Discontinuous Fiber Research Articles

Biomimetic, fire-resistant, ultralight and porous carbon fiber sponges enabling safe and efficient remediation of crude oil spills in harsh environments

Advanced absorbents must meet the requirements of superior hydrophobic/oleophilic behavior, favorable adsorption efficiency, and high photothermal and Joule heating performance to handle frequent crude oil spills. However, current carbon-based absorbents suffer from poor fire resistance, thus severely limiting their application in harsh environments. Herein, inspired by a bird's nest, a polymer “welding” strategy is proposed to design a versatile absorbent in which the polymer serves as a “binder” to interconnect discontinuous fibers together to form a 3D welded structure. The continuous conductive networks endow the absorbent with high photothermal and Joule heating effect, thus achieving all-weather adsorption, and improving the adsorption efficiency of crude oil via the self-heating function. Compared with other absorbents, the absorbent prepared via polymer welding technology exhibited preferable comprehensive performance, such as superhydrophobicity, high fire resistance, and high absorption efficiency. Specially, the noninflammable absorbent can restrain the combustion of crude oil, thereby reducing its combustion in case of fire. The versatile absorbent is expected to provide a promising solution for the safe and efficient cleanup of crude oil spills in harsh environments. Overall, the unique polymer welding strategy can be developed into a universal strategy for other material systems to expand their applications.

Engineered cementitious composites - a review

Engineered Cementitious Composites (ECC) is also known as bendable concrete, characterized by tight crack width control. As we know the concrete is brittle in nature, expected to fail catastrophically. To minimize the damages caused by the concrete failure in seismic region we go for special detailing to enhance the ductility nature of concrete members, which leads to a complicated design. To overcome this problem a new type of composites are designed called Engineered Cementitious Composites based on a combination of structural engineering and micromechanics. This paper deals with the literature survey on micromechanics design to achieve the pseudo strain hardening behaviour, i.e. to achieve two criteria’s namely i) Strength Criteria ii) Energy criteria. Both Reinforced Concrete and Fiber Reinforced Concrete shows strain softening behaviour after the appearance of the first crack whereas the ECC shows strain hardening behaviour after the appearance of first crack because of the presence of randomly oriented discontinuous fibers. Regarding Strength criteria, Fiber bridging stress plays a major role and for energy criteria, Matrix toughness plays a major part. By tailoring these two parameters, strain hardening behaviour of the composite can be achieved. Apart from these two parameters mixing of fresh ECC is also an important factor to be considered, since uniform dispersion of fibers leads to bridging of the cracks which makes the composite to have a multiple fine cracks before failure instead of having a big single crack.

Investigation on Stress Relaxation of Discontinuous Recycled Carbon Fiber Composites

Investigation on Stress Relaxation of Discontinuous Recycled Carbon Fiber Composites

The Influence of Fibre Cross Section Shape and Fibre Surface Roughness on Composite Micromechanics

Many of the carbon and natural fibres used in composite reinforcement have a non-circular cross section. Recently non-circular, or flat, cross section glass fibre products have become commercially available. This paper explores the potential effects that such non-circular fibre cross section shapes may have on the micromechanics of stress transfer at the composite fibre–matrix interface and the resulting changes in composite strength performance. Analytical modelling is used to show how the critical fibre length in composites with non-circular fibres is always less when compared to circular fibres with an equal cross-sectional area. This can result in significant changes to the strength performance of discontinuous fibre reinforced composites. Additionally, it is shown that the surface roughness found on natural and carbon fibres, many of which are also non-circular in cross section, can decrease the critical fibre length still further. These effects have important consequences for the use of single fibre micromechanical tests used for the characterisation of interfacial strength.

Fatigue Resistance of Dissected Lower First Molars Restored with Direct Fiber-Reinforced Bridges—An In Vitro Pilot Study

