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High-Performance Concrete (HPC) is characterized by its densely structured microstructure, providing superior strength and impermeability compared to conventional concretes, but it remains susceptible to spalling when exposed to high temperatures. To address this limitation, the present study focuses on the formulation of High-Performance Lightweight Concrete (HPLC) by incorporating sisal fiber and steel fiber, aiming to mitigate the tendency for spalling under elevated thermal conditions commonly observed in HPC. The present research employed the Modified Andreasen & Andersen particle packing model to optimize the initial mixture proportions for HPLC. This study comprehensively examined the effects of varying sisal fiber concentrations on the workability, mechanical properties, durability, microstructure, and thermal spalling of HPLC. Key findings from the experimental investigation indicate that HPLC developed in this study exhibits high compressive strength, with the most notable performance observed at a sisal fiber volume of 2.0 %, resulting in an apparent density of 1876 kg/m³ and a compressive strength of 110.1 MPa. Incorporation of sisal fiber at a volume of 1.0 % significantly enhances the mechanical properties of HPLC, as evidenced by increases of 11.6 % in flexural strength, 11.9 % in compressive strength, 6.5 % in elastic modulus, and 25.8 % in impact resistance. Additionally, at the same fiber inclusion rate, improvements are noted in the material's resistance to chloride ion penetration and drying shrinkage, with reductions of 4.9 % and 7.3 %, respectively. Adequate amounts of sisal fiber also improve the gel pore structure of HPLC matrix. The thermal degradation of sisal fibers at high temperatures creates channels for steam egress, reducing vapor pressure within HPLC and thereby enhancing its resistance to thermal spalling. A holistic examination of the influence of sisal fibers on the mechanical performance, micromorphology, and thermal endurance of HPLC indicates that the optimal sisal fiber content is established at 1.0 % by volume. Future research could concentrate on optimizing fiber types and compositions, exploring hybrid fiber options, and evaluating long-term durability under diverse environmental stresses to broaden the scope of applications. • Mixture of HPLC was designed via MAA particle packing model. • Thermal and mechanical properties of HPLC were improved via sisal fiber. • Pore structure of HPLC was improved by sisal fiber. • Drying shrinkage and chloride migration coefficient of HPLC were reduced via sisal fiber. • Optimal amount of sisal fiber in HPLC was 1.0 vol%. [ABSTRACT FROM AUTHOR]

The current rate of expansion in construction activities, especially for new infrastructure or retrofitting and strengthening of existing structures, calls for a large volume of traditional materials, which consume extensive energy and generate a significant amount of carbon. In order to tackle this issue, efforts are being made to explore bio-based materials, such as natural fibers and bio-polymers-based composites. In order to boost the functionality and performance of natural fiber-reinforced polymer composites (NFRPC), gamma-ray irradiation was incorporated as a post-processing technique because it is a time-effective and pollution-free physical treatment to improve the performance of sustainable composites. In the current experimental investigation, sustainable materials such as sisal fiber (SF) (30 wt%) and biobased poly (butylene succinate) (bio-PBS) (70 wt%) were used to fabricate the biocomposites. The developed composites were exposed under gamma (γ) irradiation at different doses, such as 5, 10, and 15 kGy. Thereafter, the mechanical, thermal, and microstructural properties, as well as the crystallinity and water absorption behavior of irradiated composites, were compared with unirradiated composites. At 15 kGy of radiation dose, the tensile and flexural strength values were considerably greater than those of unirradiated specimens. From these experimental results, it can be concluded that the composites, which were exposed to 15 kGy of radiation dose, showed the optimum values compared to their counterparts. It has been observed that for semi-structural construction, military, automobile, and non-structural, as well as packaging applications, sisal fibers are the most favorable substitutes for synthetic fibers. [Display omitted] • Extrusion and injection molding processes were optimized to develop composites. • The effect of γ-ray irradiation was investigated on the performance of composites. • Tensile strength and crystallinity of composites increased post-treatment. • Water absorption percentage in gamma irradiated composites reduced. • Cross-linking and lesser hydroxyl groups post irradiation improved properties. [ABSTRACT FROM AUTHOR]

