Rubber Fiber Research Articles

Evaluation of the effects of textile fibre derived from end-of-life tyres (TFELT) on the rheological behaviour of asphalt binders

End-of-Life Tyres (ELT) consist of rubber, steel and textile fibre (TFELT). Unlike rubber and steel, the possibilities for the re-use of TFELT are limited, and its final disposal is an environmental problem. This article explores an alternative re-use of TFELT as an additive for asphalt binder (AB). The TFELT was characterised using scanning electron microscope (SEM), polarized microscopy and thermogravimetric analysis. Two Asphalt Binders (AB14 and AB24) and three addition percentages (0.1%, 0.3% and 0.5%) were evaluated. The effects on the physical properties at high, intermediate and low temperature were studied by determining the softening point, penetration and FRAASS breaking point. We also evaluated the effects on the rheological properties, by determining the rutting and fatigue parameters at different states of ageing (short and long term). Resistance to the accumulation of deformations was measured by applying the Multiple Stress Creep Recovery test (MSCR), and resistance to fatigue by the Linear Amplitude Sweep test (LAS). The results showed significant effects in reducing the accumulation of permanent deformation, by up to 40% for the addition of 0.5% TFELT, without any reduction in properties of resistance to thermal cracking.

Behavior of ternary blended cementitious rubberized mixes reinforced with recycled tires steel fibers under different types of impact loads

This research primarily investigates the influence of incorporating steel fibers (recycled and manufactured) in Rubberized concrete (RuC) mixes on impact resistance. Impact resistance was comprehensively investigated for six steel fiber reinforced RuC (SFRRuC) mixes with a large volume of rubber, reaching a replacement of 40 % of fine and coarse aggregates. Besides mechanical properties, four different types of impact tests, including drop weight on concrete discs and prisms, rebound, and projectile impact, were performed. The impact results indicate that the incorporation of blended fibers in the RuC mixes substantially enhances the initial and failure impact energy of SFRRuC under drop weight tests on discs and prisms. The excellent impact performance was further confirmed by the results of the projectile impact test on concrete slabs, where the ejected mass as well as the crater sizes for the concrete slab containing 40 % rubber and steel fiber were the lowest, as the dual effect of rubber and steel fibers enhanced the ductility, toughness, and penetration resistance. Overall, the improved impact, flexural resistance and toughness index of SFRRuC compared to the plain concrete mix makes it a potential alternative and sustainable construction material for various applications including industrial floors and protective wall barriers in military structures.

Influence of Basalt Fiber on Mechanical Properties and Microstructure of Rubber Concrete

The utilization of waste rubber in concrete will reduce pollution and improve the efficiency of resource utilization. The effects of rubber particles and basalt fibers on the compressive strength and splitting tensile strength of concrete were investigated. In addition, the influence of basalt fibers on the mechanical properties and micropore structure of rubber concrete (RC) were analyzed using scanning electron microscopy (SEM) and X-ray computed tomography (CT). The distribution of rubber particles in concrete was also studied. The results indicate that the effects of basalts fibers on the mechanical properties of rubber concrete were significant. The rubber particles were evenly distributed in the concrete. Compared with normal concrete (NC), rubber concrete with 10% rubber particles had lower compressive strength and splitting tensile strength. Compared with rubber concrete, basalt fiber rubber concrete (BFRC) with 2% basalt fibers had no obvious effect on the compressive strength, while significantly improving the splitting tensile strength, refining the pores of rubber concrete, and reducing the porosity of the matrix. The effects of basalt fiber on the properties and pore distribution of RC should be considered in future applications.

Experimental investigation on static compressive toughness of steel fiber rubber concrete

Abstract Recycled rubber particles can be produced by using waste tires. Adding recycled rubber particles to concrete can form rubber concrete (RC). RC can not only reduce the amount of natural sand and reduce the cost of concrete but also improve the static compressive toughness of concrete. Adding steel fiber into RC can improve the strength of concrete. In order to study the compressive toughness of steel fiber rubber concrete (SFRC), rubber particles washed with NaOH are added to steel fiber reinforced concrete. This can enhance the bonding performance between the recycled rubber particles and concrete. The volume ratio of recycled rubber is 5, 10, and 15%. Prismatic and cubic test blocks were prepared and their compressive tests were carried out. The results show that the stress interaction between the rubber particles and steel fiber in concrete significantly improves the compressive strength, elastic modulus, and stress–strain relationship of concrete. The compressive toughness and ductility of concrete are improved. When the content of rubber particles is 15–20%, the compressive toughness of SFRC is improved most obviously. Through experiments, the toughness index and specific toughness of rubber steel fiber reinforced concrete are calculated, which explores a new way and method for studying the compressive toughness of similar recycled material concrete.