The aim of this research was to evaluate the mechanical impact of utilizing different fiber-reinforced composite (FRC) systems to reinforce inlay-retained bridges in dissected lower molars with different levels of periodontal support. A total of 24 lower first molars and 24 lower second premolars were included in this study. The distal canal of all molars received endodontic treatment. After root canal treatment, the teeth were dissected, and only the distal halves were kept. Standardized class II occluso-distal (OD) (premolars) and mesio-occlusal (MO) (dissected molars) cavities were prepared in all teeth, and premolar-molar units were created. The units were randomly distributed among four groups (n = six/group). With the aid of a transparent silicone index, direct inlay-retained composite bridges were fabricated. In Groups 1 and 2, both discontinuous (everX Flow) and continuous (everStick C&B) fibers were used for reinforcement, while in Groups 3 and 4, only discontinuous fibers (everX Flow) were used. The restored units were embedded in methacrylate resin, simulating either physiological periodontal conditions or furcation involvement. Subsequently, all units underwent fatigue survival testing in a cyclic loading machine until fracture, or a total of 40,000 cycles. Kaplan-Meyer survival analyses were conducted, followed by pairwise log-rank post hoc comparisons. Fracture patterns were evaluated visually and with scanning electron microscopy. In terms of survival, Group 2 performed significantly better than Groups 3 and 4 (p < 0.05), while there was no significant difference between the other groups. In the case of impaired periodontal support, a combination of both continuous and discontinuous short FRC systems increased the fatigue resistance of direct inlay-retained composite bridges compared to bridges that only contained short fibers. Such a difference was not found in the case of sound periodontal support between the two different bridges.

Flat glass fibres: The influence of fibre cross section shape on composite micromechanics and composite strength

Many of the fibres used in composite reinforcement have a non-circular cross section and recently non-circular glass fibre products have become commercially available. This paper explores the potential effects that such non-circular fibre shapes may have on the micro-mechanics of stress transfer at the fibre–matrix interface and the resulting changes in composite strength performance. Analytical modelling is used to show how the critical fibre length in composites with non-circular fibres is always less when compared to circular fibres with an equal cross sectional area. This can result in significant changes to the strength performance of discontinuous fibre reinforced composites. Additionally it is shown that non-circularity in fibre cross section can have important consequences for the use of single fibre micromechanical tests in the characterisation of interfacial strength.

Study on Strength and Durability Properties of Polypropylene and Carbon Fiber Reinforced Concrete Composite

Abstract: Concrete is the most widely utilized “manmade” material globally for construction in many developing countries in all types of civil engineering works. Also, concrete is an environmental - friendly material and in areas of growing environment – related awareness that is of prime importance. The weakness of concrete is due to the presence of micro cracks at mortar aggregate interface. To overcome the existing problems addition of fibers in the concrete has been come in to practice. In fiber reinforced concrete the fibers are added to the concrete mix so that those are discontinuous fibers will be uniformly distributed in the mix and improve the concrete properties in all directions. In this research paper, an attempt is made to use fibers only .The experimental investigation consisting of casting and testing of compression tests were conducted on 150x150x150mm cube and 150mmx300mm, cylindrical specimens using test method that gave the complete compressive strength, split tensile test using with and without fiber.The strength and durability properties are carried out for various mix designations and compared with normal conventional concreteIn present project work M25 grade considered and the polypropylene (PP) fiber at 0.5,1 ,1.5 ,2 and 2.5% volume fractions and carbon fibers at 1, 1.5, 2,2.5 and 3% volume fractions are introduced into fiber‐reinforced. Based on the results will find the superior crack resistance, improved tensile strength. The proposed sample will be tested at 7 days, 21 days and 218days age of curing. These results will show whether the FRC is suitable for proper confinement or not for structures subject to extreme load conditions

Reuse of Carbon Fibers and a Mechanically Recycled CFRP as Rod-like Fillers for New Composites: Optimization and Process Development

The rising amount of carbon fiber reinforced polymer (CFRP) composite waste requires new processes for reintroducing waste into the production cycle. In the present research, the objective is the design and study of a reuse process for carbon fibers and CFRP by mechanical recycling consisting of length and width reduction, obtaining rods and reintegrating them as fillers into a polymeric matrix. Preliminary studies are carried out with continuous and discontinuous unidirectional fibers of various lengths. The processing conditions are then optimized, including the length of the reinforcement, the need for a plasma surface treatment and/or for resin post-curing. The resin is thermally characterized by differential scanning calorimetry (DSC), while the composites are mechanically characterized by tensile strength tests, completed by a factorial design. In addition, the composites tested are observed by scanning electron microscopy (SEM) to study the fracture mechanics. Optimal processing conditions have been found to reduce the reinforcement length to 40 mm while maintaining the mechanical properties of continuous reinforcement. Furthermore, the post-curing of the epoxy resin used as matrix is required, but a low-pressure plasma treatment (LPPT) is not recommended on the reinforcement.

