotropic material using the finite element method combined with theoretical analysis. The mechanical properties of high-content short plant fiber-reinforced composite materials were successfully predicted, and the simulation results showed strong agreement with the experimental results.

Sensitivity of confinement losses in optical fibers to modeling approach.

A prime objective of modeling optical fibers is capturing mode confinement losses correctly. This paper demonstrates that specific modeling choices, especially regarding the outer fiber cladding regions and the placement of the computational boundary, have significant impacts on the calculated mode losses. This sensitivity of the computed mode losses is especially high for microstructure fibers that do not guide light by total internal reflection. Our results illustrate that one can obtain disparate mode confinement loss profiles for the same optical fiber design simply by moving the boundary to a new material region. We conclude with new recommendations for how to better model these losses.

Efficient Fe3C-CF Cathode Catalyst Based on the Formation/Decomposition of Li2-xO2 for Li-O2 Batteries.

Lithium-oxygen batteries have attracted considerable attention in the past several years due to their ultra-high theoretical energy density. However, there are still many serious issues that must be addressed before considering practical applications, including the sluggish oxygen redox kinetics, the limited capacity far from the theoretical value, and the poor cycle stability. This study proposes a surface modification strategy that can enhance the catalytic activity by loading Fe3C particles on carbon fibers, and the microstructure of Fe3C particle-modified carbon fibers is studied by multiple materials characterization methods. Experiments and density functional theory (DFT) calculations show that the discharge products on the Fe3C carbon fiber (Fe3C-CF) cathode are mainly Li2-xO2. Fe3C-CF exhibits high catalytic ability based on its promotion of the formation/decomposition processes of Li2-xO2. Consequently, the well-designed electrode catalyst exhibits a large specific capacity of 17,653.1 mAh g-1 and an excellent cyclability of 263 cycles at a current of 200 mA g-1.

Twisted Silica Few-Mode Hollow GeO2-Doped Ring-Core Microstructured Optical Fiber

This work presents the first instance of a silica few-mode microstructured optical fiber (MOF) being successfully fabricated with a hollow GeO2-doped ring core and by strongly inducing twisting up to 790 revolutions per meter. Some technological issues that occurred during the manufacturing of the GeO2-doped supporting elements for the large hollow cores are also described, which complicated the spinning of the MOFs discussed above. We also provide the results of the tests performed for the pilot samples—designed and manufactured using the untwisted and twisted MOFs described above—which were characterized by an outer diameter of 65 µm, a hollow ring core with an inner diameter of 30.5 µm, under a wall thickness of 1.7 µm, and a refractive index difference of Δn = 0.030. Moreover, their geometrical parameters, basic transmission characteristics, and the measurements of the far-field laser beam profile patterns are also provided.

Mechanical properties and microstructure of engineered cementitious composites with high volume steel slag and GGBFS

Engineered cementitious composites (ECC) achieve exceptional ductility and durability, but the heavy reliance on cement has notable environmental impacts. In this work, the steel slag (SS) and ground granulated blast furnace slag (GGBFS) are introduced into ECC by largely substituting cement. The impact of SS and GGBFS content on ECC’s mechanical performance is analyzed at macro and micro scales in terms of fiber dispersion, mechanical properties, cracking patterns, cement hydration, and microstructure. The results demonstrate that SS can enhance fiber dispersion due to the low water demand and the strong electronic double layer formed on the surface of SS particles. While ECC with a high volume of SS alone (60 wt% SS) lacks the necessary strength for structural applications, the combination of GGBFS and SS exhibits favorable hydration properties and can effectively refine the pore structure. Thus, ECC with GGBFS and SS attains ideal toughness. ASTM C 1018 based toughness indices reveal that the Imax of ECC with 30 wt% GGBFS and 30 wt% SS is 2.30 times that of OPC based ECC. A sustainability analysis demonstrates that substituting 30 wt% SS and 30 wt% GGBFS for cement leads to a 33% reduction in energy consumption and a 53% decrease in CO2 emissions of ECC.