Low-Cost Self-Calibration Data Glove Based on Space-Division Multiplexed Flexible Optical Fiber Sensor.

Wearable devices such as data gloves have experienced tremendous growth over the past two decades. It is vital to develop flexible sensors with fast response, high sensitivity and high stability for intelligent data gloves. Therefore, a tractable low-cost flexible data glove with self-calibration function based on a space-division multiplexed flexible optical fiber sensor is proposed. A simple, stable and economical method was used to fabricate flexible silicone rubber fiber for a stretchable double-layered coaxial cylinder. The test results show that the fiber is not sensitive to the temperature range of (20~50 °C) and exhibits excellent flexibility and high stability under tensile, bending and torsional deformation. In addition, the signal detection part of the data glove enables compact and efficient real-time information acquisition and processing. Combined with a self-calibration function that can improve the accuracy of data acquisition, the data glove can be self-adaptive according to different hand sizes and bending habits. In a gesture capture test, it can accurately recognize and capture each gesture, and guide the manipulator to make the same action. The low-cost, fast-responding and structurally robust data glove has potential applications in areas such as sign language recognition, telemedicine and human–robot interaction.

Mix design, mechanical properties and durability of the rubberized geopolymer concrete: A review

Rubberized geopolymer concrete (RGPC) is an innovative, user and environmentally friendly invention in building materials that require less energy to manufacture and have a lower carbon footprint than cement-based systems, alleviating global warming concerns. It has the potential of reducing the dilemma of disposal of the huge rubber tire wastes by including them in production as a partial substitute for natural fine aggregate. This hereby avoids the depletion of natural mineral aggregates and protects against air, water and soil pollution. The current review shows the feasibility of incorporating waste rubber fibers in geopolymer concrete (GPC), which emits 90% less carbon dioxide when compared with ordinary Portland cement (OPC), to address the issues mentioned above. To the author's knowledge, no comprehensive studies have reviewed the properties, durability, mechanical, mix design and carbon footprint, of RGPC. For strength characterization, this review work analyzed the flexural, split tensile, and compressive strengths of RGPC. To review the durability characterization of RGPC, water absorption, acid resistance, chloride diffusion, sulfate resistance, and water permeability were evaluated. Finally, the outcome of this review concludes that RGPC has distinct, tangible benefits compared with OPC concrete regarding environment protection, durability, and strength properties. Furthermore, RGPC is recommended for producing lightweight concrete and civil engineering structures when compressive strength is not the main property.

Microstructure-properties of dynamically vulcanized mengkuang leaf fibre/ethylene vinyl acetate/natural rubber thermoplastic elastomer composites

Thermoplastic elastomer composites based on ethylene vinyl acetate (EVA), natural rubber (NR), and Mengkuang leaf fibre were prepared using the sulfur and peroxide vulcanization systems. Different curing systems and fibre loadings affecting the processing torque, tensile, thermal, and morphology of the composites were investigated. Addition of Mengkuang leaf fibre resulted in poor fibre dispersion and agglomeration in the matrix, which may have affected the efficiency of stress transfer and thus could explain a decline in tensile and thermal properties. Composites with dynamic vulcanization showed a rougher surface that might be due to the presence of crosslinking, which requires more force to fail. The increase in stabilization torque for the composites with dynamic vulcanization was observed due to the addition of curing agents, which implies some changes at the molecular level due to crosslinking. Tensile properties of Mengkuang leaf fibre filled EVA/NR composites indicated that the tensile strength, elongation at break, and Young’s modulus of the peroxide cure system were higher than the sulfur cure system and unvulcanised composites. The sulphur cure system showed better resistance towards thermal degradation compared to the peroxide cure system. This was attributed to dicumyl peroxide (DCP), which degrades the polymer chain or the composites at high temperature.

