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This study aims to experimentally investigate the impact resistance of Textile Reinforced Concrete (TRC) panels under high-velocity impact loading. 54 control and TRC panels were fabricated using a standard (29 MPa) and a high (101 MPa) compressive strength concrete, as well as Ultra-High-Performance Fibre Reinforced Cementitious Composites (UHPFRCCs) (132 MPa). 36 out of 54 TRC panels were reinforced with carbon and glass textiles. The mechanical properties of all types of composite systems were investigated under four-point bending test. All specimens were subjected to a high-velocity impact load from a hemispherical steel projectile travelling with an initial impact velocity ranging from ∼60 m.s−1 to ∼160 m.s−1. A high-speed camera was used to track the projectile and record the impact process. The level of impact damage to the TRC panels was quantified by the mass loss, penetration depth and scabbing diameter. The results demonstrated that the standard compressive strength concrete had a flexural toughness 17 % higher than that of the higher compressive strength. The most efficient system in reducing crack propagation and local damage against high-velocity (160 m.s−1) projectile impact load was the UHPFRCCs reinforced with carbon textiles, resulting in maximum penetration depth 25 % lower compared to unreinforced UHPFRCCs panels. • We investigate the impact resistance of Textile Reinforced Concrete (TRC) panels. • We investigate the effect of concrete strength and type of textile on impact resistance. • The UHPFRCCs reinforced with carbon textiles were the most effective against high-velocity impact. • Existing empirical formulas for predicting penetration depth were found to be insufficient for samples with reinforcement. [ABSTRACT FROM AUTHOR]

Textile Reinforced Cement (TRC) composites are widely investigated as a slender alternative to steel-reinforced concrete. Most existing studies focus on glass or carbon fibres as reinforcement. Literature on the flexural behaviour of basalt TRC, and more specifically on the coating of basalt fibres, remains sparse. The present study investigates the flexural behaviour of TRC reinforced by two-dimensional woven basalt textiles. The experimental program focuses on the impact of the reinforcement volume fraction and the coating. First, the mechanical behaviour of basalt fibres was characterised by tensile tests, while the bond with the mortar matrix was investigated by pullout tests. Next, four TRC configurations with varying reinforcement volume fraction and coating were tested under four-point bending. Epoxy impregnation increased the tensile strength of basalt yarns twofold and triggered pullout behaviour from the cement matrix. Using higher reinforcement volume fraction and coating in TRC significantly improved the flexural behaviour, i.e. more than doubled the post-cracking stiffness and the failure load. Also, the number of flexural cracks increased while their opening remained smaller (below 120 µm up to a displacement of 10 mm), as observed by Digital Image Correlation images of the flexural tests. Coated basalt reinforcements thus outperform in flexural applications. • Tensile properties of unimpregnated and impregnated basalt yarn are characterized. • The flexural behavior of thin basalt-reinforced concrete beams is investigated. • The impact of reinforcement volume fraction and textile coating is discussed. • A crack analysis is performed at two different deformation states of the composite. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate and compare the effects of using pigment and glass fibers on the mechanical properties of reactive powdered concrete (RPC). The materials used included Portland cement, aggregates, water, pigment, and glass fibers (GF). In the first phase, 33 mix designs were examined, involving various pigment percentages (3 %, 5 %, 7 %) and sand-to-cement ratios, under two curing conditions (40 % and 50 % calcium carbonate). The results showed that adding pigment led to reductions in the compressive, flexural and tensile strengths, as well as increased water penetration. These negative impacts worsened as the pigment percentage increased. Therefore, the 3 % pigment mix design was selected as the reference sample for the second phase. In the second phase, 26 mix designs with different GF percentages (8 %, 10 %, 12 %) and sand-to-cement ratios were tested under the same two curing conditions. Subsequently, the compressive strength tests were conducted on different curing days (1, 7, 14, 28, 42, 56, 90 days), as well as the flexural strength, tensile strength, and water penetration tests according to standard procedures on all samples. The findings demonstrated that the compressive strength improved with higher GF content, up to 10 %. However, 12 % GF caused a decrease in the compressive strength compared to 10 % GF. The 10 % GF mix exhibited the highest the tensile and flexural strength, and lowest water penetration. In conclusion, it can be said that the mix design with the sand to cement ratio of S1.2C40 is the most suitable mix design from both economic and the compressive strength perspectives. This mix design creates a desirable balance between increased strength and reduced costs, and can be useful for practical applications. • Adding pigment led to a reduction in compressive, flexural, and tensile strength and an increase in water penetration. • The mix design with 3 % pigment was chosen as the reference sample for the second step. • The sample with 10 % glass fibers exhibited the highest tensile and flexural strength and the lowest water penetration. • The sand-to-cement ratio of S1.2C40 is the most suitable mix design from both economic and compressive strength perspectives. [ABSTRACT FROM AUTHOR]

Fiber reinforced thermoplastic composites have many advantages, such as repeated molding, high toughness, durability and recyclability, which made them a potential substitute as engineering strengthening materials for thermosetting composites. However, their long-term performances under complex service environments are not well understood, hindering its durability design. In the present paper, glass fiber reinforced polypropylene (GFRPP) plate was studied on its mechanical property evaluation subjected to water immersion (distilled water) and bending (bending strains of 0.54 % and 1.04 %) at elevated temperatures (40 °C, 60 °C and 80 °C) up to 180 days. Water uptake, mechanical properties, thermal properties and microstructure tests were further carried out to reveal the effects of water uptake content, immersed temperature and bending loading level on the properties. The results showed the water absorption curve at three temperatures presents a two-stage diffusion behavior. After the longest immersion time of 180 days, the strength retention of plate at 40 °C, 60 °C and 80 °C were 88.2 %, 58.3 % and 31.8 % for tensile strength, 83.6 %, 67.8 % and 47.9 % for flexural strength and 70.6 %, 61.7 % and 41.4 % for in-plane shear strength. Higher immersion temperature accelerated the swelling effects of polypropylene. Higher bending loading levels accelerated the crack or defects formation and propagation in the resin as well as at the interface. When the strength retention rates were 50 %, the longest service life of plate exposed in service environment of Da Lian (T=9.2 °C) were 23.9 years (tensile strength), 12.8 years (flexural strength) and 3.0 years (in-plane shear strength) without the bending strain. Through comparing with thermosetting composites, glass fiber reinforced polypropylene has almost close or higher tensile strength retention rate and service life for certain service conditions. • The maximum water absorption and diffusion coefficient of composites were lower than epoxy or polyurethane based composites. • Higher immersion temperature accelerated the swelling effects of polypropylene. • Higher bending loading levels accelerated the crack or defects propagation in the resin as well as at the interface. • When the strength retention rates were 50 %, the longest service life of tensile strength were 23.9 years. [ABSTRACT FROM AUTHOR]

Geopolymer technology is a spectacular technique which provides solutions to several construction problems in a sustainable way. In the primary stage of this research, geopolymer mortar using industrial and agro wastes, such as fly ash and sugarcane bagasse ash (SCBA) was developed. It was found that the geopolymer mortar with 10% SCBA shows good mechanical and durability properties. In the second stage of this research, engineered geopolymer mortar (EGM) using 10% SCBA content and polypropylene (PP) fiber was developed. In the final stage of this study, a novel strengthening system made of fabric-reinforced engineered geopolymer mortar (FREGM) composites was developed using EGM and glass fabric. To characterise mechanical response, the FREGM material has been subjected to flexural and tensile tests. It was discovered that 4-layers of glass fabrics attained 21.87 MPa flexural strength. The feasibility of practical applications of this newly developed FREGM material was checked by using it for strengthening the cylindrical and beam specimens. For the cylindrical specimen, the test variables include methods of installations (cast-in-place and prefabricated), number of glass fiber fabrics, and test temperature (200 °C, 400 °C and 600 °C). The cast-in-place cylinder specimen achieved 6% higher load carrying capacity than the precast cylinder, and 30% higher load carrying capacity than the control specimen. The beam specimens strengthened with geopolymer mortar, EGM and FREGM materials performance were evaluated by studying the load- deflection behaviour, cost analysis, ductility factor, crack and installation methods (cast-in-place and prefabricated). It is found that the cast-in-place beam specimen achieved 9.5% more strength than the precast beam and 46% higher than the control specimen. [Display omitted] • Developed Engineered geopolymer material using agro and industrial waste materials. • Developed a new fabric-reinforced engineered geopolymer mortar (FREGM) composite. • Checked the efficiency of developed FREGM composite by strengthening the cylinder and beam specimens. • Temperature study on FREGM strengthened cylinder specimen. [ABSTRACT FROM AUTHOR]

The combined need to propose new solutions for the structural reinforcement of existing buildings and for the reduction of CO 2 emissions is leading to the development of more sustainable composite materials, such as those based on alkali-activated mortars (AAM). In this study, different formulations of AAM, based on metakaolin or fly ash, have been evaluated as possible matrices for Textile Reinforced Mortar (TRM) systems. Two different bidirectional textiles, made of AR glass or basalt fibers, were used as internal reinforcement. The physical-mechanical properties of TRM systems based on AAM were evaluated and compared with those of commercial systems with cementitious or lime-based matrices. Direct tensile tests on TRM coupons and shear bond tests on clay brick substrates were carried out. Then, their energy and environmental-related performance have been compared. Results showed that alkali-activated matrices can be very promising and eco-friendly alternative solutions to traditional mortars in TRM systems. • Development of alkali-activated mortars (AAMs), to be used as inorganic matrices for Textile Reinforced Mortar (TRM) systems. • Physical-mechanical characterization of TRM composites based on AAMs and comparison of performances with commercial TRM systems. • Evaluation of the Environmental and Energy performances, in relation to the obtained mechanical performances, of different TRM systems. [ABSTRACT FROM AUTHOR]