Microstructure, strength, and fiber texture evolutions in arc-based casting using low-carbon steel wire

The present investigation introduced a modified casting route for steel component manufacturing that uses an electric arc to melt the filler wire and transfer the molten metals as tiny droplets into the sand mould. To study the influence of heat input on microstructure, phase percentage, interlamellar spacing, tensile properties, wear resistance, residual stress, and texture fiber evolutions, samples are cast on a wide range of wire feed speed (WFS) (3 to 9 m/min). It has been observed that higher WFS increases the heat input that transfers small-sized molten droplets into the mould cavity at a faster rate and suitably reduces the mould filling time. Heat input shows a positive response with the microstructural evolutions, i.e., large-sized grains with increased pearlite concentration and interlamellar spacing are encountered under high heat input (low cooling rate). It is attributed to improved carbon atom diffusion with the ferrite phase and increased pearlite transformation time. This increment in pearlite concentration and compressive residual stress further enhanced the tensile performances. Wear resistance varies inversely with the heat input rate. A confirmation of the oxide layer formation due to frictional heat generation during wear testing has been authenticated from Raman spectroscopy analysis. Due to its drop-by-drop deposition nature, high WFS raises the heating rate and droplet detachment frequency. Hence, the degree of recrystallisation increases that boost up ϒ-fiber development with intensified θ-fiber components like {001}〈110〉 and {001}〈100〉. Due to the controlled metal transfer under plasma and argon gas shielding, the casted sample has fewer chances of porosity.

Influence of Oxygen Uptake on Pitch Carbon Fiber.

Carbon fiber precursor materials, such as polyacrylonitrile, pitch, and cellulose/rayon, require thermal stabilization to maintain structural integrity during conversion into carbon fiber. Thermal stabilization mitigates undesirable decomposition and liquification of the fibers during the carbonization process. Generally, the thermal stabilization of mesophase pitch consists of the attachment of oxygen-containing functional groups onto the polymeric structure. In this study, the oxidation of mesophase pitch precursor fibers at various weight percentage increases (1, 3.5, 5, 7.5 wt%) and temperatures (260, 280, 290 °C) using in situ differential scanning calorimetry and thermogravimetric analysis isinvestigated. The results areanalyzed to determine the effect of temperature and weight percentage increase on the stabilization process of the fibers, and the fibers aresubsequently carbonized and tested for tensile mechanical performance. Thefindings provide insight into the relationship between stabilization conditions, fiber microstructure, and mechanical properties of the resulting carbon fibers.

Mechanical properties and microstructure of glass fiber reinforced polymer (GFRP) rebars embedded in carbonated reactive MgO-based concrete (RMC)

Reactive MgO cement (RMC) is an emerging low-carbon material which can be a sustainable alternative to ordinary Portland cement (OPC) due to its capability to sequester CO2. However, the application of carbonated RMC concrete in conventional steel reinforced concrete infrastructure is restricted by its inherent low alkalinity (∼10.4), which cannot protect steel from rusting. To address this issue, glass fiber reinforced polymer (GFRP) rebars can be employed. In this study, the mechanical properties and microstructures of RMC-GFRP exposed to various temperatures (23, 40 or 60 °C) for 21, 45 and 90 days were investigated. Experimental results showed that the low-alkalinity carbonated RMC concrete was less aggressive than the normal concrete (NC) to GFRP rebars, remarkably enhancing the tensile strength retention of GFRP rebars from 73.6% to 90.4% after 90 days of exposure at 40 °C. Micromorphology observation indicated that the higher tensile strength retention was ascribed to the reduced GFRP degradation (i.e., matrix cracking, fiber erosion and fiber/matrix interfacial debonding) under the low-alkalinity condition. Additionally, the flexural strength of 90-day aged RMC- and NC-GFRP samples at 60 °C were close to that of unconditioned GFRP samples (791 MPa and 788 MPa vs. 791 MPa), which was attributed to the unchanged glass transition temperature and stable elastic modulus of GFRP. The RMC- and NC-GFRP samples also showed very little change in inter-laminar shear strength as compared to the unconditioned GFRP samples, as the middle layer of GFRP rebars was well-protected from external water and chemicals. Based on the empirical degradation model and activation energy derived from test results at different temperatures, the predicted tensile strength retention of RMC-GFRP after an extended period (∼100 years) under Canadian climate is still sufficient. This study will shed light on the understanding of degradation mechanism and practical application of GFRP reinforced RMC in infrastructure construction.

Recent Advances in MXene-Based Fibers: Fabrication, Performance, and Application.