Effect of binder dosage and the use of waste rubber fiber on the mechanical and durability performance of geopolymer concrete

This paper was designed to find solutions to the fact that the availability of natural aggregates in accordance with the standards used in concrete is gradually decreasing, the environmental problems caused by cement threaten our future, and the recycling of used tire waste is very difficult. The effects of three different binder dosages (300, 400 and 500 kg/m3) on the mechanical and durability properties of geopolymer concrete (GPC) samples were investigated in binder contents consisting of 98% granulated blast furnace slag (GBFS) and 2% nano silica. As for the aggregate composition, natural sand was used as the fine aggregate, while the waste rubber fibers (WRF) were substituted in different proportions (0%, 5%, 10% and 15%) of the coarse aggregate by volume. Following the solid part was obtained as described, the alkaline activation of GPC specimens was provided using a 12 M NaOH solution. At the end of 28-day curing period, compressive strength, flexural strength, splitting tensile strength, impact resistance, capillary permeability and elevated temperature performance properties were investigated in detail and the results obtained from the mentioned tests were also confirmed by microstructural analysis. Experimental findings revealed that the increase in binder dosage resulted in significant increases in all of the mechanical properties, and it was speculated that this was due to the formation of a denser and more compact microstructure compared to their counterparts produced using lower binder dosage. Besides the negative effects of WRF usage on compressive strength and resistance of elevated temperature, the other performance criteria such as flexural strength, impact resistance and splitting tensile strength values of GPC samples significantly improved with the usage of WRF. As a result, experimental findings demonstrated that the usage of waste rubber fibers in the production of GPC was advantageous in terms of some mechanical and durability properties.

Investigating the effect of powder recoater blade material on the mechanical properties of parts manufactured using a powder-bed fusion process

As additive manufacturing (AM) technology grows, more industries are learning how to utilize it for their specific applications. Powder bed fusion-based AM processes such as Direct metal laser solidification (DMLS) allow manufacturers to design more intricate or lightweight parts that could not be made with traditional tools. DMLS expands the capabilities of manufacturing, but the recoater blade that spreads powder presents challenges in printing delicate details such as lattice structures and high aspect ratio features. Hard steel or ceramic blades are often used to compact powder to create smooth, even layers that result in higher strength values of parts. However, small structures can be damaged by these blade types. Alternatively, a softer rubber or carbon fiber brush can be used to make the printing process easier by not breaking the small, printed features. On the other hand, parts made with softer blades are expected to have less strength and more defects. To compare the mechanical properties of finished parts due to blade type, 3 blade materials, high-speed steel (HSS), silicone rubber, and carbon fiber brush, were compared in this study. Tensile bars, cubes, and Voronoi lattice structure pucks were printed and analyzed for tensile properties, optical density analysis, as well as compression strength or toughness. These tests are often completed by original equipment manufacturers (OEM’s) in the AM industry to qualify the machine’s process. There were no significant tensile strength differences noticed of parts based on blade type and the values were all within the tolerance of OEM specifications. Optical density analysis indicated that the rubber blade builds have a higher number of large defects, greater than 75 μ m, and the brush blade has a higher number of small defects, less than 75 μ m in size. The HSS blade has zero defects greater than 90 μ m. There was no significant difference in maximum compression strength for the three blades, but the HSS blade produces parts with a standard deviation of toughness that is half of the other two blades. Inconsistencies shown in the soft blade builds may be due to the nature of the soft blades wearing faster over time during each build, however, the soft recoater blades can be a useful option if the application allows for occasional inconsistency.

Comprehensive Study for Engineering usage of Sustainable Concrete using Recycled Coarse Aggregates, Crumb Rubber and Steel Fibers

As per records of Transparency Market Research, yearly construction waste is expected to reach 2.20 billion tons by the year 2025. With such a large volume of construction and demolition trash, the 3R’s (Reduce, Reuse and Recycle) play a vital role in waste management. According to the EPA (Environmental Protection Agency), C&D garbage rose by 220 percent in metropolitan cities from 1990 to 2018. The present study focuses on usage of substitution by recycled coarse aggregate with natural coarse aggregates on the outskirts of major metropolitan centers, as well as crumb rubber, a waste created by tire waste disposal, to make the concrete more inexpensive and eco-friendlier. The study also supports the usage of crumb rubber waste that can be safely used for hydraulic structures with less load, such as weir structures or smaller check dams, while a 50 percent replacement of recycled coarse aggregate with natural coarse aggregate had the same strength as normal concrete, which is useful in sustainable concrete practices and can help reduce the generation of C & D waste. In this study, the concrete made up of using recycled aggregate is also mixed with steel fibers to enhance its workability.