Glass fiber reinforced plastics (GFRP) have been widely used in the field of civil engineering infrastructure, while it also generating a large amount of waste glass fibers simultaneously. This paper uses waste glass fiber in self compacting recycled concrete (SCRC), forming a kind of waste glass fiber reinforced self-compacting recycled concrete (RGF-SCRC). The effects of recycled coarse aggregate (RCA) replacement ratio, water to binder (W/B) ratio, the content and type of glass fiber on the working and mechanical properties of RGF-SCRC were investigated. The results showed that the specimens could meet the requirements of self-compacting concrete (SCC) in terms of working performance, but the addition of RCA and glass fiber could reduce the workability of RGF-SCRC, when RCA is replaced with 100 % and the fiber content reaches 10 kg/m3, the slump expansion is reduced by 9.5 % and 12.4 %, respectively. The mechanical properties of RGF-SCRC decreased as the growing value of RCA replacement ratio and the W/B ratio, among them, the elastic modulus decreased the most, by 40.4 % and 30.0 %, respectively. Compared with the results of the control specimen, the properties could be improved significantly under an appropriate content of waste glass fiber: the cube compressive strength, splitting tensile strength, flexural strength, and elastic modulus of RGF-SCRC were increased by 1.3∼9.6 %, 13.5∼59.4 %, 17.8∼40.9 %, and 3.3∼13.4 %, respectively. However, excessive fiber content showed a negative effect on the mechanical properties. Specimens with the 7.5 kg/m3 alkali resistant glass fiber content showed the best mechanical properties. Moreover, the X-ray CT and scanning electron microscope (SEM) techniques were applied to explore the influencing mechanism of waste glass fibers on RGF-SCRC. The results showed that after adding an appropriate content of waste glass fiber, the porosity and the number of large pores decreased, and the pore size and distribution became more reasonable, which enhanced the compactness of RGF-SCRC to some extent. The mechanical force and friction force anchored at the fiber end at the interface with the concrete matrix increase the bonding strength, thereby enhancing the mechanical properties of RGF-SCRC. This study achieve the resource utilization of waste glass fiber and improve the mechanical properties of concrete and the research results can provide a reference for the practical application of RGF-SCRC in civil engineering. • The waste glass fiber was applied in self compacting recycled concrete (SCRC). • Various parameters were investigated to make clear the influential mechanisms of glass fiber on the working and mechanical properties of waste glass fiber reinforced self-compacting recycled concrete. • The enhanced mechanism of fiber addition on SCRC was illustrated by the microstructure method and analysis. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and analytical study about the sound insulation of innovative sandwich panels - named EasyFloor – for the rehabilitation of degraded timber floors in old buildings. Two types of panels were developed: (i) an all-composite sandwich panel, made of glass fibre reinforced polymer (GFRP) face sheets and webs, and polyurethane (PUR) foam; (ii) and a hybrid sandwich panel, where the top face sheet comprises a thin layer of concrete. The study included the comparative analysis of the airborne sound reduction and impact sound pressure level of both types of panels based on experimental tests on full-scale specimens, including a typical floor covering. The acoustic insulation properties determined experimentally were compared with predictions from different analytical models typically applied to sandwich panels, and also with performance requirements defined in building regulation. Among the different analytical models that were assessed, Sharp's model provided the most accurate predictions when considering the natural and dilatation frequencies as the critical frequency. The comparison of the normalized airborne and impact sound indices determined experimentally with requirements set in building regulation shows that the use of GFRP-PUR panels in the rehabilitation of lightweight timber floors and in new construction, where building comfort requirements are stricter, require mitigation measures to improve sound insulation. • Acoustic behaviour of web-core all-composite and hybrid sandwich panels. • Airborne and impact sound insulation tests. • Influence of panel architecture and effects of resilient floor covering. • Assessment of different analytical models for sound reduction prediction. • Comparison with building comfort requirements. [ABSTRACT FROM AUTHOR]

With the increasing application of textile-reinforced mortars (TRMs) for the strengthening of existing masonry structures, knowing the long-term behavior of these composites is increasingly of great importance. In recent years, there has been a progressive research effort on the durability of TRM composites following different aging protocols, yet the durability of TRMs still necessitates comprehensive experimental studies for a better understanding of their behavior. On the other hand, there is also a lack of established aging methods, including acidic attack. The present study aims to leverage knowledge of the durability of TRMs when exposed to acidic attack. For this purpose, two different commercial fabrics made of glass and basalt fibers and a lime-based mortar have been used. In parallel, two aging conditions were also investigated considering 1000, 3000, and 5000 hours of exposure. Overall, a total number of 462 specimens were tested, including tests for the matrix, fabric, and composite. Compressive, flexural, and elastic modulus tests studied the variation in the mechanical properties of mortar, tensile tests focused on the textiles, and pull-out and single-lap shear tests were used for TRM composite's behavior. To investigate possible changes in material behavior due to aging, mineralogical and chemical analysis including Optical Microscopy, SEM, XRD, and TGA were carried out. • Investigating the long-term behavior of textile-reinforced mortars (TRMs), addressing the importance of their durability. • Implementation a campaign involving 462 specimens, using glass and basalt with a lime-based mortar under acidic conditions. • Investigating the effect of the acidic environment on the behavior of both the constituent's component and the composite. • implementing the standard material characterization tests, and pull-out and single lap for the TRM composites. • Microstructural investigation over the aged mortar including XRD, SEM, TGA, and optical microscopy. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation into the improvement of efficiency in carbon fibre reinforced polymer (CFRP)-to-concrete bonded joints by an introduction of a glass fibre reinforced polymer (GFRP) interlayer. By introducing a ±45° biaxial GFRP interlayer between the CFRP and concrete, applied force on the CFRP laminate was distributed over a larger area of concrete surface, thereby increasing the load carrying capacity of the bonded joint. A total of 18 single-shear pull test specimens were prepared and tested to investigate the effect of CFRP width (varying from 25 mm to 50 mm) and GFRP/CFRP width ratio (ranging from 2 to 4) on the behaviour of the CFRP-to-concrete bonded joints with a GFRP interlayer. Addition of the GFRP interlayer was found to increase both ultimate load capacity and the deformation capacity significantly. Increase in the GFRP interlayer width, while keeping the CFRP width the same, increased the ultimate load of the bonded joint. Increasing the GFRP width while keeping the GFRP/CFRP width ratio the same also increased the ultimate load of the bonded joint but had little effect on the bond strength. An idealized mechanism was presented to explain the behaviour of the CFRP-to-concrete bonded joints with a GFRP interlayer. It was shown that due to 2D stress transfer of the newly proposed bonded joints, underlying mechanisms may be different to the conventional FRP-to-concrete bonded joints. Therefore, design theories developed for conventional FRP-to-concrete bonded joints may not be directly applicable to the CFRP-to-concrete bonded joints with a GFRP interlayer. Much more investigations are necessary to better understand the behaviour of the newly proposed bonded joints. • A biaxial GFRP interlayer was introduced between CFRP and concrete in CFRP-to-concrete bonded joints to improve the load carrying capacity. • Both ultimate load and the ultimate displacement of the bonded joints were significantly increased. • Fracture area within concrete was significantly increased with the introduction of the biaxial GFRP interlayer. • Width of the GFRP interlayer increased the ultimate load of the CFRP-to-concrete bonded joints. [ABSTRACT FROM AUTHOR]

The research on hybrid fiber reinforced polymer (FRP) composites in civil engineering has emerged recently, but there is a lack of durability test data for common environmental conditions such as the marine and moist environments. Due to the presence of four failure modes in hybrid FRP composites, the applicability of durability findings from conventional FRP composites cannot be directly extrapolated to them. In the present study, the hybrid FRP composite composed of glass and polypropylene fiber was subjected to immersion in salt solution or deionized water at varying aging temperatures (20, 40, and 60 °C) for different durations of aging (30, 60, 90, and 120 days). The accelerated aging tests were primarily aimed to evaluate the tensile properties and microstructural changes of hybrid FRP composites. Test results demonstrated that both salt solution and deionized water exert a significant influence on the tensile properties of hybrid FRP composites, with the former exhibiting a more pronounced impact. The aging mechanism primarily involves degradation of the glass fiber and the epoxy matrix in hybrid FRP composites. The design recommendation for first limit stress of hybrid FRP composites aligns with that of glass FRP as specified in Chinese standard GB 50608–2010, while it recommends a retention rate of 0.7 for second limit stress. Other mechanical parameters (elastic modulus, second limit strain, and second modulus) can be considered independent of environmental factors. Furthermore, maintaining a glass fiber layer volume fraction below 12.3 % is beneficial for the long-term performance of hybrid FRP composites. • The failure mode of hybrid FRP remains unchanged even after aging. • The first limit stress of hybrid FRP decreases significantly after aging. • Reducing glass layer volume fraction can improve the durability of hybrid FRP. [ABSTRACT FROM AUTHOR]

This study explores developing and characterizing a one-part geopolymer, an innovative and sustainable construction material. The effects of incorporating polyvinyl alcohol (PVA), polyethylene (PE), and glass fibers (GF) on the toughness of slag and fly ash-based one-part geopolymer mortars were investigated through compressive, three-point flexural, and four-point bending tests. The findings demonstrate that fiber incorporation reduces fluidity and compressive strength due to increased porosity, lower elastic modulus of fibers, and weak interfacial bonding. However, fibers significantly enhance damage resistance and toughness via crack bridging and load transfer mechanisms. Formulations with 2 % PVA fibers and combinations of 1 % PVA with 1 % PE fibers and 1 % PVA mixed with 0.5 % PE and 0.5 % GF demonstrate excellent toughness. Notably, the latter two fiber blends achieve 14 % and 10 % cost reductions, respectively, compared to using only PVA fibers, making them economically viable for large-scale applications. Scanning electron microscopy and X-ray diffraction provided insights into the toughening mechanisms, including crack bridging, fiber pull-out, and enhanced stress distribution within the geopolymer matrix. Digital image correlation techniques further elucidated the fibers' role in improving the post-cracking behavior and structural resilience under load. • Comprehensive investigation of PVA, PE, and glass fiber reinforcement in one-part geopolymer mortars, focusing on toughness optimization and cost-effectiveness. • Fiber incorporation significantly enhances damage resistance and toughness through crack bridging and load transfer mechanisms, despite minor reductions in fluidity and compressive strength. • Economically viable fiber blends (1 % PVA + 1 % PE; 1 % PVA + 0.5 % PE + 0.5 % GF) achieve excellent toughness with 14 % and 10 % cost reductions, respectively, compared to using only PVA fibers, making them suitable for large-scale applications. • SEM and XRD provide insights into the toughening mechanisms, including crack bridging, fiber pull-out, and enhanced stress distribution within the geopolymer matrix. DIC techniques elucidate the fibers' role in improving the post-cracking behavior and structural resilience under load, further validating the effectiveness of fiber reinforcement in one-part geopolymers. [ABSTRACT FROM AUTHOR]