Reinforcement of cement-based systems is one of the main unsolved issues for 3D printing technology (3DP). The use of short fibers is a promising way to improve cement-based systems fresh and hardened strength, overcoming this limitation. Among natural fibers, Sisal fibers (SF) can be an excellent option, due to their irregular cross-section morphology, water retention capacity and high Young modulus. In this study, fresh and hardened properties of 3D printable cement-limestone filler mortar reinforced with 1 % volumetric fraction (VF) of 6.5 mm SF and 0.5, 1 and 1.5 % VF of 13 mm SF was assessed. Fresh state mortar rheology was evaluated using flow table test (FT), Self-weight cone-penetration (WCP), Displacement-controlled cone-penetration (DCP) and fresh squeeze tests (SQT). 3DP was evaluated on mortars using a manual extruder and a 3D cartesian robotic printer. Hardened physical and mechanical properties were tested, comparing the effect of 3DP and SF reinforcement on conventional and 3D printed specimens. It was observed that SF slightly modified mortars' rheology and cohesiveness, while SF improved fresh mechanical behavior and enhanced flexural strength and toughness index (I T) on hardened state, due to SF alignment produced by 3DP. Water capillarity and open porosity was also modified by 3DP, due to particle squeezing and fiber´s alignment during extrusion. Higher VF and longer fibers reduced robotic printability and produced discontinuities and pumping blockage, showing limits for SF addition. • Sisal fiber (SF) of 13 and 6.5 mm length were added to 3D printable mortars. • SF increased shear yield stress and mechanical properties in fresh state. • Ram and screw system 3D printing methods were used and in both SF were aligned. • SF and 3D printing process increase apparent density and reduce open porosity. • Aligned SF increased flexural strength and toughness index of 3D printable mortars. [ABSTRACT FROM AUTHOR]

The substantial use of fly ash as cement replacement to reduce carbon emissions is identified as the primary goal, 50 % of the cement was substituted with fly ash and in order to avoid the low early stage mechanical properties of the composite, varying doses of sodium sulfate were used as an activator of fly ash. Additionally, sisal fibers were chosen to enhance the flexural strength. The results indicate that sodium sulfate significantly enhances the early stage mechanical performance of the cementitious composites and the matrix exhibits the optimal mechanical performance at 4 wt% sodium sulfate dosage (4SS). The addition of sisal fibers resulted in an enhancement of the flexural performance of the material. The collaboration between sodium sulfate and sisal fibers results in an improvement in the initial flexural performance of the material while preserving its compressive strength. The single-fiber pullout test further confirmed that adding sodium sulfate enhances the fiber-matrix interface and bonding. Microstructural investigations by XRD, TGA, MIP, and SEM-EDS revealed accelerated hydration and early formation of a large amount of ettringite due to the addition of sodium sulfate. Ettringite acts as a gel nucleation seed, promoting the formation of a dense gel structure and effectively improving the early mechanical properties of the composite. Furthermore, with curing age, sodium sulfate also effectively improves the pore structure of the matrix in the late hydration stage. • Sisal fiber-reinforced fly ash cement mortars were activated by sodium sulfate. • Fiber-matrix interface & bonding at varying sodium sulfate dosages were evaluated. • Mechanical and microstructural properties of composites were studied. • Performance enhancement mechanism was studied by XRD, TG, MIP, & SEM-EDS. • Sisal fibers & FA increase materials performance and reduce carbon emissions. [ABSTRACT FROM AUTHOR]