Fracture behavior of discontinuous fiber-reinforced composite inlay-retained fixed partial denture before and after fatigue aging.

To evaluate the fracture behavior of inlay-retained fixed partial dentures (IRFPDs) made of experimental short fiber-reinforced composite (SFRC) computer-aided design/computer-aided manufacturing (CAD/CAM) block before and after cyclic fatigue aging. Five groups (n=20/group) of three-unit posterior IRFPDs were fabricated. The first and second groups were CAD/CAM fabricated from experimental SFRC blocks or lithium-disilicate (IPS e.max CAD, IVOCLAR) materials, the third group comprised a three-dimensional-printed composite (Temp PRINT, GC), and the fourth and fifth groups comprised conventional laboratory flowable composite (Gradia Plus, GC) and commercial flowable SFRC (everX Flow, GC), respectively. All IRFPDs were luted into a metal jig with adhesive dual-cure resin cement (RelyX Ultimate, 3M ESPE). Half the IRFPDs per group (n=10) were subjected to fatigue aging for 10,000 cycles. The remaining half were statically loaded until fracture without fatigue aging. The load was applied vertically between triangular ridges of the buccal and lingual cusps. The fracture mode was visually examined using optical and scanning electron microscopy (SEM). Data were statistically analyzed using a two-way analysis of variance (ANOVA) followed by Tukey's HSD test. ANOVA revealed that IRFPDs made of experimental SFRC CAD/CAM had the highest (P<0.05) load-bearing capacity before (2624±463 N) and after (2775±297 N) aging among all groups. Cyclic fatigue aging decreased the load-bearing capacity (P>0.05) of all tested prostheses, except for the experimental SFRC CAD/CAM and conventional laboratory composite IRFPDs (P>0.05). SEM images showed the ability of discontinuous short fibers in the experimental SFRC CAD/CAM composite to redirect and hinder crack propagation. CAD/CAM-fabricated IRFPDs made of experimental SFRC blocks showed promising performance in clinical testing in terms of fracture behavior.

Identification of hybridization strategies for combining fused filament fabrication with unidirectional tape reinforcement

Additive manufacturing processes such as fused filament fabrication (FFF) enable highly individualized production with thermoplastics, can thus produce load-path-optimized components and therefore lightweight structures. Since the mechanical properties of FFF are lower than those of traditional processes, discontinuous and continuous fibers are used to improve the mechanical properties. Currently the reinforcement effect of continuous fibers cannot be fully utilized in FFF due to the lack of impregnation of the fibers and only low processing pressures during hybridization. To tackle this challenge, four strategies for hybridization of pre-impregnated unidirectional (UD) carbon fiber tapes with polyamide 6 (PA6) matrix and FFF-printed parts are investigated in this work. The strategies differ in the timing of the application of consolidation steps, i.e. a controlled application of heat and pressure in the interface between FFF-layers and UD-tape. With the use of mechanical pull-out tests, the maximum achievable shear stresses of the interface are investigated. Additional computed tomography (CT) scans of the interfaces allow the four hybridization strategies to be evaluated. It is shown that even a single consolidation in the right process step significantly increases the adhesion between UD-tape and FFF layer leading to about 100–200% increased shear stresses before delamination occurs. To ensure the transferability of the hybridization strategies to other material systems and to validate the results, filaments of pure PA6 as well as PA6 with short glass and carbon fibers were used for the FFF process.

Role of discontinuous fiber core material on the mechanical behavior of hybrid sandwich polyester composites

This study investigated the potential for improving the mechanical behavior of glass fiber polyester composites by using symmetric hybrid sandwich configurations that combine continuous woven composite and different discontinuous reinforcements used as a core. The discontinuous reinforcements included sheet molding compound (SMC), bulk molding compound (BMC), and the discontinuous prepreg based platelets that were chopped from the woven trim scrap. Hybrid sandwich configurations using different core materials exhibited improvements in flexural mechanical properties, while providing more progressive failure under both flexural and compressive loading. Compressive strength in polyester SMC and woven laminate was significantly lower than flexural strength, while BMC and chopped platelets exhibited similar levels of strength in flexure and compression. Overall, hybridized compression molding produced sandwich structures can be used to control the failure progression and to improve the structural characteristics of composite, especially under flexural loads. The trim scrap core sandwich configuration had mechanical properties comparable with the BMC core hybrid. Therefore, trim scrap upcycling can be an efficient approach to reducing the amount of material waste during the manufacturing.