Geopolymer (GP) materials are attracting increasing interest as a promising alternative to conventional cement-based materials, due to their beneficial characteristics. This article presents the preparation of two series of GP composites based on natural pozzolan (Pz), reinforced with varying percentages (0, 0.5, 1, 1.5, and 2 %) of short fiberglass waste rich in zirconia (Zr-GFW). Two alkaline activation solutions were used with a 1:1 ratio: NaOH (10 M): Na 2 SiO 3 for the first series, and NaOH (12 M): Na 2 SiO 3 for the second series. The effect of Zr-GFW incorporation on the structural, physical, mechanical, and chemical properties was investigated. Besides, a comparison between the two series with the different concentrations of alkaline solutions was also discussed. XRD analysis shows that no significant reaction occurred between zirconia and Pz-based GP matrix. The results show that a 1 % Zr-GFW is sufficient for excellent mechanical strength, up to 65 MPa, and good physical properties. Furthermore, based on the Box-Behnken design statistical method, the developed response surface methodology model shows a strong fit to the experimental data, with high values of R² (0.9998). In this model, the compressive strength studied is 64.28 MPa. After exposure to an 80 % solution of acetic acid for 60 days, the evaluation of chemical durability showed that the dense structure of the studied GP composites resisted the acid attack tests, as confirmed by SEM analysis. The percentage weight loss (%W L) of the GP composites ranges from 14.66 % to 16.15 %, resulting in a decrease in compressive strength of up to 55 %. However, this reduction is better than several previous works. The findings suggest that these GP composites not only contribute to waste management but also enhance the energy performance of buildings. [Display omitted] • GP composites were prepared with pozzolan and varying amounts of short fiberglass. • Alkaline activators included aqueous solutions of NaOH (10 or 12 M): Na 2 SiO 3. • GPs reinforced with 1 % fiberglass have the highest compressive strength. • After 60 days in an 80 % acetic acid solution, the %W L varies from 14.66 % to 16.15 %. • These new GP composites enhance building energy performance and waste management. [ABSTRACT FROM AUTHOR]

To achieve sustainable development and reduce the carbon footprint in building material production, the E-glass fiber mat was impregnated with basic magnesium sulfate cement (BMSC) by lamination impregnation. This process reduces environmental pollution from cement preparation, increases fiber volume content, and enhances the mechanical properties of cementitious composite materials. The study examined axial tensile, four-point bending resistance, drop weight impact resistance and pendulum impact resistance of BMSC thin-slab reinforced with dispersed short glass fiber (SGF), short glass fiber mat (SGFM) and continuous glass fiber mat (CGFM) of varying gram weights. The results show that the mechanical properties of BMSC thin-slab reinforced with fiber mat are much higher than those of SGF reinforced thin-slab. The tensile strength of BMSC thin-slab reinforced with CGFM is higher than that of BMSC thin-slab reinforced with SGFM at the same gram weight, and the tensile strength increases as the weight of CGFM increases. Specifically, the axial tensile strength of BMSC thin-slab reinforced with 450 g of CGFM is nearly 8 times higher than that of SGF reinforced BMSC thin-slab. BMSC thin-slab reinforced with 450 g of CGFM has the maximum proportional limit load and bending strength. The impact strength and toughness indexes of BMSC thin-slab reinforced with CGFM are the highest, followed by SGFM reinforced BMSC thin-slab. The addition of 300 g CGFM significantly enhanced flexural toughness during the early stage of thin-slab cracking, while 450 g CGFM showed significant improvement in flexural toughness during the middle and late stages of cracking. When comparing thin-slabs with the same glass fiber volume ratio, those reinforced with 450 g CGFM exhibited the best impact resistance. SEM results indicated superior adhesion between 450 g CGFM and the cement matrix, as well as between adjacent CGFM layers, with fiber breakage being the main cause of specimen failure. • E-glass fiber mat reinforced basic magnesium sulfate cement thin-slab was prepared. • Fiber volume reached 18 %. • The strength and toughness of 450 g continuous fiber mat reinforced thin-slab are the best. • 450 g continuous fiber mat reinforced thin-slab has the best impact resistance. [ABSTRACT FROM AUTHOR]

Biobased polymers are gaining increasing popularity particularly within key industries such as construction and building materials. However, glass fiber-reinforced polymer composites (GFRCs) based on biobased epoxy thermoset are inherently vulnerable against fire, producing huge fire hazards and eventually loss of structural integrity. In this work, a cobalt-based nanohybrid filler (CNH) was designed and synthesized to act as a high-performance synergist for biobased epoxy resin when combined with phosphorous flame retardants (FRs). An optimized formulation was found, resulting in a flame-retarded epoxy resin with a limiting oxygen index (LOI) value of 39.7 % and a V 0 rating in the vertical burning test. The GFRCs were then fabricated with optimized formulation. Interestingly, results showed that the percentage of peak heat release (PHRR) rate reduction was retarded from 74 % for the mixed resin to 36 % for GFRCs, potentially due to the interference of glass fiber. The optimized laminate with CNH showed improved mechanical properties at ambient temperature. Additionally, delayed time-to-failure values were found when sample coupons with CNH were subjected to a constant axial force loading while being ignited and burning, indicating higher resistance against fire for mechanical integrity. • Nanohybrid were first used for flame retarded fiber-reinforced biocomposites. • Interesting flame retardancy mode transfer was found from resin to composites. • Optimized laminate showed delayed failure time under simultaneous fire and load. [ABSTRACT FROM AUTHOR]

This paper shows the physicochemical and mechanical characterization of a new plaster material lightened with superabsorbent polymers (SAP) and reinforced with fibers. First, an experimental campaign has been conducted to determine the ideal quantity of sodium polyacrylate polymer (NaPA) to be added, analysing three water/plaster ratios and three different amounts of SAP. The aim is to achieve the maximum reduction in density and optimal mechanical resistance. Once this analysis was conducted, a 0.7 water/plaster ratio and 0.015 SAP/gypsum ratio were determined as the ideal mixture. With this, a complete characterization of the new material was conducted, also considering the incorporation of three different fibers. SAP addition led to a significant apparent density reduction in the new plaster compounds produced, reaching values up to 27 % lower than the reference samples. From those samples with fibers, kevlar and glass fiber got a better mechanical performance, always exceeding the limit values established by current regulations. In the same way, the incorporation of these superabsorbent polymers has managed to reduce the original plaster material thermal conductivity by up to 32 %, as porosity increased. Thus, it has been confirmed that the incorporation of superabsorbent polymers in the production of plaster compounds is a viable alternative to produce lightweight prefabricated elements within wide field of application for the design of new prefabricated elements. • Density of this new plaster-based material is around 25 % lower than plaster. • Thermal conductivity decreased significatively in this new material. • SEM helps to understand the internal structure of the material developed in this investigation. • Mechanical resistance decreased but it can still be used in building precasts. [ABSTRACT FROM AUTHOR]

Recycled glass fibers from wind turbine blades have significant potential for enhancing the performance of asphalt mixtures. However, the impact of residual polyurethane (PU) components on asphalt performance remains uncertain, presenting a challenge to the high-value utilization of wind turbine blades in pavement engineering. This study investigates the effects of waste polyurethane (WPU) on the rheological properties and compatibility of SBS modified asphalt, widely used in pavement engineering under various temperature conditions. Molecular dynamics (MD) simulations were employed to analyze the underlying mechanisms. The results reveal that incorporating WPU improves the rutting factor and creep recovery rate of SBS modified asphalt, demonstrating superior high-temperature performance compared to SBS modified asphalt alone. The synergistic effect of WPU and SBS significantly enhances low-temperature crack resistance and overall asphalt compatibility. Additionally, the interaction between SBS and the four components of asphalt is strengthened, and diffusion mobility is reduced due to WPU incorporation. This indicates that WPU promotes a more compact structure and a higher relative concentration of SBS and the four components within the spatial system, thereby enhancing the stability of the WPU/SBS modified asphalt system. Furthermore, using WPU in asphalt mixtures not only avoids environmental pollution compared to traditional disposal methods but also offers considerable long-term economic benefits. Overall, WPU positively impacts the rheological properties and compatibility of SBS-modified asphalt, suggesting that processed wind turbine blades can be a viable solution for enhancing asphalt mixture performance. • WPU from the surface of glass fibers stripped from wind turbine blades can enhance the performance of SBS modified asphalt. • The synergistic interaction between WPU and SBS significantly enhances the low-temperature crack resistance and compatibility of the asphalt. • WPU promotes a tightly structured and uniformly distributed system between SBS and asphalt components. [ABSTRACT FROM AUTHOR]

With escalating demand for concrete and associated burden on natural resources, seawater sea-sand concrete (SWSSC) has been proposed as a sustainable alternative to normal concrete (NC). With the implementation of SWSSC, glass fiber reinforced polymer (GFRP) bar is considered as a promising replacement to conventional steel reinforcements to address the chloride-induced corrosion issue. This study comprehensively investigates the bond strength of GFRP bars embedded in either NC or SWSSC with normal-strength (grade C55) and high-strength (grade C80) mix designs. Moreover, early-age microstructure (including heat flow, micromorphology, components, and pore structure) and mechanical properties (including compressive strength and Young's modulus) of concrete matrix are analyzed in depth to uncover the load transfer mechanism at the GFRP-concrete interface. Results indicate that saline contents in SWSSC lead to a notably denser microstructure and higher early-age GFRP-concrete bond strength compared to NC for the normal-strength mixes (i.e., 15.5% increase in bond strength with 28-day curing), while such increase is limited for the high-strength groups (i.e., 3.2% increase). Furthermore, no significant decline in the long-term bond performance is observed under accelerated hydrothermal aging conditions. Also, experimental results are employed to evaluate the relationship between bond strength and concrete compressive strength as stipulated in the ACI design guideline, yielding pertinent recommendations for potential enhancements. • Behaviour and durability of GFRP-SWSSC bond was comprehensively investigated. • Various parameters (concrete type and grade, bar size, etc.) were considered. • Mechanical and microstructural tests were performed for possible correlations. • Assessment of existing design guideline was carried out with relevant suggestions. • The results are useful for wider application of GFRP in engineering practice. [ABSTRACT FROM AUTHOR]