Compressed stabilized earth blocks (CSEB) represent an eco-friendly substitute for traditional building materials, predominantly utilizing earth. Municipal Solid Waste Incineration Bottom Ash (MSWIBA) is a by-product of municipal waste treatment that can be creatively repurposed in construction projects. This research explores integrating MSWIBA as a substitute for Earth in CSEB production to conserve natural resources and repurpose waste, potentially reducing its landfill disposal. The sisal fibers (SF), often regarded as by-products of agricultural processes, offer an intriguing research material. The SF was treated with a 5 % NaOH alkaline solution to improve the CSEB bonding, increasing the flexural strength. The study aims to determine the optimal mix of stabilizers, in addition to a 10 % cement content, using various percentages of MSWIBA (10–40 % by weight of dry sand) and SF content (0.25–1 % by weight of dry soil). These blocks undergo comprehensive tests to determine their strength and durability. Wet and dry compression, flexural tests and indirect tensile tests were used to assess strength qualities, while wetting-drying cycles and acid exposure were used to determine durability. MSWIBA replaces 20 % sand in CSEB satisfying the strength. However, exceeding this amount increases void content and lowers strength, emphasizing the importance of balanced proportions for best performance. The 20 % MSWIBA and 0.75 % SF combination enhanced the compressive strength by 6.45 MPa, flexural strength by 0.92 MPa and water absorption by less than 18 %. The durability test displayed increases in compressive strength of 14.7 % and flexural strength of 93.48 % and optimized water absorption rate. Furthermore, microstructural analysis has been performed on CSEBs and the results highlight the importance of balanced cement and SF proportions for structural integrity. Life Cycle Analysis (LCA) investigation shows that construction costs using CSEB are 12.24 % higher than those with FCBs. Additionally, the study suggests that CSEB with MSWIBA and SF will be an environmentally sustainable construction material, considering factors such as energy usage, Global Warming Potential, and other environmental considerations • MSWIBA and sisal fiber has been assessed to produce strong and durable CSEBs. • Inclusion of MSWIBA 20 % with 0.75 % sisal fiber satisfies the strength requirements. • Acid attack and Wetting & drying test were performed for durability analysis. • The environmental and economic viability of CSEB was demonstrated through life cycle analysis. • Life cycle analysis proves that CSEBs outperform traditional burnt clay bricks. [ABSTRACT FROM AUTHOR]

An alkali treatment is necessary for natural plant fibers employed as reinforcing additives in inorganic cementitious materials, aiming to diminish moisture sensitivity and facilitate interlocking between the matrix and additives. Recycling alkali-treated fiber wastewaters (ATFWs) is crucial to prevent significant environmental pollution. Sisal fiber (SF)-reinforced alkali-activated slag-based composites incorporating ATFWs were prepared and compared to the control, aiming to investigate the effects of alkali-treated SFs and recycled ATFWs on the long-term mechanical properties and microstructures. Initially, the influence of the treated duration of SFs was examined on the electrical conductivity (EC) of ATFWs. Subsequently, the effects of SFs and ATFWs on the 28-day and 360-day flexural and compressive strengths were investigated, including an observation of failure modes. Furthermore, the effect mechanism of ATFWs in SF-reinforced composites was detected concerning morphology, microstructure, and composition by using diverse analytical techniques such as Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Thermogravimetric-Differential Scanning Calorimetry (TG-DSC). The results show that the inclusion of ATFWs diminishes electrical conductivity (EC) and density while augmenting the flexural and compressive strengths of the composites. When extending the treatment duration of SFs in a 10% NaOH solution from 1 hour to 3 hours for SF-reinforced composites, the 360-day flexural and compressive strengths for samples without SFs show an enhancement of 1.1 times and 0.9 times, those with 1% SFs exhibit an increase of 0.7 times and 0.5 times, and those with 2% SFs demonstrate an improvement of 0.3 times and 0.4 times, respectively. Furthermore, the incorporation of ATFWs enables the physical embedding and sequestration of organic components released from SFs in a matrix without local aggregation. Therefore, recycling ATFWs as an alkaline activator is deemed feasible to produce SF-reinforced SP-based composites. The research outcomes offer an innovative approach for whole-waste utilization in the realm of natural fiber-reinforced composites. • Recycling alkali-treated fiber wastewaters (ATFWs) in sisal fiber-reinforced composites shows a sustainable approach. • ATFWs reduce density while enhancing long-term flexural and compressive strengths in the composites. • ATFWs enable physical embedding of organic components in a matrix, avoiding local aggregation. • Organic components in ATFWs undergo biodegradation in an alkaline matrix with increasing curing age. [ABSTRACT FROM AUTHOR]