Two-dimensional transition metal carbide/nitrides (MXenes) have recently received extensive attention due to their diverse material types and versatile structures, large-scale production, and excellent properties. MXene sheets possess abundant hydrophilic functional groups on their surface, which enable them to be assembled into macroscopic fibers or compounded with other functional materials to produce composite fibers. This review aims to provide a comprehensive analysis of MXene fibers in terms of their fabrication, structure, properties, and recent applications as flexible and wearable electronics. The review will discuss the principles of different methods used to synthesize MXene fibers and analyze the characteristics of the as-synthesized fibers, with a particular focus on the wet spinning method. The fundamental relationships between the microstructure of MXene fibers and their resulting mechanical and electrical properties will be explored. Furthermore, the review will elaborate on the progress made in MXene-based fibers in the rapidly growing field of wearable electronics applications, provide insights into future development of MXene fiber materials and propose solutions to the challenges facing practical applications.

Poster 108: The Deep Region of the Supraspinatus Is Architecturally Distinct

Objectives: The supraspinatus (SSP) tendon is the most frequently involved in rotator cuff tears, a common orthopedic condition. Previous anatomical studies have described distinct anterior and posterior regions of the SSP muscle. The purpose of this study is to determine if the deep region of the supraspinatus muscle has significantly different architectural properties from the other regions. This could have implications on the mechanical and functional nature of the deep supraspinatus muscle. Methods: Architecture measurements were collected from 25 cadaver SSPs (Figure 1). There were 13 SSPs without a tear, 3 with partial tears, and 9 with full tears. The anterior to posterior dimension of the humeral head (APHH), musculotendinous junction length (MTJL), muscle mass and length were recorded. The muscle regions were demarcated as deep, [superficial] anterior, and [superficial] posterior. Raw and normalized fiber length, pennation angle, sarcomere length and number were analyzed for each region. Measurements were compared using repeated measures ANOVAs. The intact SSPs were analyzed first, and then a sub-analysis was performed based on presence of tear. Results: In 13 SSPs without tears (Figure 2), the deep region showed a lower mean pennation angle of 3.3±1.0° than the posterior region (11.0±3.9°, p<0.0001), which had a higher angle than the anterior region (7.6±2.6°, p=0.0005). Normalized fiber lengths in the deep region were 21.1% (p=0.0052) and 34.5% (p<0.0001) shorter than posterior and anterior, respectively. Deep region sarcomeres measured 3.4±0.2 µm compared to 3.1±0.2 µm (posterior, p=0.0012) and 3.2±0.2 µm (anterior, p=0.0390). Sarcomere number also decreased in the deep region by 21.2% (p=0.0056) and 34.2% (p<0.0001) compared to posterior and anterior regions, respectively. After including partial (n=3) and full (n=9) tears, all architecture measurements remained different in the deep region versus anterior or posterior. Finally, to help visualize the deep region of the SSP, diffusion tensor imaging with tractography was performed on a healthy volunteer’s MRI (Figure 3) to depict the tissue microstructure and muscle fiber orientation/length. Conclusions: The deep supraspinatus has lower pennation angles, shorter fiber lengths, and fewer but longer sarcomeres. These structural differences suggest a functionally unique ‘submuscle’ within the supraspinatus.

Tuning of the Brillouin scattering properties in microstructured optical fibers by liquid infiltration

We demonstrate the possibility to modify the Brillouin scattering properties of a microstructured pure-silica core optical fiber, by infiltrating a liquid inside its holes. In particular, we show that the dependence of the Brillouin frequency shift (BFS) on the temperature can be reduced by infiltration, owing to the large negative thermo-optic coefficient of the liquid. Infiltrating a chloroform-acetonitrile mixture with a refractive index of 1.365 inside the holes of a suspended-core fiber with a core diameter of 3 µm, the BFS temperature sensing coefficient is reduced by ≈ 21%, while the strain sensitivity remains almost unaltered. Besides tuning the temperature sensing coefficient, the proposed platform could find other applications in Brillouin sensing, such as distributed electrical and magnetic measurements, or enhanced Brillouin gain in fibers infiltrated with high nonlinear optical media.