Glass Fiber-Reinforced Polymer (GFRP) bars can enhance the flexural bearing capacity and durability of concrete beam members under sustained loading and alkaline environment over an extended period. However, addressing the challenges related to durability and deformation resistance remains crucial for long-term service. In this paper, the flexural performance of GFRP-reinforced concrete beams with different glass fiber contents under the coupling action of the alkaline environment and continuous load is studied, and the mechanism of improving the flexural performance of GFRP-reinforced concrete beams by dispersed fibers is analyzed from a microscopic point of view by scanning electron microscope (SEM) test. In addition, the finite element analysis software was used to simulate and verify the improvement effect of singly dispersed fiber on the bending of GFRP-reinforced concrete beams. The results demonstrate that GFRP-RC beams containing 0.5%, 1.0%, or 1.5% glass fiber exhibit a reduction in deflection ranging from 11% to 23% compared GFRP-RC beams without glass fiber, thereby improving their deformation resistance. The optimal glass fiber content is 1.5%. Simulation analysis demonstrates that the model exhibits enhanced resistance to deformation when the glass fibers are randomly dispersed. Specifically, increasing the random scattering of fibers at the bottom of the beam by two to three times results in a reduction of 7%-12% in mid-span displacement of the model. Additionally, within the cracked area, the fibers bear greater tensile stress compared to those in other uncracked regions, effectively preventing further cracking of GFRP-RC beams. This study offers valuable design guidance for enhancing performance of GFRP-RC members during long-term service. • This paper studied glass fiber GFRP-RC beams. • The working condition is the coupling of sustained loading and alkaline environment. • The influence of fiber on the flexural property of beam was investigated by finite element method. • The corrosion age of alkaline environment is 450 d. [ABSTRACT FROM AUTHOR]

Reinforcement bars based on glass fibre reinforced polymers (GFRP) show good mechanical properties and advantageous durability properties compared to conventional steel reinforcement. The increasing use of GFRP reinforcement can, therefore, also be seen against the background of an advised resource-efficient adoption of materials in the construction industry. However, the mechanical properties of GFRP reinforcement are still not sufficiently researched, currently leading to regulatory restrictions. More specifically, regarding the compressive material properties of GFRP reinforcement bars under long-term loading, there is a significant lack of information. This paper introduces a novel model for predicting the stress redistribution in GFRP reinforced concrete members subjected to long-term compression. A comprehensive examination of the mechanical background and a brief summary of existing literature on relevant test results form the basis for the initial development of an extensive test program to be applied. In the first part of the experimental investigations, GFRP reinforcement bars are statically loaded for an experimental period of 1000 hours in order to determine creep rates. Subsequently, GFRP reinforced concrete specimens are subjected to compression for 190 days at three different load levels. The results show a significant stress increase in the GFRP reinforcement due to creep and shrinkage. The high ultimate loads of preloaded specimens demonstrate that the long-term loading did not lead to any damage. The proposed analytical model combines the two parts of the experimental program and provides a practical method for determining the load redistribution in GFRP reinforced concrete members under permanent compressive loading. • Experimental determination of GFRP compressive creep behaviour. • Determination of a GFRP compressive creep model. • Investigation of creep induced GFRP load share to compressive capacity. • Assessment of shrinkage induced GFRP load share to compressive capacity. • Model proposal for the load-redistribution in compressed GFRP RC members. [ABSTRACT FROM AUTHOR]

The textile-reinforced mortar (TRM) combines high-strength fabric textiles with cementitious mortar matrix to enhance mechanical behaviour and durability, especially at high temperatures. The current study investigated how basalt, carbon, and glass textile grids and TRM composites respond under direct tensile and thermal loading up to 800 ℃. Changes in microstructure were analyzed using scan electron microscopy (SEM), thermo-gravimetric analysis (TGA), and ultrasonic pulse velocity (UPV). The results indicated that temperature significantly affected the coating material and cementitious mortar, weakening the grids and composite specimens. Carbon and glass fibre grids proved more resilient, and the carbon and glass TRM reduced 50% of their ultimate stress at 500 ℃, while for basalt TRM is 200 ℃. A slight gain of strength was observed for all TRM specimens at 300 ℃, and SEM analysis revealed critical changes in the mortar matrix and interfacial transition region. The results were further utilized to calibrate the Gibson model considering humidity and early-stage coating material changes, and yielding results consistent with experimental data. • The thermomechancial tensile behaviour of basalt, carbon, and glass fabric TRM and textiles were presented. • The experimental results were further investigated with the use of a analytical model. • The micro-level experiments were conducted to study the variation under high temperatures. [ABSTRACT FROM AUTHOR]

Fiber reinforced thermoplastic composite bars offered the advantages of repeated molding, high toughness, and recyclability, making them a promising alternative to steel bars. For the stirrups applications in concrete structures, it was essential to develop efficient bending technologies for producing high-quality thermoplastic bending bars. In the present paper, the bending properties of glass fiber reinforced polypropylene (GFRPP) composite bars were investigated by experimental and theoretical methods. A novel bending fixture of GFRPP bars was specifically designed for GFRPP bars to ensure the reliable bending of the bars. Finite element simulation was employed to analyze the stress distribution of GFRPP bars, providing valuable insights into their mechanical behavior. Additionally, a bending strength model was developed based on the material mechanics, offering a theoretical framework for understanding and predicting the bending strength of GFRPP bars. Finally, the bending mechanism of bars was further revealed according to experimental and theoretical findings. The results of the study demonstrated that the specially designed bending fixture was successful in minimizing damage to the bending section of the GFRPP bars, leading to a significant improvement in bending strength retention of up to 43.2 %. Furthermore, the theoretical results and experimental test have a good agreement in terms of stress distribution and failure mode. The maximum strain in the transition zone between the straight section and the bending section of the GFRPP bars was nearly double that of the straight section at the same stress levels. With the increase of bending radius to diameter ratio from 3.0 to 7.0, the tensile strength of GFRPP bending bars increased by ∼7.9 %. The study identified the transition area between the bending section and straight section of GFRPP bars as the most critical failure point. The strength degradation mechanism during the bending were attributed to the shrinkage and torsion of inner fibers owing to the compression caused the local stress concentration, which caused the inner resin matrix to crack and interface debonding of fiber/resin, leading to the premature tensile failure. • The bending fixture can achieve the high bending strength retention up to 43.2 %. • Theoretical and experimental results verified the most unfavorable failure point. • Larger bending radius contributed to the decrease ∼7.9 % of tensile strength. • Fiber distortion and interface debonding led to tensile failure of bending bars. [ABSTRACT FROM AUTHOR]

The study presents the experimental investigation of bond performance of normal and high-strength geopolymer concrete and Glass Fibre Reinforced Polymer (GFRP) bars. The effects of bar diameters, embedment lengths, and concrete grades on maximum pullout load and failure characteristics are investigated. When the adhesive and residual strengths of GFRP bond specimens were compared to steel specimens, the former demonstrated remarkable performance despite having differing surface properties. An energy-based equivalent bond strength approach is proposed to examine pre-peak bond performance, which demonstrating that the decreasing rate of strength is faster for higher diameter and embedment, showing a drop in bond performance. Pullout failure was noted in smaller diameter bond specimens, where the shear strength between the ribs and the GFRP bar controlled the bond strength. Concrete split failure occurs for 12 mm specimens with embedment lengths greater than 5d in both GPC40 and GPC60. Specimens with 16 mm, excluding G-16-5d-60, demonstrated concrete split failure for all embedment lengths and concrete grades; bond strength is determined by the concrete shear strength. Enhancing the concrete's compressive strength has a beneficial impact on the bond strength as it increases ranging, from 14.57 to 32.12%. Analytical models such as mBPE and CMR were employed to derive the mathematical expression for the bond stress versus slip curve. It was found that the curves of CMR model were typically closer to experimental curves than the mBPE model. • Bond performance of the GFRP bar with normal and high-strength geopolymer concrete is studied. • Effect of bar diameter, embedment length, and compressive strength of concrete on bond performance is investigated. • Existing analytical model are compared with the experimental results. • Energy-based equivalent bond strength is proposed to study the bond performance. [ABSTRACT FROM AUTHOR]

The goal of this research is to improve the mechanical characteristics and durability of concrete while adhering to green and sustainable development principles. Portland cement (PC) was replaced with ceramic waste powder (CWP), glass powder (GP), and granite waste powder (GWP) to create the low-carbon, high-strength concrete (HSC). These materials were incorporated at 0–50% as a partial replacement of PC. The short alkali-resistant (AR-) glass fiber content was added by 1.0% of the PC content. The changes in strength, microstructure, pore structure, as well as ecological assessment of HSCs was investigated. Various experiments on the durability properties and elevated temperature resistance of HSC were performed. The experimental results show that mechanical properties of HSC with 10%GP and 20%GWP were maximally enhanced at 28d, while the mechanical properties of HSC with 50% of all wastes are decreased. It was found also that HSC containing CWP showed significant reductions in carbonation depth (up to 65.89% lower than the control mixture), especially at higher replacement levels. Furthermore, the increment in substitution level of CWP has found an increment in pore volume, resulting in a reduction in preliminary strength performance. It was observed that a 50% substitution level of GP and GWP reduced the water penetration depth by 47.71% and 65.7% compared to the control mixture, respectively. The residual strength after 600 °C exposure for 10%CWP, 10% GP, and 20% GWP retained about 34.10%, 32.32%, and 43.29%, respectively, from their original strength. XRD tests and SEM micrographs showed that adding 10%GP and 20%GWP improve the hydration reactions. Finally, environmental assessments revealed that incorporating CWP, GP, and GWP into HSC led to reduced costs, energy consumption, and carbon footprint. • Ceramic, glass, and granite waste were used as SCMs to produce a low-carbon high strength concrete. • Granite waste powder as partial replacement of PC enhanced carbonation resistance of high strength concrete. • Glass and granite waste show more thermal stability than the control mixture. • Ceramic, glass, and granite powder reduces the overall cost and carbon emissions. • Incorporation of 20% granite powder improves microstructure of concrete significantly. [ABSTRACT FROM AUTHOR]