Open Hole Tension of 3D Printed Aligned Discontinuous Composites

This paper explores the use of Discontinuous Aligned Fibre Filament (DcAFF), a novel discontinuous fibre reinforced thermoplastic filament for 3D printing, to produce structural complex parts. Compared to conventional composite manufacturing, 3D printing has great potential in steering fibres around small structural features. In this current study, the initial thin carbon fibre (CF)-poly(L-lactic acid) (PLA) tape, produced with the High Performance Discontinuous Fibre (HiPerDiF) technology, is now reshaped into a circular cross-section filament, the DcAFF, using a bespoke machine designed to be scalable to high production rates rather than using a labour-intensive manual moulding method as in previous work. The filaments are then fed to a general-purpose 3D printer. Tensile and open-hole tensile tests were considered in this paper for mechanical and processability of DcAFF. The 3D printed specimens fabricated with the DcAFF show superior tensile properties compared to other PLA-based 3D printed composites, even those containing continuous fibres. Curvilinear open-hole tensile test samples were fabricated to explore the processability and performances of such material in complex shapes. The mechanical performance of the produced specimens was benchmarked against conventionally laid-up specimens with a cut hole. Although the steered specimens produced have lower strength than the fully consolidated samples, the raster generated by the printing path has turned the failure mechanism of the composite from brittle to ductile.

Influence of fiber breakage on flow behavior in fiber length- and orientation-dependent injection molding simulations

• Orientation dependent fiber breakage modeling approach • Fiber length and orientation dependent flow modeling • Coupling of transient fiber breakage modeling and fiber dependent viscosity and flow modeling Injection molding is one of the most important processes for manufacturing discontinuous fiber reinforced polymers (FRPs). The matrix of FRPs shows a transient chemo-thermomechanical behavior and the fibers create anisotropy influencing physical properties. Hence, FRPs are complex materials, but also likely used in volume production. In this work, the fiber-induced anisotropic behavior during mold filling is modelled with an anisotropic fourth order viscosity tensor. The viscosity tensor takes second and fourth order fiber orientation tensor, fiber length and non-Newtonian matrix viscosity into account. In this way, the macroscopic simulation captures the influence of the flow field on the fiber re-orientation and vice versa. The fiber orientation tensor is used to determine reference fibers in every element for calculation of hydrodynamic forces. This information is used in a novel fiber breakage model, based on buckling of fibers in Jeffery's orbit. The result is a macroscopic molding simulation with not only transient fiber orientation distribution, but also fiber length distribution. Due to the anisotropic viscosity tensor, the predicted fiber breakage influences the material's viscosity and flow behavior, which is also visible in the simulated cavity pressure. The results are validated with injection molding experiments, performed with a glass fiber reinforced phenolic compound, showing good agreement.

Quality Analysis of Weld-Line Defects in Carbon Fibre Reinforced Sheet Moulding Compounds by Automated Eddy Current Scanning

Discontinuous fibre reinforced composites enable the manufacture of integrated structural components via the complex flow process of compression moulding. However, such processes can lead to the formation of detrimental weld-lines. Here, the meso-structure of carbon fibre sheet moulding compounds (C-SMC) was analysed using conventional non-destructive techniques and automated eddy current (EC) scanning, as well as destructive methods, in an attempt to identify defects such as weld-lines in this class of materials. Compression-moulded plaques with forced weld-lines in two different configurations (adjacent and opposing flow joints) were analysed, showing up to 80% strength reduction versus a defect-free plaque. The EC-determined local fibre orientation and elucidated local microstructure matched those obtained using conventional techniques, showing a dramatic fibre tow alignment parallel to the weld-lines. It was found that failure occurred in proximity to the “non-uniformity” defect regions identified by EC analyses, demonstrating the use of robot-guided EC for successful defect detection in C-SMC structures.