• Characterization of innovative FRCM with natural fibers is performed. • Sisal-NFRCM performances are investigated through tensile and shear tests. • Dispositions of the Round Robin Tests RILEM Technical Committee 250-CSM are adopted. • Tensile tests evidenced an appreciable tension stiffening effect. • Single-lap shear tests evidenced the failure of the yarns with progressive slippage. The experimental characterization of a Natural Fiber Reinforced Cementitious Matrix (NFRCM), made of sisal fibers yarns impregnated with a water-based resin and embedded in an inorganic matrix based on natural lime is presented in this paper. The Sisal-NFRCM performances are investigated through tensile and single-lap shear tests, adopting the dispositions of the Round Robin Tests developed for the FRCM characterization by the RILEM Technical Committee 250-CSM. The tensile stress-strain curve evidenced the tension stiffening effect of the mortar between cracks, which tended progressively to reduce. In shear tests, the failure and the progressive slippage of the sisal yarns was observed. [ABSTRACT FROM AUTHOR]

Highlights • The behavior of concretes with polypropylene and sisal fibers was investigated. • Both fibers could provide similar residual strength, if at equivalent dosages. • Evaluation of fiber-matrix interface showed a similar behavior for both fibers. • The use of low alkaline matrix resulted in no degradation after ageing tests. Abstract This investigation aims to compare the mechanical behavior of concretes reinforced with polypropylene and sisal fibers. Both fibers were 51 mm long and were incorporated in fractions of 3, 6 and 10 kg/m3 into the matrices. The composites were tested under three-point monotonic and cyclic flexural loads. Pullout tests were performed to study the fiber-matrix interaction. It was observed that the sisal fiber could provide the same level of residual strength as the polypropylene fiber, as long as the equivalence of the dosages of the fibers is taken into account. The composites were classified according to fib Model Code 2010 based on parameters obtained from flexural tests. The durability of the composites was studied by assessing the flexural behavior after wetting and drying cycles. Concrete reinforced with both fibers did not present mechanical losses after the cycles. [ABSTRACT FROM AUTHOR]