To improve the fatigue behaviour of the concrete, this paper explored a potential innovative method: the joint addition of expansive agents (EA) and glass fibres (GF). It was envisaged that the addition of EA reduced additional defects caused by the addition of GF to the concrete, while the compressive prestress caused by EA enhanced the bonding between GF and the concrete, thereby improving the fatigue behaviour of the concrete. The test results indicated that the synergistic effect of EA and GF effectively improved the static bending strength, fatigue life, and deformation performance of the concrete. The synergistic effect of EA and GF on the fatigue life of the concrete was revealed qualitatively and quantitatively. The synergistic effect was further demonstrated from perspectives of the fatigue deformation and fatigue stiffness. Furthermore, P - S - N curves of EA and GF reinforced concrete were established, and the fatigue ultimate strength and conditional fatigue ultimate strength were provided as a design basis. This paper recommended adding an appropriate amount of EA to glass fibre reinforced concrete to achieve better concrete properties. • Joint addition of EA and Gf was a potential method for improving concrete. • Bending tests were used to elucidate fatigue bending performance of concrete. • Synergistic effect of EA and GF on fatigue performance of concrete was reveal. • Using two-paramater Weibull distribution, P - S - N curves were established. [ABSTRACT FROM AUTHOR]

In the asphalt pavement with semi-rigid base, the shrinkage cracks initiating from base course often propagate upward to surface course to develops into reflective cracks. The fiberglass grid, as a woven geotextile, is widely used to retard the occurrence of reflective cracks in China, but the impacts of material composition and knitting methods of it on reflective cracks are still not clear. In this paper, two kinds of models, including a two-scale model of fiber bundle-fiberglass grids layer and a coupled thermo-mechanical model of pavement structure, are established. In the two-scale model, the elastic constants (ECs) of fiber bundle and fiberglass grids layer are calculated under different compositions and knitting methods and then assigned to the coupled thermo-mechanical model to estimate the fatigue lives at initiation phase (FL-IP) and propagation phase (FL-PP) of reflective cracks based on an estimation theory. Moreover, this study designs the laboratory tests to validate this estimation method of fatigue life. Then, based on the predicted fatigue life at different phases of crack progression, the sensitivity analysis is implemented to analyze the impacts of composition and knitting methods on the fatigue life. As a result, the recommendations on design and preparation of fiberglass grid are proposed. The results show that, in material composition, the glass fibers with high elastic modulus and volume fraction and the coating materials with high elastic modulus are beneficial to retarding the initiation and propagation of reflective cracks and in knitting methods, increasing density of fiber bundles parallel to the traffic direction and reducing braided angle also has positive effect. These results can be used to optimizing design and preparation of fiberglass grid to reduce the occurrence of reflective cracks in asphalt pavement. [Display omitted] • Two-scale model of fiberglass grids layer is developed. • A fatigue life estimation method is proposed for the crack initiation and propagation phases. • The material compositions and braid parameters of the fiberglass grid affect crack initiation and propagation. • The study presents recommendations for the design and preparation of fiberglass grid. [ABSTRACT FROM AUTHOR]

Fibres have been used in concrete mixtures for many applications to improve performance. Fibres bridge cracks which enhances peak, post-cracking, and toughness responses. Understanding the compressive behaviour of Fibre Reinforced Concrete (FRC) is important for the structural design of compressive members including columns, piers, and compressive struts of beams. An experimental and analytical investigation was carried out to evaluate the compressive response of FRC. A total of 50 cylinders (100 × 200 mm) were tested in compression to evaluate the effect of adding steel and/or glass fibres with three dosages (0.5%, 1.0%, and 1.5% by volume fraction) on compressive strength; modulus of elasticity; Poisson's ratio; yield, peak, and ultimate strains; and toughness index. Since adding fibres affects concrete's stress-strain relationship, a new concrete compressive stress-strain relationship that accounts for the effect of steel and glass fibres is proposed. This study also presents new design-oriented expressions for equivalent stress block parameters that consider fibre influence. Results indicate that adding fibres significantly increases peak stress, yield strain, ultimate strain, and toughness index though the modulus of elasticity was unaffected. The proposed model was found to give a good, though the conservative representation of the measured stress-strain response with experimental to predicted ratios between 1.00 and 1.13 and a coefficient of variation between 5% and 14%. • The effect of material and dosage of steel and/or glass fibres on concrete's compressive response is evaluated. • The influence of type and dosages of fibres on concrete's compressive response using statistical analyses is investigated. • The addition of steel and glass fibres considerably improves on concrete's compressive response. • A simplified compressive model based on equivalent stress blocks for FRC is presented. [ABSTRACT FROM AUTHOR]

Melia dubia is a rapidly expanding tree species in southern India, but its main drawback has been limited use in wood-based panel products until recently. To address this research gap, this study aimed to develop three reinforcement materials for producing Reinforced Laminated Veneer Lumber (RLVL) using Melia dubia. Three types of reinforcement materials, chopped glass fiber mat (CGM), glass fiber mesh (GM), and bamboo mat (BM) were employed in two layers to manufacture RLVL. The investigated parameters included physical, mechanical, and bonding performance. Furthermore, morphological images were analyzed using optical and scanning electron microscopes. The research findings revealed that the highest performance was demonstrated by BM, followed by GM and CGM. These results suggest that all three reinforcements enhanced the mechanical properties and overall performance of RLVL. Arranging the reinforcement layers closer to the surface veneer layer in the assembly resulted in outstanding mechanical properties for RLVL. The performance is superior to solid wood made from the same wood species. The findings indicate that RLVL demonstrated superior mechanical properties to laminated veneer lumber (LVL) and solid wood. The modulus of rupture for LVL reinforced with CGM, GM and BM was 7.27%, 30.91%, and 32.73% greater respectively, than that of unreinforced LVL. The composite LVL reinforced with bamboo and glass matting exhibits potential for successful utilization in outdoor structural applications, including beams, rafters, and purlins. • LVL reinforced with CGM, GM, and BM exhibited excellent modulus of rupture. • RLVL demonstrated superior mechanical properties to LVL and solid wood. • LVL reinforced with GM and BM can successfully utilized in outdoor structural applications. [ABSTRACT FROM AUTHOR]

Marl clays with varying levels of calcite content often exhibit more erratic behavior compared to other problematic soils, especially when exposed to repetitive Freeze-Thaw (F-T) cycles. It is crucial to prioritize the mechanical properties and durability of this particular soil variety as neglecting such characteristics can result in irreversible harm to the superstructures. This research focused on examining the utilization of lime and Nanoclay (NC) as stabilizers and Glass Fiber (GF) as reinforcement for natural marl soil. The study involved preparing samples with 6% lime and up to 1.5% NC, combined with varying amounts of GF ranging from 0 to 1%. The samples were cured for 7 and 28 days and subjected to 0, 1, 4, and 8 F-T cycles. Several Unconfined Compressive Strength (UCS) and Indirect Tensile Strength (ITS) tests as well as microstructural analyses including Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were performed on the samples before and after being exposed to F-T cycles. Results showed that the application of GF enhanced the UCS and ITS of lime-NC-stabilized marl soil by creating interlocking zones between the particles. The addition of lime and NC shifted the behavior of the soil sample from ductile to brittle, while the inclusion of GF caused the soil to revert to ductile behavior, resulting in a decrease in secant modulus (E 50) and an increase in energy absorption capacity (E u) compared to samples without GF. Furthermore, incorporating GF along with lime and NC into the marl soil improved the F-T durability even after 8 cycles and resulted in reduced strength deterioration compared to the control sample. The optimum mixture was found to be 6% lime, 1% NC, and 0.75% GF, resulting in a noteworthy improvement of 6.5 times in the ITS and a slight decrease of 6% after 8 F-T cycles compared to the untreated marl soil. [Display omitted] • Glass fiber enhances the freeze-thaw durability of the lime-nanoclay-stabilized marl soil. • Inclusion of glass fiber and naoclay improves the mechanical properties of marl soil. • Glass fiber changes failure behavior to ductile state even after freeze-thaw cycles. • NC particles can effectively enhance the durability of the system. [ABSTRACT FROM AUTHOR]

This study addresses the mechanical limitations of concrete fabricated with recycled brick and concrete as partial replacement of coarse aggregates, which exhibit inferior strength and stiffness compared to those with natural aggregates. To rectify this, a cost-effective approach involving low-cost glass fiber-reinforced polymer composites (LOC-GFRP) is proposed. The key parameters considered were the plain concrete compressive strength and the quantity of LOC-GFRP layers. The compressive strength of LOC-GFRP-confined concrete increased with the number of layers, with greater improvements observed in lower-strength plain concrete. Moreover, the improvement in ultimate strain was more significant than the improvement in compressive strength. The compressive strength and ultimate strain were improved by 271% and 478%, respectively. LOC-GFRP confinement resulted in a bilinear compressive stress vs. strain response, showcasing increased ductility and strength with more LOC-GFRP layers. The study evaluated various existing analytical expressions for fiber-reinforced polymers but found them inadequate in predicting parameters accurately. As a result, nonlinear regression analysis was carried out to propose expressions for predicting compressive strength and ultimate strain of LOC-GFRP-confined concrete for different aggregate types. The calculated coefficient of determination values ≥ 0.90 confirmed the good correlation among experimental and predicted values. ● Low-cost glass fiber-reinforced polymer composites (LOC-GFRP) were proposed. ● LOC-GFRP confinement resulted in bilinear compressive stress-strain responses. ● Strength and strains of LOC-GFRP-confined concrete specimens were predicted. [ABSTRACT FROM AUTHOR]