Performance Characterisation of a New Plaster Composite Lightened with End-of-Life Tyres' Recycled Materials for False Ceiling Plates.

Plaster is one of the most used and studied materials in the building process. This paper shows the result of the characterisation of a new plaster-based material enlightened and reinforced with polymers and end-of-life tyres’ recycled materials. As far as end-of-life tyres are a common waste item, this paper offers new recycling possibilities, as well as significant improvements in new building materials. Mechanical, thermal conductivity, sound absorption, fire reaction and environmental impact are studied and analysed. Three different end-of-life tyres’ recycled materials are used, two size rubber and textile fibres. A significant density reduction up to 17% was achieved mainly due to end-of-life materials lower density. Two thermal conductivity measurement methods, heat flux meter and guarded hot plate, were conducted and then compared. A 20% improvement with respect to the reference was achieved in those samples with textile fibre. The two methods’ measurements got a 1% difference in all samples analysed except textile fibre. Thus, this allowed to validate these methods and assure these measurements. Sound absorption was also measured. These materials reached α = 0.32 in high frequencies. Performance in low frequencies were lower. Fire tests led to no ignition results and no fire propagation. Finally, a basic global warming potential impact study based on environmental product declaration (EPD) is conducted. The most relevant result of this study is the potential 20–34% reduction of CO2 emissions with the elaboration of these composites.

Development of a New Additive Based on Textile Fibers of End-of-Life Tires (ELT) for Sustainable Asphalt Mixtures with Improved Mechanical Properties.

End-of-life tires (ELT) are a worldwide problem. Rubber, steel, and different textile fibers are the by-products of ELT. Unlike rubber and steel, waste tire textile fibers (WTTF) are disposed of in landfills or burned. This study developed an additive made with WTTF to be incorporated into conventional hot mix asphalt (HMA), and its performance properties were evaluated. First, a characterization of the WTTF used was made and a manufacture protocol was established. Then, a reference HMA was designed and mixtures with different addition percentages (2%, 5% and 8%) of the WTTF-based additive were evaluated. The mechanical properties studied were stiffness modulus, moisture susceptibility, rutting resistance, stripping, and cracking resistance. The results indicated that the addition of the 2% and 5% WTTF-based additive improved these performance properties. Moreover, all addition percentages of the WTTF-based additive evaluated demonstrated a decrease of over 29% in permanent deformation according to the Hamburg Wheel Tracking Test. Thus, the use of the WTTF would not only be valuing a waste, but an asphalt mixture with improved properties would be obtained, contributing to the circular economy by reusing a material and prolonging the useful life of the asphalt mixture.

CARACTERIZAÇÃO DE COMPÓSITO CIMENTÍCIO REFORÇADO COM FIBRAS DE BORRACHA DE PNEU

The incorporation of fibers in cementitious composites has been widely researched, with the purpose of seeking new technologies, aiming to improve the properties of this material. The present work aims to study the addition of synthetic fibers, specifically, tire rubber fibers in cementitious composites, approaching the preparation, molding and analysis of the technical results of the samples with addition of fibers in relation to the reference samples, without the addition of fibers. Experimental tests were carried out on two concrete mixes, concrete with the addition of rubber (called in the present work as reference concrete) and concrete with 10% of the addition of rubber, where the specimens of the following dosages were submitted to axial compression tests. The results obtained show that the addition of rubber causes a reduction in the mechanical strength of the concrete, which can reduce the applications of this new material, although it has given it greater ductility, in addition to this advantage, the insertion of tire rubber in the concrete contributes to recycling of a polluting material and that is usually disposed of in the environment in an erroneous way

Laboratory Device Detecting Tensile Forces in the Rope and Coefficient of Friction in the Rope Sheave Groove