The large-scale disposal of bottom ash resulting from municipal solid waste incineration poses a significant challenge in terms of effective management. While Lightweight aggregates made of municipal solid waste incinerated bottom ash, referred to as MSWI BA, show promise, their practical application is hindered by low structural strength and the presence of certain contaminants. To address this, a novel and green solution is proposed in this study, which involves utilizing sisal fibers (SF) to enhance the solidification of the synthesized aggregates. In this study, the synthesized lightweight aggregates (SLWAs) consisting of cement, different replacement levels of ground MSWI BA (60%, 70%, and 80%), and/or the cut SF were manufactured by a disc pelletizer. The influence of incorporating SF on the SLWAs was investigated across various aspects, encompassing the physical characteristics, strength performance, microscopic properties, and sustainability. The results showed that when SF was incorporated, the production efficiency of coarse SLWAs was considerably improved, especially up to a 66.5% increase with under the 70% replacement level of MSWI BA. Moreover, the surface roughness and strength were improved due to the SF addition. In the system of the CEM-MSWI BA matrix, the fiber incorporation not only accelerates the cement hydration reaction but also fills the pore generated from the swelling of metallic aluminum in MSWI BA, achieving the strength enhancement of SLWAs. More importantly, some contaminant ions including chloride, chromium, and copper from MSWI BA, could be effectively absorbed and solidified by the SF. Furthermore, the utilization of SF in SLWAs brings about great sustainability concerning greenhouse gas emissions and production costs. Consequently, incorporating SF proves to be an effective and green solution, thus promoting the practical implementation of the SLWAs. [Display omitted] • A novel and green approach is proposed to upgrade MSWI BA-based aggregates. • The cold-bonded pelletizing technique is employed to produce aggregates. • The filling effect of SF increases the strengths of the aggregates. • Sisal fiber addition effectively solidifies contaminant ions leaching. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effective modification of sisal fibers using XSBR emulsion was developed. • The polymeric layer in sisal fiber reduces water absorption by 80%, and also minimizes fiber alkaline degradation. • Effective polymeric coating transforms sisal structure, leading to substantial changes in the fiber's mechanical properties. • Polymer-coated sisal fibers presented enhanced adhesion and stability in cement-based matrices. The performance of sisal fibers in cement-based matrices is highly dependent on the interface efficiency between the fiber and the matrix. This behavior in turn is directly related to two main factors: the sisal fiber swelling tendency and fiber alkaline degradation. To enhance these properties and consequently the fiber–matrix adhesion, this study proposed the use of carboxylate styrene-butadiene rubber latex (XSBR) as a coating for sisal fibers. Different XSBR polymers and emulsions concentrations were adopted. The effects of this treatment on various properties of the fibers such as physical, chemical, and mechanical properties were studied. The physical properties of the modified fibers were investigated by means of scanning electron microscopy (SEM) and atomic force microscope (AFM) analyses. Also, changes in the moisture absorption capacity of the coated fibers were evaluated. To study the chemical influence of the polymer coating in the modified fibers, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques were adopted. Direct tensile and pullout tests were also assessed in natural and coated sisal fibers, to mechanically evaluate the modification in terms of fiber strength and adherence, respectively. The results evidenced the formation of a new polymeric layer around the fiber, responsible to reduce the water absorption tendency of the natural fiber. The increase in the fiber–matrix adhesion obtained in the pullout evaluation was attributed to the rougher superficial aspect of the modified fibers and increased chemical interaction between the polymer and the cementitious matrix. Moreover, it was proven that the polymeric layer reduced the fiber's alkaline degradation susceptibility resulting in a more stable sisal fiber. [ABSTRACT FROM AUTHOR]