Preparation of cellulose nanofibrils and their effects on the rheological properties and compressive strength of oil-well cement paste

In this study, an efficient hybrid preparation method was developed for isolating cellulose nanofibrils (CNFs) from cellulose fibres using ball milling and tetramethylpiperidine-1-oxyl (TEMPO) oxidation. The chemical structure and microstructure of the obtained CNFs were characterised using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Additionally, the effects of CNFs on the rheological properties, thickening time, and compressive strength of oil-well cement paste were investigated. Ball milling for 30 min at a revolution speed of 500 r/min changed the microstructure of the cellulose fibres to a ‘fibrous-sheet structure’, reduced their diameters to several micrometres, and increased their specific surface area. Furthermore, this change in the cellulose fibre microstructure reduced the TEMPO oxidation reaction time, thereby improving the preparation efficiency of the CNFs. The TEM and XPS results indicate that CNFs can be obtained via TEMPO oxidation for 2 h. The surface of the CNFs contained up to 5.08% C = O groups. Additionally, compared to the pure oil-well cement sample, the yield stress of the oil-well cement paste containing 0.2% CNFs increased from 2.31 Pa to 9.84 Pa, and its consistency increased from 10.6 Bc to 28.0 Bc, which confirmed that the CNFs formed a ‘fabric structure’ to increase the structural force of the oil-well cement. Moreover, the compressive strength of the oil-well cement paste containing 0.2% CNFs cured for 2 d at 60 °C increased by 50.4%, while that of the paste cured for 14 d increased by 53.0% compared to that of the pure oil-well cement paste. These achievements can provide some sight for designing the high-performance oil-well cement paste.

Manipulating mechanical properties of CaTiO3:Eu3+ flexible fiber membrane by fiber design

AbstractFlexible inorganic functional materials have received extensive attention in recent years due to their unique properties and potential application prospects. Among various flexible materials, ceramic fiber membranes have great application prospects due to their functional original structure. Unlike other materials, such as one‐dimensional flexible ice, two‐dimensional BaTiO3, and three‐dimensional α‐Ag2S, ceramic fiber membranes are high‐performance materials with a functional unit structure. In the field of electrospinning, electrospinning technology can effectively control the microstructure of ceramic fibers, allowing for multileveled structure design, such as ordered electrospinning technology and disordered electrospinning technology, which can effectively control the functional primitive structure. However, the mechanical behavior of these structures is still poorly understood. In this groundbreaking study, we investigated the functional original structure of CaTiO3:Eu3+ electrospinning fiber membranes from the bottom‐up and explored the effect of grain diameter ratio on mechanical behavior and studied the effect of Eu3+ ions on the luminescent properties of CaTiO3 functional fiber membranes. By controlling the electrospinning parameters and avoiding inherent mechanical property differences between the microcrystals, we realized the stress concentration design from the perspective of functional element structure. Our results show that the stress concentration design at the bottom of the multileveled structure significantly affects the overall mechanical behavior. This work proposes a new method to control the mechanical properties of inorganic functional ceramic fiber membranes through functional element structure design and provides the first bottom‐ordered regulation method, offering a new dimension for future research in this field.

Excellent hydration properties and oil holding capacity of citrus fiber: Effects of component variation and microstructure

In this study, the effects of components and microstructure on the water holding capacity (WHC), water swelling capacity (WSC), and oil holding capacity (OHC) of citrus fiber were investigated. Nine citrus fiber samples with various component percentages were prepared by an efficient fiber component separation process. The chemical composition, FT-IR, XRD, TG, WHC, WSC, OHC, particle size distribution, and zeta potential of all samples were determined. It was revealed that citrus fiber samples decreased in particle size and zeta potential, increased in crystallinity, and gradually decreased or even disappeared in the characteristic absorption peaks of hydroxyl groups, lignin, hemicellulose, and pectin with increasing treatment steps, which was consistent with chemical composition. Thermal stability analysis showed that citrus fiber with cellulose as the main component had higher thermal stability. The cellulose and hemicellulose components increased WHC by up to 75.99%, and the cellulose component increased OHC by up to 20.61%. According to SEM and Pearson correlation analysis, WHC and WSC were determined by hemicellulose and cellulose, as well as the microstructure of citrus fiber, while OHC was mainly depended on cellulose and microstructure. It was concluded that the loose and large interstitial structure was the basis for the strong water or oil absorption properties, and the more complete primary wall structure was the prerequisite guarantee of the strong water or oil locking ability.

In Situ DNA Detection Using a Phase-Demodulated High-Order Intermodal Interferometer Based on an Exposed-Core Microstructure Fiber

In this paper, we demonstrate a phase-demodulated high-order intermodal interference based on exposed-core microstructure fiber (ECF), and it is applied for low concentration in-situ deafness gene DNA detection. The simulation results show that the phase sensitivity of the high-order interference mode (LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> -LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21a</sub> ) is about 6 times higher than that of the low-order (LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> -LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11b</sub> ), which is different from the traditional wavelength coded demodulation method. Hybridization experiments of complementary and non-complementary deafness gene DNA fragments were carried out, and the sensing system was obtained to screen for complementary gene fragments. DNA complementary fragments with concentrations as low as 1 nM can be detected with a corresponding phase variation of 7.32 °. The limit of detection is as low as 0.089 nM. The experiment and theoretical analysis prove that this fiber optic biosensor can obtain high sensitivity and signal-to-noise ratio with phase-demodulation high-order intermodal interference scheme, which provides an alternative for the subsequent studies of high sensitivity and high precision sensors.

