•Summarizing the latest research on vegetable fiber cement-based composites.•Reviewing the fibers used, procedures, mechanical performance and durability.•Durable cement composites with optimized ...fiber–matrix adhesion have been developed.•Best performance with vegetable fiber textile reinforcements.
In the last few years, an increase in interest has been given to the use of cellulose fibers as alternatives for conventional reinforcements in composites. The development of commercially viable environmentally friendly and healthy materials based on natural resources is on the rise. In this sense, cellulosic fibers as reinforcements for cement mortar composites constitute a very interesting option for the construction industry.
This paper presents a review of the research done during the last years in the area of the cement-based composites reinforced with cellulose fibers. The fibers used, processing methods, mechanical behavior and durability are presented. The main achievements found have been the development of durable cement composites with optimized fiber–matrix adhesion. Moreover, the recently developed textile composites will allow obtaining high performance materials reinforced with vegetable fibers.
Currently, millions of tons of textile waste from the garment and textile industries are generated worldwide each year. As a promising option in terms of sustainability, textile waste fibers could be ...used as internal reinforcement of cement-based composites by enhancing ductility and decreasing crack propagation. To this end, two extensive experimental programs were carried out, involving the use of either fractions of short random fibers at 6-10% by weight or nonwoven fabrics in 3-7 laminate layers in the textile waste-reinforcement of cement, and the mechanical and durability properties of the resulting composites were characterized. Flexural resistance in pre- and post-crack, toughness, and stiffness of the resulting composites were assessed in addition to unrestrained drying shrinkage testing. The results obtained from those programs were analyzed and compared to identify the optimal composite and potential applications. Based on the results of experimental analysis, the feasibility of using this textile waste composite as a potential construction material in nonstructural concrete structures such as facade cladding, raised floors, and pavements was confirmed. The optimal composite was proven to be the one reinforced with six layers of nonwoven fabric, with a flexural strength of 15.5 MPa and a toughness of 9.7 kJ/m
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•Short textile waste fibers (TWF) as reinforcement of cementitious materials are investigated.•Design-oriented mechanical and durability properties were characterized by testing.•8% of TWF proved to ...be the optimum dosage for building components with limited structural responsibility.•Accelerated aging on TWF composites led to lower detrimental effects in comparison with those on control samples.
Fiber reinforced mortars (FRM) are growingly used in several fields of building technology (e.g., façade panels, roofing, raised floors and masonry structures) as building elements. One of the promising type of fiber for these composite materials can be textile waste originated from cloth wastes. The use of this sort of recycled materials and wastes as cement reinforcement within the building sector can play a relevant role in sustainability, both the environmental, economic and social perspectives. In this paper, the design mechanical properties (flexural and compressive strengths at 7, 28 and 56 days as well as toughness and stiffness) together with durability properties of cement pastes reinforced with short Textile Waste Fiber (TWF) in contents ranging from 6 to 10 % by weight fraction cement was investigated. The results were compared with those obtained from Kraft Pulp pine Fiber (KPF), taken as reference. The main conclusion is the feasibility of using this type of fiber as potential reinforcement in construction materials with the optimum dosage of 8%. Although the flexural resistance and toughness of the TWF composite are lower than KPF control by almost 9%, the compressive strength and stiffness together with durability properties have proven to be enhanced respect to the reference composite.
The aim of this study is to develop a process to produce high-performance cement-based composites reinforced with flax nonwoven fabrics, analyzing the influence of the fabric structure-thickness and ...entanglement-on mechanical behavior under flexural and tensile loadings. For this purpose, composite with flax nonwoven fabrics with different thicknesses were first prepared and their cement infiltration was evaluated with backscattered electron (BSE) images. The nonwoven fabrics with the optimized thickness were then subjected to a water treatment to improve their stability to humid environments and the fiber-matrix adhesion. For a fixed thickness, the effect of the nonwoven entanglement on the mechanical behavior was evaluated under flexural and direct tension tests. The obtained results indicate that the flax nonwoven fabric reinforcement leads to cement composites with substantial enhancement of ductility.
Utilizing recycled fibers as reinforcement in cement-based matrices is an effective means of promoting waste recycling and adopting a circular economy approach in the construction industry. Within ...this framework, the recycling and potential reutilization of textile residues can improve the pre- and post-cracking performance of cement-based matrices intended for building components with up to intermediate structural responsibilities (i.e., panels and cladding elements for buildings). This research is focused on the mechanical and durability -through forced aging of dry-wet and freeze-thaw cycles- experimental characterization of laminated fabric-reinforced cementitious matrices (FRCMs) containing 4 and 6 nonwoven fabric layers obtained from end-of-life fire-protecting t-shirts. For this purpose, both direct and flexural tensile tests were conducted to characterize the mechanical performance of the composite. The tests on the 6-fabric layers produced panels with Portland Cement (PC) matrix, after 28-day of curing, led to average values of the maximum tensile strength of 3.7 MPa with associated toughness index superior to 25 kJ/m2, and mean modulus of rupture of 11.6 MPa with a fracture energy index of 4.3 kJ/m2. After dry-wet accelerated aging, the post-cracking performance of the developed composites decreased (on average, 40% in toughness and 11% in strength) due to fiber embrittlement. To better understand the performance of aged composites, shredded fibers recovered from protective clothing (mainly consisting of meta-aramid fibers) were immersed in the binary matrix. Accordingly, the mechanical properties of the fibers after 5 and 10 cycles of dry-wet aging were studied. Based on the results, replacing partially PC by silica fume (between 30% and 50%) was seen as a sustainable alternative to improve the performance of the aged fibers by more than 10%.