Micromechanical behavior of the interface between fiber and asphalt is a crucial factor in the performance of fiber reinforced asphalt concrete, and a thorough understanding of this behavior is essential for the design and optimization of these materials. To evaluate the micromechanical behavior of the interface, an innovative single fiber pullout test platform was designed, and the experimental parameter conditions were systematically studied. Three types of fibers including basalt fiber (BF), glass fiber (GF) and polyester fiber (PF) were adopted, and the pullout test was performed at 60 ℃, 25 ℃ and −10 ℃, respectively, where the micromechanical behavior at the interface under different experimental conditions was obtained. The results showed that the recommended loading rate of the fiber pullout test is 1–3 mm/min, and the measurement of variability is satisfactory. The single fiber pullout behavior was observed and the load-displacement curve was recorded real-time. Three failure modes (fiber pullout, fiber fracture and matrix failure) at the interface between the single fiber and asphalt mastic were observed. Furthermore, a bond-slip model which can accurately characterize the bonding-debonding behavior of the interface between the single fiber and asphalt mastic was established. It was found from the study that micromechanical behavior of the interface between the single fiber and asphalt mastic is influenced by the type of fiber and temperature, the peak load and displacement are significantly different. These findings presented in this study can play a significant role in revealing the reinforcement mechanism of fiber and providing a guidance for the efficient application and development of fiber reinforced asphalt mixture. • An innovative single fiber pullout test platform was self-designed. • The micromechanical behavior of fiber- asphalt mastic interface was investigated. • Three failure modes of the interface including fiber pullout, fiber fracture and matrix failure were observed in real time. • Bond-slip model of the interface was established based on Popovics equation. • Micromechanical behavior of the interface was greatly affected by fiber type and experimental temperature. [ABSTRACT FROM AUTHOR]

The ultimate capacity of pultruded glass fibre reinforced polymer (pGFRP) profiles depends significantly on geometrical imperfections (GIs), given their sensitivity to buckling phenomena arising from both thin walls and low elastic moduli. However, GIs are not yet comprehensively addressed in design guidance. This paper proposes a new approach to characterize the initial GIs of pGFRP profiles based on a modal approach. Given the lack of comprehensive knowledge in this area, this study presents a highly accurate and robust methodology to measure GIs and dimensional deviations (DDs) in pGFRP profiles using a 3D contact coordinate measurement machine (CMM). The modal approach encompasses the measurement of dimensional parameters and a point cloud transformation that enables the assessment of GIs associated with pure buckling modes of pGFRP profiles. This procedure allows the quantification of three types of global GIs associated to (i) minor-axis (weak axis), (ii) major-axis (strong axis) bending, and (iii) twist. Additionally, the procedure also includes the assessment of local GIs, considering the wall (plate-like) imperfections. The separation of GIs into these four types (shape and amplitude) is of major relevance as its paves the way to the development of analytical design formulas for the strength prediction of pGFRP members. The approach described in this paper also serves two important purposes: (i) the statistical analysis of DDs and GIs of pGFRP members, and (ii) the identification of distinct shapes and amplitudes of GIs that form the basis for reliable design considerations of pGFRP members. [Display omitted] • Measurement of geometric imperfections (GIs) in prismatic pGFRP profiles with automated 3D coordinate measuring machine. • Shapes and amplitudes of GIs identified with a modal approach. • Integration of GIs in FE model with damage initiation and propagation. • Towards a comprehensive dataset of GIs and reliable strength predictions. [ABSTRACT FROM AUTHOR]

The superior strength, durability, and environmental sustainability of alkali-activated slag (AAS) systems renders it a viable alternative to those based on Portland Cement (PC). However, drying shrinkage in AAS systems is a highly complex process requiring extensive testing. Several studies have reported the incorporation of fibers to AAS systems as an effective way not only to enhance its strength but also to reduce its drying shrinkage, but the information is scattered. In pursuance of this objective, the present study investigates the impact of incorporating steel, polypropylene, polyvinyl alcohol and glass fibers at varying volume fractions from 0.1% to 0.3% on both mortar and concrete AAS specimens. According to the findings, incorporating fibers to AAS concrete increased its compressive strength by up to 13% when compared to the plain mix. A higher volume fraction of 0.3% for steel and glass fiber inclusions significantly minimized the drying shrinkage of AAS concrete by 27% and 31%, respectively. However, due to the increased heterogeneity and subsequent void formation in fiber-reinforced AAS systems, it was noted that the mass loss resulting from the loss of moisture is greater in these cases. Despite the greater mass loss at earlier ages, the fibers in AAS specimens demonstrated their ability to restrain the shrinkage strains. The microstructural studies, which distinctly depict the morphology of AAS paste and the interaction between the fibers and matrix, further validate these conclusions. • Compressive strength of AAS concrete is enhanced by 13% with 0.3% steel fibers. • Glass fibers lead to maximum drying shrinkage reduction of 31% in AAS concrete. • Higher dosage of PP and PVA fibers are detrimental to drying shrinkage properties. • Increased heterogeneity in fiber-reinforced AAS systems lead to greater mass loss. • Enhanced fiber-matrix bond is evidenced with both steel and glass fibers. [ABSTRACT FROM AUTHOR]

In recent years, numerous studies have been conducted on the incorporation of plastic wastes into gypsum or plaster compounds with the aim of achieving more sustainable and environmentally friendly materials. Despite the vulnerability of plastic materials to high temperatures, it is not common to analyze the behavior of these new compounds in case of a fire. In this study, different lightweight plaster compounds have been developed, partially replacing the original raw materials with plastic waste in dissolution up to 23.5% and reinforced with glass and basalt fibers. After exposing the compounds to real direct fire, mechanical characterization (flexural strength, compressive strength, surface hardness tests) and physicochemical characterization (XRD, TGA) have been carried out, including the calculation of CO and CO 2 emissions associated with the combustion of the compounds, as well as imaging by scanning electron microscopy. The results show that the reduction in the density (between 15%−24%) of the new compounds favored lower temperatures during exposure to flames, preventing material cracking. Likewise, the new composites experienced a loss in flexural strength between 44%− 51%, and a drop in compressive strength between 2%− 63%, being these losses in strength lower than those experienced by the reference composites. The addition of glass fibers demonstrated to confer better flexural behaviour to the compounds with added waste, while the basalt fibers were more efficient in compression. Furthermore, the estimated toxic emissions produced during the combustion of the designed compounds did not exceed the immediately dangerous to life or health (IDLH) values established by the Material Safety Data Sheet (MSDS), remaining below 2000 ppm/h for CO and 40,000 ppm for CO 2. This study contributes to a better understanding of the behavior of plaster compounds with incorporation of plastic waste in case of fire, highlighting the developed materials as a viable alternative for the production of more environmentally friendly prefabricated products. • The sustainable plaster composites developed lead to a 23% reduction in raw materials. • Composites with the dissolved residue obtained higher mechanical strengths after fire. • The dissolved residue addition increased strength provided by basalt fibre around 60%. • CO and CO 2 emissions associated to composite combustion did not exceed the limits. [ABSTRACT FROM AUTHOR]

To address the deficiencies in traditional communication towers in mobile communication engineering, such as heavy weight, easy corrosion and poor durability, this study proposes replacing traditional communication towers with GFRP communication lattice towers with lightweight, high-strength and good durability. Firstly, GFRP material test and GFRP circle tube bending capacity test are conducted. The maximum bending moment that can be subjected to the anchorage end of GFRP circular tube is 18.20 kN·m. Finite element analysis of GFRP circular tubes verifies the accuracy of the bending test results. Secondly, a GFRP communication lattice tower with a height of 25 m is designed adopting GFRP circular tubes as tower columns. Through the bending test of the GFRP tower, it is verified that the connection between the columns and web members of the GFRP tower is reliable and the force pattern of the GFRP tower is reasonable. The large deflection theory can be adopted to the displacement of GFRP towers accurately. Thirdly, according to the actual engineering requirements, the finite element analysis of 25 m-high GFRP tower under the basic wind pressure of 0.45 kN/m2 is carried out by using 3D3S (a spatial structure design software). It can be obtained that the vibration mode of the GFRP communication tower shows two forms of lateral bending and axial torsion. 0° wind load direction has the greatest influence on the displacement of the GFRP tower. The stress ratio of each component in the GFRP tower is less than 1, indicating that no damage occurs in the GFRP tower. Finally, GFRP towers have good economic benefits, good environmental performance and wide range of application after comparing the GFRP tower and traditional steel tower. The demonstration project of the GFRP communication lattice tower is established in Qingyuan City, Guangdong Province, China. When subjected to a typhoon with a wind speed of 17.26 m/s, The horizontal displacement of the GFRP tower top is 10 m, which is about 2/5 of the height of GFRP tower. Although the displacement is large, the GFRP tower is still not destroyed. It can be concluded from the research in this paper that GFRP towers have low cost, good mechanical properties, good durability, and wide application range, which can promote the rapid construction of 5 G communication base stations. [Display omitted] • The bending moment of the GFRP tube can reach 18.20 kN·m. The finite element analysis match well with bending test. • A 25-m-high GFRP lattice tower is designed. The deformation of GFRP tower can be calculated by large deflection theory. • The vibration mode of the GFRP tower shows two deformation forms: lateral bending and axial torsion around the z-axis. • The GFRP tower has a large displacement but no damage, when subjected wind with the speed of 17.26 m/s. • Applying GFRP tower can effectively improve the construction efficiency of 5 G communication base station. [ABSTRACT FROM AUTHOR]

• The compressive strengths of SCC are mutually influenced by nanosilica content and glass-fiberfiber volumetric fractions. • Increases in NS content between 0% and 4% result in increases in compressive strengths. • The use of NS and GF provided an excellent enhancement in the static elastic modulus of SCC compared to those free of nS and GF. • The flexural strength increased with increasing GF volume fraction. • The added GF also improved the gas-permeability properties of each affected SCC mixture. This article studied the influence of utilizing nanosilica (NS) and glass fiber (GF) on mechanical and permeability properties of self-compacting concrete (SCC) with fly-ash blended. There were three SCC series designed. This study had a constant amount of water-to-binder (w/b) ratio and total binder content which is 0.35 and 550 kg/m3, respectively. This study utilized three different percentages of nanosilica to replace cement. These percentages were 0%, 2%, and 4% by weight, respectively. The incorporation of fly ash (FA) was done by using 25% of total binder content by weight in all the SCC mixtures. Moreover, glass fiber was used as an additive material with levels of 0%, 0.35%, 0.70%, 1.0%, and 1.5%, respectively. To experimentally evaluate mechanical properties; compressive strength; static modulus of elasticity; splitting tensile strength; fracture energy, and the permeability properties of the mixtures; sorptivity index; rapid chloride permeability test (RCPT); gas permeability test were done. The results showed that with utilizing nanosilica which ranged from 0% to 4% with replacement up until 0.7% glass fiber, indicated to enhance the mechanical and permeability properties of self-compacting concrete. [ABSTRACT FROM AUTHOR]