[Display omitted] • Natural coarse aggregates were partially replaced by electronic plastic waste coarse aggregates (EPWCA). • Electronic waste concrete modified with nano iron oxide particles (NIOP) and sisal fiber (SsF) was investigated. • Mechanical and durability properties improved with the NIOP addition. • The addition of SsF greatly enhanced the concrete's resistance against tensile stresses. • Synergistic behavior of NIOP and SsF proved to be effective in improving the overall performance of EPWCA concrete. The utilization of electronic plastic waste (EPW) as a substitute for traditional aggregates in concrete has gained attention for its potential to reduce environmental waste. However, the incorporation of EPW aggregate leads to reduced mechanical properties, limiting its structural applications. This paper aims to address this issue by enhancing the mechanical and durability properties of EPW aggregate concrete by incorporating nano iron oxide particles (NIOP) and sisal fiber (SsF) reinforcement. Natural coarse aggregates were partially replaced with 30% EPW coarse aggregate (EPWCA). The performance of the resulting concrete was thoroughly investigated by incorporating 1% SsF and varying NIOP content from 1.0% to 4% of the cement's weight. The workability of concrete is compromised by the intrusion of both NIOP and SsF. However, the addition of SsF and NIOP decreases and increases the hardened density of the resulting concrete, respectively. The combined effect of NIOP and SsF reinforcement led to enhanced performance of EPW concrete, with the superior performance observed in the EPW concrete modified with 4% NIOP and 1% SF. This modification led to increases of approximately 15.81% in compressive strength, 22.80% in splitting-tensile strength, 21.75% in flexural strength, and 28.79% in bi-surface shear strength. In terms of durability, ultrasonic pulse velocity (UPV) values demonstrated a net increase of approximately 6.50%, while sorption and water absorption capacity showed reductions of approximately 8.04% and 4.52%, respectively. Moreover, the modified EPW concrete exhibited a net decrease of 28.79% in linear shrinkage compared to the control virgin concrete. Forensic investigations confirmed microstructural densification resulting from the addition of NIOP. Thus, the modified EPW concrete with NIOP and SsF reinforcement shows promise in enhancing overall performance and promoting eco-friendly construction practices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bacillus Subtilis based bio-healable concrete was analyzed against two successive damage cycles for the very first time. • Sisal fiber proved as a potential immobilizer for Bacillus Subtilis to develop robust self-healing concrete. • Average crack healing width of 0.48 mm and 0.28 mm was attained after the 1st and 2nd healing phases. • SEM, EDS, XRD, TGA, FTIR, and Raman spectroscopy affirmed bio-mediated calcite precipitation. Bio-healing is now believed as a promising technique for the repair of concrete cracks. However, the healing capability of bacterial mixes against repeated damage cycles is still questionable. This study aims to investigate the robustness of bio-healable concrete against two successive damage cycles using Bacillus Subtilis immobilized via sisal fiber. The formulated bio-concrete exhibited improved mechanical properties and attained a maximum of 13.96 % and 36.82 % enhancement in terms of compression strength and split tensile strength. Self-healing efficacy was assessed by quantifying the average crack healing width and the recovered strength in compression during the healing phase. Results revealed that sisal fiber efficiently preserves spores of the bacillus strain and enhances its bio-metabolic potential to precipitate calcite for sealing concrete cracks. The average crack of 0.48 mm width was successfully healed in the first damage cycle whereas the complete repair of a 0.28 mm wide crack on average was attained in the healing phase of the second damage cycle. The maximum recovered compressive strength was 82.65 % and 50.42 % in the two successive damage cycles through bio-healing. The crack-healing precipitate was identified as calcite crystals through forensic examination. Consequently, immobilizing Bacillus Subtilis with sisal fiber was proved as a viable approach for improving the mechanical properties of concrete and inducing robust self-healing in repeated damages. [ABSTRACT FROM AUTHOR]

• Alkali treatment improves the mechanical performance of sisal fibers. • Stretch of the fibers during treatment procedure results in enhanced fiber strength. • Treated sisal fibers present an improved bond with cement-based matrix. • Alkali-treated sisal fibers are more stable in alkaline aggressive conditions. This work aims to evaluate the effect of alkali treatment on sisal fibers to improve the fiber properties and the effectiveness of their use as reinforcement in cement-based matrices. Alkaline solution concentration (1, 5 and 10 wt% NaOH) and post-treatment protocol (use of distilled water or acetic acid) influence were evaluated. The physical, chemical, thermal, wettability and surface characteristics were analyzed. Also, single-fiber direct tensile and pullout tests were performed. Results showed an increase in cellulose proportion with a reduction in hemicellulose and lignin content upon alkali treatment. Consequently, enhanced thermal stability and a decrease on the water uptake tendency were reached. Additionally, improved tensile properties, as well as an enhanced bond with the cementitious matrix, were found for alkali-treated fibers. Also, fibers became more stable when subjected to alkaline aggressive conditions. Thus, the alkali-treated sisal fiber seems to be an adequate and sustainable alternative as reinforcement for cement-based matrices. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an experimental research on the durability performance of compression molded sisal fiber–cement mortar laminates (SFRML). To obtain a material with enhanced performance, the used methodology was to replace the Portland cement (PC) by calcined clay (metakaolin and calcined waste crushed clay brick) in order to produce a matrix totally free of calcium hydroxide (CH). The content of calcium hydroxide in the matrix was determined by thermal analysis. SFRML were then produced using both a PC and a CH-free PC-calcined clay matrix and the composites were submitted to accelerated aging through cycles of wetting and drying. The durability of the SFRML was investigated by determining the effects of accelerated aging on the microstructures and flexural behavior of the composites. The results indicate that the newly developed CH-free matrix avoided the fiber embrittlement process keeping the toughness in time even after 100 cycles of wetting and drying. [Copyright &y& Elsevier]