Mechanical properties of composites manufactured from low twist hybrid yarns made of discontinuous carbon and polyamide 6 fibres

Composites based on e.g. randomly oriented nonwovens and injection moulded structures from discontinuous carbon fibre (CF), which are processed industrially exhibit low tensile strengths of 200–300 MPa and 400 MPa, respectively. In contrast, composites based on twisted hybrid yarns from discontinuous CF and thermoplastic fibre show higher tensile strengths such as 1150 MPa. Reasons are improved fibre orientation and higher fibre volume content. However, tensile strength is still lower than that of uni-directional carbon fibre reinforced composites (CFRP) based on continuous filament yarn, which is around 1560 MPa. The reason is a low fibre orientation due to yarn twisting and high fibre shortening, which occurs throughout the yarn manufacturing process. As mechanical properties of composites largely depend on fibre orientation and length, there is a high potential to achieve higher mechanical properties in CFRP by ensuring gentle processing of CF and reducing yarn twist. However, due to brittleness and smooth surface of CF, spinning of yarns with low twist (&lt;60 T/m (twist per meter)) is challenging. In order to exhaust the potential of hybrid yarns, a semi-industrial process chain to produce hybrid yarns while ensuring gentle processing of discontinuous CF (fibre length 100 mm) and polyamide 6 fibres (fibre length 80 mm) at significantly low level of twist 20 T/m is reported in this paper. Carbon fibre reinforced composite manufactured from these hybrid yarns show high tensile strength (1453 ± 27 MPa), Young’s modulus (94 ± 6 GPa), flexural strength (1090 ± 41 MPa) and flexural modulus (98 ± 5 GPa).

3D-Printed Fiber-Reinforced Polymer Composites by Fused Deposition Modelling (FDM): Fiber Length and Fiber Implementation Techniques.

Fused Deposition Modelling (FDM) is an actively growing additive manufacturing (AM) technology due to its ability to produce complex shapes in a short time. AM, also known as 3-dimensional printing (3DP), creates the desired shape by adding material, preferably by layering contoured layers on top of each other. The need for low cost, design flexibility and automated manufacturing processes in industry has triggered the development of FDM. However, the mechanical properties of FDM printed parts are still weaker compared to conventionally manufactured products. Numerous studies and research have already been carried out to improve the mechanical properties of FDM printed parts. Reinforce polymer matrix with fiber is one of the possible solutions. Furthermore, reinforcement can enhance the thermal and electrical properties of FDM printed parts. Various types of fibers and manufacturing methods can be adopted to reinforce the polymer matrix for different desired outcomes. This review emphasizes the fiber types and fiber insertion techniques of FDM 3D printed fiber reinforcement polymer composites. A brief overview of fused deposition modelling, polymer sintering and voids formation during FDM printing is provided, followed by the basis of fiber reinforced polymer composites, type of fibers (synthetic fibers vs. natural fibers, continuous vs. discontinuous fiber) and the composites' performance. In addition, three different manufacturing methods of fiber reinforced thermoplastics based on the timing and location of embedding the fibers, namely 'embedding before the printing process (M1)', 'embedding in the nozzle (M2)', and 'embedding on the component (M3)', are also briefly reviewed. The performance of the composites produced by three different methods were then discussed.

Thermophysical Properties Mapping of Composites by Lock-in Thermography: Applications on Carbon Fiber Reinforced Plastics

We propose a versatile method for measuring the thermophysical properties of composites by means of lock-in thermography (LIT) technique. The method is based on analyzing the thermal response distribution induced by periodic laser heating, which enables simultaneous high-spatial-resolution mapping of the effective out-of-plane thermal diffusivity, thermal conductivity, and volumetric heat capacity over the surface of the material. We validate the method using a reference material and demonstrate its capability in visualizing the effective properties of laminated carbon fiber reinforced plastic and carbon fiber reinforced thermoplastic with discontinuous fibers. The results showed that the LIT-based approach has high reproducibility and sensitivity, which allows observing the effect of fiber orientations on the effective properties. The proposed method will be useful for thermal research in composites, defect detection, and for investigating component geometric arrangement effects on the thermophysical properties.