One of the possible ways to transfer the tractive power of a drive unit to the traction element is to use fibre friction. When a steel rope is used as the traction element, there is a transfer of tractive power in the groove created on the perimeter of the rim of the driving rope sheave. The transmission capability of the drive is directly proportional to the size of the angle of wrap and the shear friction coefficient of the rope surface when the rope is in contact with the surface of the groove wall. The relationship for calculating the size of friction coefficient in the grooves is given by relevant technical standards. The coefficient of friction determined in this way does not take into account the state of possible operational contamination of the groove or the diameter of the rope used. Using a unique laboratory instrument, tensile forces were measured for both rope sides in the state of a non-rotating sheave or when the sheave started to rotate rope. Experimental measurements were carried out for two different diameters of steel ropes, which were guided by two types of grooves for the rope sheave under two limit operating states of the groove wall surface: clean and dirty with oil. By evaluating the measured tensile forces in the approaching and outrunning rope side girded with the groove of the rope sheave, it was found (using a measuring apparatus) that a rope of a larger diameter acquires a higher value of the friction coefficient for the groove than a rope of a smaller diameter. The coefficient of friction in the groove decreases with the increasing size of the sum of the acting tensile forces on both sides of the rope. Lower values of the coefficient of friction achieve semi-circular grooves, and V-shaped grooves show higher values. Lower values for the coefficient of friction, close to theoretical values which were calculated using the relevant relationships specified in the standards, were found for grooves contaminated with oil as opposed to dry and clean grooves.

Influence of Crumb Rubber and Coconut Coir on Strength and Durability Characteristics of Interlocking Paving Blocks

Interlocking Paving Blocks (IPB) are, nowadays, a widely used construction material. As a result of the surge in demand for IPBs, alternative materials have been investigated to be used for IPBs. This study investigated the strength and durability characteristics (compressive strength, split tensile strength, density, water absorption, skid resistance, and abrasion resistance) of IPBs in the presence of (waste materials) crumb rubber (CR) and coconut coir fibers (CCF). Both compressive and split tensile strength increased in the presence of CCF to a certain extent. CR-based IPBs showcased an increase in skid resistance that satisfied both SLS 1425 and BS EN 1338 specifications. Abrasion depths of CR-based and CCF-based samples show a comparable increase in values when the respective fraction (CR or CCF) increases. Therefore, this research fills the knowledge gap, highlighting the importance of incorporating waste materials (CR and CCF) for the IPB industry rather than open dumping.

Progressive collapse behavior of steel fiber-reinforced rubberized concrete frames

The efficiency of combining fine aggregate's (sand) partial replacements with waste crumb rubber (CR) and steel fiber (SF) has been investigated in this paper. The study aims to enhance the RC frame's deformability, as well as its structural ductility to achieve progressive collapse resistance. To this end, a total of four RC frames' behavior at one-third scale under a situation of a middle-column removal was experimentally tested. Two frames were made of 0% CR and SF. Another two frames were made by incorporating CR at 20% by volume for the sand replacement and 0.5% SF fraction volume. The findings of the study reported an enhanced structural ductility, which was stimulated by incorporating CR and SF in normal concrete. The tested steel fiber-reinforced rubberized concrete frames, however, showed further deflection by 29.5% compared with the conventional frames.

The Properties of Micro Carbon Fiber Composite Modified High-Viscosity Asphalts and Mixtures.