Abstract: The objective of this work was to analyze mechanical, physical and thermal performance of roofing tiles produced with several formulations of cement-based matrices reinforced with sisal and eucalyptus fibers. The physical properties of the tiles were more influenced by the fiber content of the composite than by the type of reinforcement. The type of the fiber was the main variable for the achievement of the best results of mechanical properties. Exposure to tropical climate has caused a severe reduction in the mechanical properties of the composites. After approximately four months of age under external weathering the toughness of the vegetable fiber–cement fell to 53–68% of the initial toughness at 28 days of age. The thermal performance showed that roofing tiles reinforced with vegetable fiber are acceptable as substitutes of asbestos–cement sheets. [Copyright &y& Elsevier]

• Humidity variations barely altered the mechanical properties of jute fiber. • Sisal fiber presented better adhesion under the proposed humidity levels. • Humidity effect on fibers can be assessed by their cellulose crystallinity index. • Sisal fiber presented better adhesion under the proposed humidity levels. The aim of this study is to determine how the mechanical behavior of natural fibers is affected by the environmental and internal relative humidity, especially on the fiber-matrix interface. For that, curauá, jute and sisal fibers were selected. The experimental program commenced determining the fibers' mechanical properties under tensile stresses, followed by X-ray diffraction measurement, thermogravimetric analysis, infra-red spectroscopy and dynamic water vapor sorption analysis, as well as a microscopic examination of fibers' rupture under tensile stresses. In addition, a 2D finite element analysis was carried out to assist the interpretation of the mechanical behavior of the pull-out tests. The results indicate that the absorption capacity of each fiber can be correlated to the amount of hemicellulose and cellulose cristalinity, and the fibers' swelling process was influenced by each microstructure and hemicellulose content. Results from the mechanical tests showed a strength enhancement when the fibers were submitted to low levels of relative humidity, while a drastic decrease in strength was observed along with higher levels. The development of finite element models helped understanding the geometric particularities of each fibers. From the results it is possible to state a unique correlation between each fiber and its respective moisture content. It is believed that this data can help the use of such fibers as reinforcement of cement-based systems and their durability under a wider range of relative humidity levels. [ABSTRACT FROM AUTHOR]