• Mechanical properties and contribution of pozzolans in GFRC strength were studied. • The two premix and spray-up method were employed to manufacture GFRC. • AR Glass fibers with three different types of pozzolanic materials were used. • Toughness index and modulus of rupture were declined over time due to aging. • Application of metakaolin lead to the highest value of mechanical properties in GFRC. Glass fibers have shown to improve the mechanical properties of concrete as tensile strength and flexural strength. However, it has been shown that these fibers tend to corrode with concrete aging to affect glass fiber reinforced concrete (GFRC) properties in an adverse manner. To prevent glass fiber corrosion in concrete environment, different percentages of pozzolanic materials were used in this study. It was found that the glass fibers inclusion would lead to partial reduction in concrete compressive strength. Modulus of rupture and toughness index were observed to improve greatly as a result of reinforcing concrete with glass fibers. Moreover, inclusion of nanosilica and metakaolin was found to prevent declines in concrete toughness and modulus of rupture with aging. Investigation of the pozzolanic contribution to modulus of rupture in GFRC revealed that the specific strength of cement declined within 7–90 days. This is while the specific strength of pozzolanic effect increased with time. [ABSTRACT FROM AUTHOR]

• Strength and toughness of fiber reinforced cemented tailings backfill (CTB) were studied. • Polypropylene, polyacrylonitrile and glass fibers were used in CTB as fiber reinforcement agent. • Strength gain of fiber-reinforced CTB showed an increasing trend as the fiber content rises. • Addition of different types of fibers caused a significant change in CTB's toughness. • The crack resistance of fiber-reinforced CTB was remarkably better than that of unreinforced ones. In this paper, an experimental investigation was carried out to study strength, toughness and microstructural properties of early age cemented tailings backfill (CTB) reinforced with three different types of fiber. Polypropylene, polyacrylonitrile and glass fibers were used in CTB to better understand the effect of fiber addition on the backfill's strength and toughness properties. Different fiber contents (0 wt%, 0.3 wt%, 0.6 wt% and 0.9 wt%) and curing times (3 and 7 days) were designed for the preparation of CTB samples with two cement-to-tailings ratios (c / t = 1:4 and 1:6). The results indicated that the addition of different type and content of fibers caused a significant change in CTB's toughness. The fiber content influenced the backfill's strength performance. The strength gain of fiber-reinforced CTB samples showed an increasing trend as the fiber content rises. Linear relationships could be used to express relations between strength gain and fiber content. The peak strain factor K was defined during the toughness tests. K showed a monotonous increasing trend by the increase of fiber content. The polypropylene fiber was larger than polyacrylonitrile, but less than glass fiber when fiber content was 0.3 wt%. The unreinforced CTB samples were mainly parallel to the axial tensile cracks and a small amount of shear cracks, while the deformation of fiber-reinforced CTB was relatively large, it did not break into small pieces. The crack resistance of fiber-reinforced specimens was notably better than that of unreinforced ones. Failure mechanism and modes of fiber addition in CTB samples were also studied. As a result, this study could provide a theoretical/application basis for mines to reduce cement usage within the CTB matrix, achieve safe mine production, increase ore extraction and reduce ore losses and dilution. [ABSTRACT FROM AUTHOR]

• Influence of aggressive marine environments on durability and confinement efficiency of FRP-confined concretes is investigated. • Degradation in mechanical properties of FRP sheets and FRP-confined concretes is found in aggressive marine environments. • The strain efficiency factor can be as a function of environmental condition. In order to find effective confining pressure in concrete members externally wrapped with Fiber Reinforced Polymer (FRP) jackets, different values of the so-called strain efficiency factor have been suggested by several researchers. In this paper, the durability of Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) sheets in aggressive marine environment is assessed, and the effect of such environments on the strain efficiency factor in compressive members is investigated. A set of 3D finite element analyses (FEA) are performed to find the strain efficiency factor. The strain efficiency factor of GFRP jackets is lower than that of CFRP jackets in different environmental conditions. Furthermore, the strain efficiency factor decreases as the exposure time increases, which is more evident in GFRP-wrapped concrete. After 3000 and 9000 h of marine exposure, the strain efficiency factors decrease by 11% and 43%, respectively, in GFRP jackets. In CFRP-wrapped members, the reduction is about 18% and 25%, respectively. [ABSTRACT FROM AUTHOR]

• The effect of stiff slender elements on shear performance of reinforced concrete beams was studied. • The elements were made with glass fiber reinforced polymer (GFRP) composite materials. • The stiffest elements (needles) improved the shear performance of concrete significantly. • Further studies are needed to optimize the geometry and mechanical properties of needles. The present work investigates the shear performance of concrete beams reinforced longitudinally with steel rebars incorporating randomly distributed stiff elements known as "needles". Compared to commonly used fibers, needles function differently in concrete members that carry increasing internal stresses. To measure the effect of needles on the mechanical performance of concrete, 32 longitudinally reinforced concrete (RC) beams and 96 non-reinforced concrete prisms were tested. Among numerous possibilities, the dimensions of the needles used in the present study were selected based on a number of practical considerations. The results showed that the needles increased the peak and residual shear capacity of the reinforced beams significantly. However, the improvements were not greater than those achieved by using the same volumetric content of fibers made of the same material as that the needles were produced from. Based on the measured results and the observation of cracking patterns, guidance for optimizing the geometry of needles and test specimens are provided for future research. [ABSTRACT FROM AUTHOR]

• Adobes performance was improved when using GFRP waste. • Decrease of cracks and smaller linear shrinkage when stabilized with GFRP waste. • Significantly smaller mass loss and regularity of edges when submerged in water. • Thermal conductivity decreases up to 21% using GFRP residue. • Compressive strength increased up to 45% with GFRP waste. The polymer industry develops materials with excellent physical and mechanical properties but also with a large volume of waste with very low degradability. Therefore, the objective of this paper was to use glass fiber reinforced polymer (GFRP) waste in adobe production. Compositions varying from 0 to 10% mass residues were produced and evaluated in physical, mechanical and thermal tests. The addition of 10% GFRP waste showed the best results when compared to adobe without additives, demonstrated as follows: shrinkage reduction of 239%; bulk density reduction of 6%; thermal conductivity reduction of 21%; mass loss reduction when submerged in water; and compressive strength increase of 45%. Therefore, the use of GFRP residue is indicated in the manufacture of adobe to improve its physical, mechanical and thermal conductivity properties. In addition to providing a destination for a considerable quantity of the waste, the commercial value of the final product is higher due to using a residue with low degradability and high energy power due to burning during recycling. [ABSTRACT FROM AUTHOR]

• Nano-Al 2 O 3 enhanced nanocomposites reduce the water diffusion coefficient by 17 %. • It improves the interlaminar shear strength by11% and flexural strength by 13%. • The glass transition temperature of the nanocomposites has not improved significantly. • Nano-Al 2 O 3 embedded nanocomposites create the opportunity to be used in seawater environment. Retention of mechanical and thermal properties of nano-Al 2 O 3 embedded glass fiber reinforced polymer (GFRP) composites in marine environment is necessary and need to be evaluated to realize the full potential of the nanocomposites. The plain and nanocomposites were seawater aged in a temperature controlled seawater bath at 70 °C for a duration of 40 days. The results revealed that seawater aged plain and nanocomposites deteriorate their flexural strength, interlaminar shear strength and glass transition temperature. However, with the addition of 0.1 wt% of nano-Al 2 O 3 particles into the plain GFRP composite, the flexural strength increased by 12%, interlaminar shear strength by 11% in dry condition and seawater diffusion coefficient was reduced by 17% as compared to plain GFRP composites. Nevertheless, the glass transition temperature of the nanocomposites was not improved in dry and seawater aged conditions significantly. The fractured surfaces of tested samples were investigated through FESEM to support the new findings. [ABSTRACT FROM AUTHOR]

• Brickwork cavity walls are very vulnerable to seismic loading. • This paper analyses a new retrofitting method based on the use of FRCM coating and GFRP ties. • GFRP rods were used to reinforce the masonry walls against in-plane and out-of-plane actions. • Reinforced structures presented enhanced behavior and increased mechanical properties. This paper offers the results of an experimental investigation aimed at assessing the seismic vulnerability of a type of cavity wall, with a brief discussion of the advantages of this form of construction. Cavity walls were mainly designed to carry vertical loads and to improve the thermal behaviour of the building envelope: these are made of two single-wythe walls (typically using low-perforated bricks) with a cavity filled with a polystyrene panel. Cavity walls often exhibit poor seismic performance. A total of 12 full-size cavity-wall panels were tested in this experimental programme at the laboratory, by conducting shear and bending tests aimed at studying the in-plane and out-of-plane structural responses under simulated seismic actions. In addition, different retrofit solutions were studied and used to reinforce the cavity-wall panels: this included the traditional method to tie the wall leaves with steel connectors, an innovative method made of GFRP (Glass Fiber Reinforced Polymers) rods, and a mortar coating reinforced with a composite grid, known as FRCM (Fiber Reinforced Cementitious Matrix). It was found that the lateral bending-capacity of the panels reinforced with the GFRP rods and a FRCM coating greatly increased over that of the control unreinforced specimens. The proposed reinforced method was able to provide some seismic resisting capacity to the cavity walls, especially against bending and out-of-plane loading, in a more effective way than the traditional method of steel ties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alkali-activated slurry infiltrated fiber concretes (SIFCON) were produced with ground granulated blast furnace slag (GGBS). • Waste glass was reutilized as a silicate source in the activation of GGBS. • Waste steel fibers recovered from scrap tires were used in the SIFCON production. • Thus, the mixtures produced are primarily composed of waste materials or by-products. • Flexural strength, splitting tensile strength and fracture energies increased with the fiber content. • Mechanical properties of the alkali-activated SIFCON containing waste fibers were similar or better than those of the reference mixtures. This experimental study focuses on sustainable slurry infiltrated fiber concretes (SIFCONs) by utilizing alkali-activated ground granulated blast furnace slag (GGBS) and waste fibers. The waste fibers were high-strength steel fibers recovered from scrap tires. Additionally, waste glass was employed as a substitute for commercial sodium silicate activator, contributing to the reutilization of a waste material. Such an approach stands out for its use of various waste materials to achieve a high-performance concrete primarily composed of recycled materials. Literature survey indicate that there are no studies available on concrete primarily composed of waste or recycled materials. In this study, the molarities of the activators were selected as 8 M and 14 M based on a prior research. Due to the fiber geometry and the associated bulking effect, a maximum waste fiber content of 5 % was adopted, with increments of 1 %. Load–deflection curves of the specimens were obtained in the bending test. Various mechanical properties, including compressive strength, splitting tensile strength, flexural strength, and fracture energy, were determined for the mixtures. The mechanical properties of the alkali-activated mixtures were improved compared to those of the reference concretes. Based on the mixture proportions and materials employed, alkali-activated mixtures in the study achieved compressive strengths exceeding 120 MPa and flexural strengths approaching 30 MPa. Furthermore, significant enhancements in fracture energies were observed. The strengths of the mixtures with waste glass, however, were lower compared to the other mixtures. Nonetheless, in summary, the study shows the promising potential of waste steel fibers and waste glass for the production of alkali-activated slag SIFCON. This approach not only enhances cost-effectiveness, sustainability, and mechanical properties but also reflects a significant step towards achieving a concrete composition that relies solely on waste materials. [ABSTRACT FROM AUTHOR]