•Textile waste recycled fibers as nonwoven fabrics for reinforcing cementitious matrices.•Uniaxial and flexural tensile properties of unaged and aged nonwoven FRCM were characterized.•Comparative analysis with other matrices reinforced with synthetic and vegetal fabrics.•Evaluation of Silica Fume content (0–50%) impact on tensile properties of aged recycled fibers.
•Mechanical performance and durability of OPC/flax nonwovens composites for façade pieces is explored.•The effect of two pozzolanic additions combined with nonwoven treatment is ...evaluated.•Significant improvements in the durability using treated nonwovens.
This experimental research analyzes the mechanical performance and durability of façade pieces based on Portland cement matrix and flax nonwovens as reinforcement. Two types of pozzolanic additions (silica fume and metakaolin) combined with nonwovens subjected to different treatments to decrease their water absorption are analyzed as potential materials for fiber-cement sheets for building envelopes with high strength and durability. For this purpose, on the one hand, the mechanical performance and chemical composition of various ternary compositions were studied. On the other hand, various treatments were performed on the nonwovens and the nonwoven–matrix adherence was also analyzed. Finally, composites were prepared from some selected treated nonwovens and matrix mixtures, and their mechanical properties and durability were evaluated under four-point bending tests after 28days of curing in a humidity chamber and after accelerated aging. The composites developed with the treated nonwovens presented very high performance combined with enough durability to be potential candidates for the development of sustainable materials for building envelopes.
This paper analyses the influence of the addition of low content (0.1 to 0.8 wt%) of nanofibrillated cellulose (NFC) or cellulose nanocrystals (CNC) on the flexural performance, durability and ...microstructure of calcium aluminate cement (CAC) cured at 20 °C or 60 °C. The relationship between the mechanical properties and the microstructure of the cement was evaluated after curing and further after accelerated aging by flexural testing and X-ray diffraction and by backscattered electron imaging, respectively. The addition of 0.1–0.2 wt% of either nanocellulose led to an increase in the modulus of rupture (MOR) and modulus of elasticity (MOE) values. Moreover, CNC was effective to counteract the negative effects of increased porosity of CAC cements before and after aging, significantly improving their mechanical performance and durability. This effect was not observed in Portland cement systems, in which the addition of this low nanocellulose content did not lead to significant changes.
A combination of reinforcements at different levels can have a synergetic effect on the final properties of a composite. The aim of this work was to produce, evaluate, and compare the wet/dry cycling ...durability of the exposure of cement composites reinforced with conventional pulps at the micro-scale level, with nanofibrillated cellulose fibers at the nano-scale level, and with combinations of both reinforcements (hybrid composites). To evaluate the durability of their mechanical properties, the composites were tested under flexural loading after 28 days of humidity chamber curing and after 20 wet/dry accelerating aging cycles. Composites reinforced with the nanofibrillated cellulose exhibited significantly higher flexural strength and flexural modulus, but they had lower fracture energy values than those reinforced with conventional sisal fibers. Moreover, the hybrid composites with a high content of nanofibrillated cellulose maintained or even improved their properties after aging.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This research analyzes the effects of different treatments on flax nonwoven (NW) fabrics which are intended for composite reinforcement. The treatments applied were of two different kinds: a wet/dry ...cycling which helps to stabilize the cellulosic fibers against humidity changes and plasma treatments with air, argon and ethylene gases considering different conditions and combinations, which produce variation on the chemical surface composition of the NWs. The resulting changes in the chemical surface composition, wetting properties, thermal stability and mechanical properties were determined. Variations in surface morphology could be observed by scanning electron microscopy (SEM). The results of the X-ray photoelectron spectroscopy (XPS) showed significant changes to the surface chemistry for the samples treated with argon or air (with more content on polar groups on the surface) and ethylene plasma (with less content of polar groups). Although only slight differences were found in moisture regain and water retention values (WRV), significant changes were found on the contact angle values, thus revealing hydrophilicity for the air-treated and argon-treated samples and hydrophobicity for the ethylene-treated ones. Moreover, for some of the treatments the mechanical testing revealed an increase of the NW breaking force.
In this work, nanofibrillated cellulose (NFC) has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties ...(cellulose content and microfibrillar angle), sisal, and cotton linters pulps, were initially characterised in order to assess their reinforcing capability. Sisal pulp was found to be most suitable as reinforcement for the brittle cementitious matrix. Nanofibrillated cellulose was produced by the application of a high intensity refining process of the sisal pulp. It was found that 6 hours of refining time was required to obtain the desired nanofibrillation of the fibers. Cement mortar composites reinforced with both the sisal fibres and the nanofibrillated cellulose were prepared, and the mechanical properties were determined under flexural tests. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited enhanced flexural properties, but lower values of fracture energy, than the ones reinforced with the conventional sisal fibres.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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