Additive manufacturing of high density carbon fibre reinforced polymer composites

Additive manufacturing (AM) of carbon fibre reinforced thermoplastic composites can offer advantages over traditional carbon fibre manufacturing through improved design freedom and reduction in production time and cost. However, the carbon fibre composites produced using current state-of-the-art AM approaches generally possess high porosity (18–25 %) compared to those produced by conventional manufacturing (1 %). An approach known as composite fibre additive manufacturing (CFAM) is presented, involving selectively printing a binder and polymer powder onto discontinuous carbon fibre sheets, which are then compressed, heated and post-processed to form net shape components. The results demonstrate a correlation between compaction pressure applied and porosity/fibre volume fraction within components. Composite components were produced containing porosity of 1.5 % and fibre volume content of 15 % with 97 MPa tensile strength and 8.9 GPa elastic modulus, presenting a new approach for production of discontinuous carbon fibre reinforced polymer parts with mechanical properties exceeding those of state-of-the-art AM.

Estimation of the fiber orientation distribution of carbon fiber–reinforced plastics using small-angle X-ray scattering

• Carbon fiber orientation distributions in the CFRP were determined using their SAXS analysis. • Fast evaluation was achieved by introducing a calibration curve for integral width of the azimuthal direction. • Similar orientation distribution compared those obtained with X-ray CT could be obtained. The orientation of discontinuous carbon fibers (CFs) in CF-reinforced plastics (CFRPs) determines their properties, necessitating convenient evaluation methods. Herein, a fast and non-destructive method is proposed for the evaluation of the orientation distribution of CFs in CFRPs based on small-angle X-ray scattering (SAXS). The width of the equatorial streak in the SAXS pattern of (or azimuthal intensity distribution of scattering from) a CFRP depends on the orientation distribution of its CFs; a calibration curve for this relationship was derived by assuming the orientation distribution to be Gaussian. This calibration curve was used to determine the orientation distributions of CFRPs featuring CFs with different orientation distributions, which correspond well with the orientation distributions determined by X-ray computed tomography. Thus, the proposed method can be used to conveniently and quantitatively evaluate the orientation distribution of discontinuous CFs in CFRPs. Because this method is based on scattering from elongated nanovoids in CFs, it can be used to evaluate composite materials in which reinforcing fibers containing elongated scattering bodies, e.g., high-strength organic fibers containing fibrils, are preferentially oriented.

Optimization of mixture parameter for physical and mechanical properties of reactive powder concrete under external sulfate attack using Taguchi method

• Taguchi analysis has been used to determine optimum mix design parapeter of RPC exposed to different Na 2 SO 4 solutions and exposure conditions. • Optimized level for RPC mixture with different water to binder ratio, steel fiber contents, and silica fume contents depends on different external sulfate attack exposure conditions. • RPC appears to be sustainable and durable material under different external sulfate attack exposure conditions. Reactive powder concrete (RPC) is defined as a cementitious composite material with an optimized size of granular constituents, very low water-to-binder ratio (w/b), pozzolanic materials like silica fume (SF), and discontinuous fiber reinforcement. RPC applications include bridge decks and girders, seismic columns, wind turbine towers, and pile foundations. Especially, a durable and robust RPC pile foundation with long service life is essential in building construction because continuous maintenance is impossible. Moreover, natural in-situ conditions such as water table, temperature, and sulfate concentration in soil to which the pile foundation is exposed are critical and related to deteriorating the pile foundation. Therefore, the Taguchi design of experiments (DOE) was used in this research to determine the optimal RPC mixture with beneficial characteristics against external sulfate attack (ESA). Mixture design parameters included steel fiber content (0, 1 and 2 %), w/b (0.16, 20 and 0.24), and SF content (15, 20 and 25 %). In contrast, environmental conditions of ESA exposure contained three different sodium sulfate (Na 2 SO 4 ) concentrations (0.35, 1.05, and 3.15 M), cyclic and continuous exposure at normal temperature (20 °C), and continuous exposure at elevated temperatures (40 °C and 60 °C). The analytical and statistical investigation evaluated mass change, compressive strength, and modulus of rupture in RPC mixtures exposed to these conditions for 52 weeks. Test results show that cyclic exposure and increased solution temperature in ESA facilitate RPC damage. If measured after air drying, RPC mixtures subjected to cyclic ESA are especially susceptible to failure. Taguchi analysis indicated the optimum parameters’ level for mass change as: 0 % steel fiber, w/b = 0.16, and 20 % SF content; for the compressive strength: 2 % steel fiber, w/b = 0.24, and 20 % SF content; and, for modulus of rupture: 2 % steel fiber, w/b = 0.20, and 25 % SF content. In conclusion, RPC appears to be sustainable and durable material under different ESA exposure conditions.