Experimental investigation on the impact properties and microstructure of recycled steel fiber and silica fume reinforced recycled aggregate concrete

With the continuous development of the economy and society, the production of solid waste is increasing. Construction and demolition waste (CDW), used tires and silica fume are the main components of solid waste. Recycling these materials will reduce resource pressure, decrease carbon emissions and protect the environment, while bringing certain economic benefits. This study focused on the influence of the synergistic effect of recycled steel fibers (RSF) and silica fume on the mechanical properties and impact resistance of recycled aggregate concrete (RAC). The mathematical statistical model of Weibull distribution was adopted to depict the impact results. In addition, the microstructure of the interfacial transition zone (ITZ) between the cement paste and the aggregate/fiber was researched by scanning electron microscopy (SEM). Results revealed that the synergistic effect of RSF and silica fume significantly improved the impact resistance of RAC. Especially the specimen containing 10% silica fume and 0.75% RSF performed the best properties, the first crack impact and failure impact energy increased by 421.9% and 461.3%, the net-gain in them by the synergistic action of silica fume and RSF with values of 102.7% and 115.3%. The distribution law of the impact life for RSF reinforced RAC can better describe by the two-parameter Weibull distribution function. Impact resistance life was predicted corresponding to reliability levels. SEM investigations revealed that the ITZ between cement and aggregate/RSF significantly improved by mixing silica fume.

Multi working mode SPR chip laboratory for high refractive index detection.

The Fiber SPR chip laboratory has become a popular choice in biochemical detection. To meet the needs of different kinds of analytes for the detection range and number of channels of the chip, we proposed a multi-mode SPR chip laboratory based on microstructure fiber in this paper. The chip laboratory was integrated with microfluidic devices made from PDMS and detection units made of bias three-core fiber and dumbbell fiber. By injecting light into different cores of a bias three-core fiber, different detection areas of dumbbell fiber can be selected, enabling the chip laboratory to enter high refractive index detection, multi-channel detection and other working modes. In the high refractive index detection mode, the chip can detect liquid samples with a refractive index range of 1.571-1.595. In multi-channel detection mode, the chip can achieve dual parameter detection of glucose and GHK-Cu, with sensitivities of 4.16 nm/(mg/mL) and 9.729 nm/(mg/mL), respectively. Additionally, the chip can switch to temperature compensation mode. The proposed multi working mode SPR chip laboratory, based on micro structured fiber, offers a new approach for the development of portable testing equipment that can detect multiple analytes and meet multiple requirements.

Experimental Study on Mechanical Performance and Microstructure of Polypropylene Fiber Recycled Concrete

Recycled concrete reinforced by polypropylene fibers boosts an alternative sustainable solution to address the need of reusing waste concrete. This paper reports experimental and analytical studies of static and dynamic comprehensive behavior on recycled concrete specimens reinforced with different contents of polypropylene fiber (PPF). Electro-hydraulic pressure testing was used to obtain static compressive strength, whereas 74 mm diameter Split Hopkinson Pressure Bar (SHPB) was applied for dynamic impact compression tests at four strain rates. In addition, the reinforcing mechanism of polypropylene fiber on recycled concrete was analyzed of the micro-structure through Scanning Electron Microscope (SEM). Finally, ANSYS/LS-DYNA was applied for the simulation of the SHPB test, which was validated by good agreements of the stress waveform and failure modes of the fiber-reinforced recycled concrete specimen during the impact test. It appears that polypropylene fiber can optimize the microscopic pore structure inside the concrete, thus effectively improving the mechanical properties of recycled concrete which were originally defected by recycled aggregate. Also, higher strain rates significantly increase dynamic compressive strength as well as impact toughness. This study shows that the optimal content of polypropylene fiber in recycled concrete is 0.1% – 0.2%. The numerical simulation by ANSYS/LS-DYNA further proved that the HOLMQUIST-JOHNSON-COOK (HJC) constitutive model can better reflect the dynamic performance of concrete.