• A low energy-consumption and sustainable sisal fibers reinforced UHPC was manufactured. • The flexural strength and toughness of UHPC were significantly improved by adding sisal fiber. • The bond behavior between sisal fiber and UHPC was studied. • The distribution of sisal fiber in the matrix was observed by fluorescent whitening agent solution and ultraviolet light. This paper investigated the utilization of natural sisal fibers in ultra-high performance concrete (UHPC). UHPC mixtures containing sisal fibers with different lengths (6, 12, and 18 mm) and volume contents (1.0%, 2.0%, and 3.0%) were prepared. Flowability, mechanical strength, and interfacial bond behavior between fiber and matrix were tested for every mixture. The distribution of sisal fibers in the UHPC matrix was evaluated using the ultraviolet (UV) light and fluorescent whitening agent (FWA). Finally, the microstructures of typical samples were observed by a scanning electron microscope (SEM). Experimental results indicated that the flowability of the fresh UHPC mixture decreased with the increase of length and volume fraction of sisal fibers. The content of 2.0% sisal fibers with a length of 18 mm increased flexural strength and toughness of UHPC by 16.7% and 540.0%, respectively, compared with plain UHPC specimens. The pull-out load and pull-out energy increased with the length of sisal fibers. Moreover, the sisal fibers can be uniformly distributed in the UHPC matrix. Therefore, the utilization of sisal fibers to manufacture a low-cost and low energy-consumption UHPC has great potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • The addition of fiber can promote the adsorption of PCE. • Increased fiber length, dosage, roughness and hydrophilicity led to worse fluidity of the cement paste. • Plant fiber has a significant influence on the performance of cement paste. Compared with most common construction materials, fiber reinforced cementitious materials are well known to exhibit better physical, working and mechanical properties. In this study, three fibers were selected: polypropylene fiber (PPF) and polyvinyl alcohol fiber (PVAF), which represented synthetic fibers, and sisal fiber (SF), which represented natural fibers. Effects of these fibers on the flowability, rheological properties, and adsorption behavior of the cement paste with polycarboxylate superplasticizer (PCE) were investigated. Furthermore, the above experimental results were verified by measuring the contact angle of the fiber with water and PCE solution and the apparent morphology of the fiber. Results revealed that the addition of fibers significantly reduces the fluidity of the cement paste, while the yield stress and plastic viscosity of the cement paste increase with the addition of fibers. From the contact angle and scanning electron microscope, the surface of SF was relatively rough, and the contact angle of SF with water or PCE solution was the smallest. It can be concluded that the plant fiber has a significant influence on the fluidity and rheology of cement paste. [ABSTRACT FROM AUTHOR]

• Developed TBCP/bioepoxy blends and TBCP/sisal/bioepoxy composites. • The incorporation of TBCP enhanced the mechanical properties of the bioepoxy. • Addition of TBCP improved the interfacial interaction between the sisal and bioepoxy. • Both bioepoxy blends and composites can be used for semi-structural applications. As one of the goals in recent research and development is to use eco-friendly materials from sustainable resources to manufacture a product material. Bioepoxy resin is a relevant choice to maximize the natural content of the composites along with natural fiber as a reinforcement material. This work presents the effect of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) triblock copolymer in bioepoxy and bioepoxy composites prepared by sisal fibers. Incorporation of the triblock copolymer in bioepoxy resin enhances the tensile, flexural, and impact properties. The viscoelastic properties show good plasticization of the triblock copolymer with the bioepoxy matrix. The contact angle increases in the presence of the triblock copolymer, while the water absorption is marginally decreased. To the best of our knowledge, the modification of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) triblock copolymer with bioepoxy resin has not been reported to date. Further poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) triblock copolymer was used as a modifier for sisal fiber fabrics-reinforced polymer composites. The tensile, flexural, and impact properties improve to some extent. [ABSTRACT FROM AUTHOR]

• Sisal and coconut fibers were incorporated in the geopolymer mortar. • The properties of geopolymer mortar reinforced with fibers were tested. • The natural fibers test results were compared with synthetic fiber (glass fiber). • Natural fiber significant improves the indirect tensile strength similar to glass fiber. This study investigated the properties of high calcium fly ash geopolymer mortars containing natural fibers. Two types of natural fibers, namely sisal fiber and coconut fiber were incorporated in the geopolymer mortar with varying proportions at 0%, 0.5%, 0.75%, and 1.0% volume fraction. The mechanical, thermal, and physical properties of geopolymer mortar reinforced with fibers were tested and compared with those of glass fiber (synthetic fiber) and control (0% fiber) geopolymer mortars. Results revealed that the addition of natural fiber (sisal and coconut fibers) as reinforcing materials resulted in significant improvement in tensile and flexural strength performances similar to the use of glass fiber. Meanwhile, the workability, dry density, ultrasonic pulse velocity, and compressive strength values tended to decrease. [ABSTRACT FROM AUTHOR]