• A sprayed ultra-high-performance concrete (SUHPC) using glass fibres was developed. • Spraying increases the mechanical performance, achieving compressive strengths up to 144.0 MPa. • 2 vol.% fibres result in maximum optimal mechanical performance with minimal impact on durability and permeability. • Geometric stability is successful for mix designs with high fibre contents. Sprayed concrete relies on the presence of an accelerator to set rapidly in place and achieve adequate geometric stability. This significantly reduces its strength, workability, and limits its application to specialised projects whereby the technical advantages of spraying outweigh the limitations rendering it more suitable over conventional placing methods. This study proposes the development of a novel sprayed ultra-high-performance concrete (SUHPC), suited for the application of complex shaped structures, utilising high glass fibre content and thin section requirements to achieve geometric stability. The study assesses the effects of fibre content on the mechanical, permeability, and durability performance of the developed SUHPC, and provides an assessment of its feasibility for spraying complex shaped free form architectural structures. The study found that incorporating high fibre contents in excess of 2 vol% allowed the mix to maintain geometric stability, while attaining ultra-high compressive strengths of up to 144 MPa. Meanwhile the durability and permeability performance remained above the typical threshold for typical UHPC. This study allows the revitalisation of UHPC for sprayed applications, incorporating an all-in-one architectural and structural design solution. [ABSTRACT FROM AUTHOR]

[Display omitted] • The current study evaluates the fracture energy of HMA when basalt and glass fibers are used. • The fracture energy of the mixtures was determined via the SCB test method. • The effect of the basalt and glass fibers on the fracture energy of HMA was compared. • The maximum fracture energy was attained from the groups with a 0.50% basalt fiber rate. This paper has focused on the effect of basalt and glass fibers in HMA in terms of crack formation and damage mechanisms. The experimental study was carried out under two stages; i) defining optimum fiber lengths and rates based on Marshall Stability performances using three different fiber lengths (4 mm, 12.5 mm, 22.5 mm) and three different fiber rates (0.75%, 1.00% and 1.5% by weight), ii) examining of fracture tests by using the optimum fiber values (4 mm fiber length and 0.50%, 0.75%, 1.00% fiber content by weight) obtained from the first stage. Fracture energy characteristics of HMA mixtures were examined via Semi-Circular Bending (SCB) test. A total of 24 SCB test specimens from 6 different series, B-0.50, B-0.75, B-1.00, G-0.50, G-0.75, and G-1.00, were used in the experiments. Experimental results were discussed based on some basic physical properties, fracture energy (Gf), dissipated energy (DE), flexibility index (FI), and crack resistance index (CRI) values of HMA mixtures. When 0.50% basalt fiber is utilized in asphalt mixtures, the maximum peak load and Gf value are achieved. Moreover, using 1.00% basalt and 0.75% glass fiber in asphalt mixtures yielded the highest values of FI and CRI, respectively. Nevertheless, when 1.00% glass and 0.75% basalt fiber were added to asphalt mixtures, the minimum values of FI and CRI were obtained, respectively. [ABSTRACT FROM AUTHOR]

• The effect of AR-GF dosage and its hybrid mode on the mechanical and microscopic properties of AR-GFRS is investigated. • HP significantly improves the splitting tensile strength of AR-GFRS. • The hybridization of HP and HD enhanced the compressive strength of AR-GFRS at an early age. • The reinforcement mechanism of mixed AR-GF on shotcrete was investigated based on the macro–micro test results. Fiber reinforced shotcrete (FRS) is an essential method for engineering support such as tunnels, slopes, and foundation pits. This study focuses on addressing the limitations of traditional fiber-reinforced shotcrete (FRS) by introducing innovative alkali-resistant glass fiber (AR-GF) series products, namely Anti-Crak® HP (HP) and Anti-Crak® HD (HD) mixed FRS. The aim is to overcome issues such as rusting, corrosion, high labor, and low surface aesthetics. The mechanical and microscopic properties of alkali-resistant glass fiber reinforced shotcrete (AR-GFRS) were investigated under different conditions of admixture and mixing patterns using uniaxial compression, split tensile, and scanning electron microscopy (SEM) tests. The results show that the mixing of AR-GF series products HD and HP greatly enhanced the mechanical properties of shotcrete and improved the microstructure of shotcrete. The split tensile strength was increased by 23% with the 6% content compared to 3% with HP fiber alone. AR-GFRS in HP and HD hybrid mode has better compressive and splitting tensile strength compared with the same total content of AR-GF with HP fibers alone. The optimal amount of HP was 3% of the cement mass for single mixing of HP, and the optimal mixing pattern of HP and HD was the mixing of HP (length 24 mm) and HD (length 18 mm and 6 mm). The excellent integrity of the rupture surface can be observed from a microscopic point of view, and the AR-GF was predominantly extracted. The HP damage morphology on the rupture surface was classified into fiber integrity, breakage, disorganization, and dispersion. A hybrid AR-GFRS model was established to reveal the hybrid AR-GF shotcrete reinforcement mechanism. The research results provide new ideas for the development of mixed fiber shotcrete, and lay the foundation for the design and construction of mixed alkali-resistant glass fiber shotcrete support. [ABSTRACT FROM AUTHOR]

• A novel FRP family with high stiffness and ductility was developed. • Tensile behavior and damage mode of glass/PP composites was evaluated. • The delamination was the sole appropriate failure mode for glass/PP composites. • A two-limit tensile constitutive model for glass/PP composites was developed. Traditional interlayer fiber reinforced polymer (FRP) composites utilized in civil engineering are deficient in either the sufficient stiffness or ductility. For this, a study was conducted on the tensile behavior of interlayer hybrid FRP composites, which were composed of polypropylene (PP) and glass fabrics with an epoxy resin as the matrix and a central layer of glass fabric. This paper presents the design concept, failure mode, and constitutive model for glass/PP FRP composites. The experimental results indicate that the glass/PP FRP composites exhibit higher stiffness and ductile compared to traditional FRP composites, thereby demonstrating superior mechanical properties. Moreover, the finite element (FE) method was employed to identify all potential failure modes of glass/PP FRP composites, and it was concluded that only delamination failure mode is applicable in civil engineering. Based on the FE results, a failure mode map was generated for glass/PP FRP composites, which can facilitate rapid identification of its failure modes. To quantify the tensile behavior of these composites, a two-limit tensile constitutive model was developed. Considering that composites are typically designed for tension, the research presented in this paper can offer theoretical support for the implementation of glass/PP composites in civil engineering applications. [ABSTRACT FROM AUTHOR]

• A novel structural form of elliptical rubber concrete filled double-skin GFRP tubes (CFDSTs). • Axial compressive test on elliptical CFDSTs. • Effects of void ratio and rubber content on the structural behavior of CFDSTs. • Proposal of predictive formulas for the capacity of CFDSTs. This study proposed a double-skin section consisted of an elliptical glass fiber reinforced polymer (GFRP) outer tube, a circular steel inner tube and rubber concrete filled between them, which had the features of aesthetic appeal, structural efficiency and waste recycle. Axial compressive test was conducted on the elliptical rubber concrete filled double-skin GFRP tubular (CFDST) short columns with various void ratios and rubber contents. Load-axial strain-hoop strain data was obtained from the experiments and the contribution of each component (i.e., concrete, GFRP tube, steel tube) to resist the applied load was clarified. Experimental results indicated that the void ratio and rubber content had the most significant effects on the dilation property (i.e., hoop and axial strains) and confinement effect of the rubber concrete. Nevertheless, effects of steel tube thickness and rubber particle size were insignificant. Based on the experimental results and confining concrete theories, a theoretical model, with proper considerations on the effects of void ratio, rubber content and aspect ratio, was proposed to estimate the ultimate load-carrying capacity and ultimate strain of the stub columns under axial compression. Finally, reasonability and accuracy of the proposed model were verified by the experimental results. [ABSTRACT FROM AUTHOR]

• Thermal/fire resistance of glass fiber reinforced geopolymer composites is studied. • Variation in composite panel thicknesses has negligible effect on fire resistance. • ∼25–30% of flexural strength of the panels is retained even after fire test. • Phase evolution and structural changes of panels with temperature is studied. With a specific emphasis on understanding the thermal and fire resistance, in this work, sodium- and potassium-type metakaolin geopolymers (with Si:Al > 2) reinforced with glass fiber (GF) fabrics were manufactured. X-ray diffraction and solid-state nuclear magnetic resonance spectroscopy were used to understand the changes in structure and evolution of phases with temperature. The geopolymer matrices have shown stability up to 700 °C, above which a fiber–matrix interaction was detected before they crystallized into different phases at 1000 °C. The fire resistance times of these panels (12–17 mm thick) when a temperature profile similar to ISO 834 fire curve was imposed were 53.6–55.1 min for Na-GF and 53.2–68.7 min for K-GF composites. Further, one-dimensional thermal analysis using cone calorimeter has suggested the initiation of cracking through the matrix during dehydration because of stress relief. This had an influence on the fire resistance timing of the panels. Despite this, both composites still retained ∼25–30% of their initial flexural strength after the furnace test, which was understood as a compromise between the variations of formed phases and morphological features in the exposed and unexposed sides. [ABSTRACT FROM AUTHOR]