In order to produce a high-viscosity asphalt and mixtures that can be used for ultra-thin overlays, high contents of Styrene–butadiene–styrene (SBS, 5%, 6%, 7%), styrene butadiene rubber (SBR, 1%, 2%, 3%) and micro carbon fiber (MCF, 0.8%) were used to modify conventional asphalt to prepare high-viscosity modified asphalt suitable for this purpose. The performance of the modified asphalts was evaluated by conventional index, kinematic viscosity, dynamic shear rheological test (DSR), multiple stress creep recovery test (MSCR), and bending beam rheometer test (BBR). The road performance of the modified asphalt mixtures was evaluated by high-temperature rutting, low-temperature bending, freeze-thaw splitting, fatigue, speckle, anti-skid, and water seepage tests. The results show that increasing the content of SBS can improve the high-temperature deformation resistance, low-temperature failure strain, kinematic viscosity, and viscosity toughness of modified asphalt, and the optimum content of SBS was 6%. SBR can improve the high-temperature performance, kinematic viscosity, and water damage resistance of modified asphalt, and the optimum dosage was 2%. Compared with 5% SBS-modified asphalt mixture, the dynamic stability, low-temperature failure strain, and freeze-thaw splitting strength ratio of 6% SBS + 0.8% MCF composite-modified asphalt mixture were increased by 48.7%, 24.7%, and 5.2% respectively. Compared with the 5% SBS-modified asphalt, the same characteristics of the 2% SBR + 5% SBS + 0.8% MCF composite-modified asphalt increased by 127.1%, 13.5%, and 5.5%, respectively. Compared with 5% SBS-modified asphalt, the fatigue performance of 6% SBS + 0.8% MCF-modified asphalt was improved by 32.2%. The kinematic viscosity of 6% SBS + 0.8% MCF and 5% SBS + 0.8% MCF + 2% SBR modified asphalt met the performance requirements of high-viscosity asphalt and had excellent road performance. It can be applied to ultra-thin overlays to optimize its adhesion with the original pavement.

Experimental Study on the Effect of Fibers on Engineered Cementitious Composite Short Square Columns

Recent earthquakes severely damaged short columns due to high lateral stiffness and low ductility. Some conditions, such as reductions in the heights of some columns compared to others on the same floor, deep beams, partially buried basements, and non-structural walls, cause short column effects. The prominent characteristics of engineered cementitious composites (ECCs) reinforced with polyvinyl alcohol (PVA) fibers – including their high tensile strength, micro and multiple cracks, energy dissipation, high ductility, and strain hardening – lead to improved seismic performance and economic efficiency in structure elements. In this study, 11 ECC columns with different fiber fractions (0–1.5%) and aspect ratios (3–7), as well as one conventional concrete column, were tested and evaluated. The results showed that increasing fiber friction and shear aspect ratio increased the length of the plastic hinge zone and ductility by at least 50% and 100%, respectively. Furthermore, the failure mode changed from brittle shear to ductile shear.

Laboratory Evaluation of the Properties of Dense Graded Asphalt Mixtures Containing Waste Glass Fibre and Crumb Rubber

Due to environmental issues and rising costs of construction materials, there is an increasing desire to use reclaimed asphalt pavement (RAP) material in road construction. However, using too much of this material may lead to impairment of fundamental properties of asphalt mix. Glass fibre material is a well-known modifier and could be used to compensate possible downgrade of properties. Research articles and theoretical material have shown that adding too much fibre glass reinforcement could cause damage to asphalt mixture. Therefore, in this research, reference mixture has been compared to three projected AC 11 surface mixtures with different amount of fibre glass. The same has been done to HMAC mixtures, but in this case, there is crumb rubber used as mixture modifier. Experimental part has shown that using fibre glass in asphalt mixtures for both construction layers may have positive influence on fundamental parameters of HMAC and AC asphalt mixes, which can be a good solvation for using waste glass fibre in road construction.

Systematic Experimental Assessment of POFA Concrete Incorporating Waste Tire Rubber Aggregate.

Several researchers devoted considerable efforts to partially replace natural aggregates in concrete with recycled materials such as recycled tire rubber. However, this often led to a significant reduction in the compressive strength of rubberized concrete due to the weaker interfacial transition zone between the cementitious matrix and rubber particles and the softness of rubber granules. Thereafter, significant research has explored the effects of supplementary cementitious materials such as zeolite, fly ash, silica fume, and slag used as partial replacement for cement on rubberized concrete properties. In this study, systematic experimental work was carried out to assess the mechanical properties of palm oil fuel ash (POFA)-based concrete incorporating tire rubber aggregates (TRAs) using the response surface methodology (RSM). Based on the findings, reasonable compressive, flexure, and tensile strengths were recorded or up to 10% replacement of sand with recycled tire fibre and fine TRAs. In particular, the reduction in compressive, tensile, and flexural strengths of POFA concrete incorporating fibre rubber decreased by 16.3%, 9.8%, and 10.1% at 365 days compared to normal concrete without POFA and rubber. It can be concluded that utilization of a combination of POFA and fine or fibre rubber could act as a beneficial strategy to solve the weakness of current rubberized concrete’s strength as well as to tackle the environmental issues of the enormous stockpiles of waste tires worldwide.