A Textile Waste Fiber-Reinforced Cement Composite: Comparison between Short Random Fiber and Textile Reinforcement

The influence of palm fiber reinforcement on the cement content of vegetated concrete substrate under the condition of equal strength

Vegetated concrete substrate (VCS) is a kind of ecological cemented soil, which has very wide application prospect in high and steep rock slope eco-protection. Cement is an important component of VCS, but it has high energy consumption and environmental pollution. Fiber reinforcement plays an positive role in improving the mechanical properties of soil, and its use as a substitute for cement content in VCS under the condition of equal strength is rarely investigated. In this study, the unconsolidated-undrained (UU) triaxial compression test of unreinforced substrate as blank control samples (BCS) and reinforced substrate as fiber reinforced samples (FRS) were carried out. The test results showed that the stress-strain curve of VCS can be divided into compaction stage, elastic stage, plastic stage and strain hardening stage. The average peak strength increased by 34.3kPa, 53.6kPa, 218kPa and 81.8kPa as cement content of VCS was 0%,4%, 6% and 8%, respectively. The relationship between the peak strength and cement content of VCS could be better fit by Boltzmann function. The mathematical model of fiber instead of cement in VCS under the condition of equal strength was established. It is found that there is a critical point of cement content according to the mathematical model. The cement of VCS can be completely replaced by plam fiber as the cement content is less than the critical point. While the cement content is higher than the critical point, the cement of VCS can be partially replaced by plam fiber. The decrease of average cement content was 17.23%, 19.00%, 24.27% and 25.34% with 0.2%, 0.4%, 0.6% and 0.8% fiber content in reinforced substrate, respectively. The theoretical method and interpolation method for fiber substitute cement content of VCS under equal strength condition were proposed, which can provide technical guidance for ecological slope protection engineering practice of vegetated concrete.

A study on the strength and durability characteristics of fiber-reinforced recycled aggregate concrete modified with supplementary cementitious material

Recycled aggregate (RA) made from waste concrete is an environmentally friendly alternative to natural aggregate (NA) for concrete manufacturing. However, compared to NA concrete, concrete produced with recycled aggregates has poor characteristics. Supplementary cementitious materials (SCMs) can be used to enhance the poor properties of recycled aggregate concrete (RAC). Silica fume and fly ash are commonly used SCMs in the World, but their high usage led to a shortage of silica fume and fly ash. Still, the deficiency of these materials in large parts of the world is a challenge that requires exploring alternative feedstock materials for the construction industry in the coming years. Wheat straw ash (WSA) is an agricultural waste product that could be used as an alternative SCM due to its pozzolanic behavior to enhance the properties of RAC. In addition, concrete is brittle and needs reinforcement, for which polypropylene fibers (PPFs) can be used. The current research examines the mechanical characteristics of fiber-reinforced RAC, including compressive strength, splitting tensile strength, and ductility performance. Durability indicators, such as chloride diffusion, chloride penetration, acid resistance, and water absorption test, were also assessed. The results showed that concrete samples with 10% WSA, 50% RA and 1.5% PPFs had the highest compressive and splitting tensile strength, 60.2 MPa and 7.25 MPa, respectively, representing increases of 24.75% and 30.65%, as compared to plain samples at 56 days. In these samples, water absorption was reduced by 13% due to the finer WSA particles resulting in the lowest reduction in strength and mass recorded when exposing concrete samples to acidic media. The statistical analysis also validated that irrespective of WSA and PPFs, the concrete with 0% RA had the highest performance in strength and durability behavior. The study showed that WSA and PPFs might be employed in tandem to offset the poor behavior of RA, enhance the bond between fibers and concrete, and improve the mechanical strength and durability performance of RAC, thus demonstrating its suitability as a sustainable and economical construction material.

Optimization of seismic performance in waste fibre reinforced concrete by TOPSIS method

For a sustainable environment and to tackle the pollution problem, industrial wastes can be used in concrete composite materials. This is especially beneficial in places prone to earth quack and lower temperature. In this study, five different types of waste fibres such as polyester waste, rubber waste, rock wool waste, glass fibre waste and coconut fibre waste were used as an additive in 0.5% 1%, and 1.5% by mass in concrete mix. Seismic performance related properties of the samples were examined through evaluation of compressive strength, flexural strength, impact strength, split tensile strength, and thermal conductivity. Results showed that, impact strength of the concrete significantly improved by the addition of fibre reinforcement in concrete. Split tensile strength and flexural strength were significantly reduced. Thermal conductivity was also influenced by addition of polymeric fibrous waste. Microscopic analysis was performed to examine the fractured surfaces. In order to get the optimum mix ratio, multi response optimization technique was used to determine the desired level of impact strength at an acceptable level of other properties. Rubber waste was found to be the most attractive option followed by coconut fibre waste for the seismic application of concrete. The significance and percentage contribution of each factor was obtained by Analysis of variance ANOVA (α = 0.05) and pie chart which showed that Factor A (waste fibre type) is the main contributor. Confirmatory test was done on optimized waste material and their percentage. The order preference similarity to ideal solution (TOPSIS) technique was used for developed samples to obtain solution (sample) which is closest to ideal as per given weightage and preference for the decision making. The confirmatory test gives satisfactory results with error of 6.68%. Cost of reference sample and waste rubber reinforced concrete sample was estimated, which showed that 8% higher volume was achieved with waste fibre reinforced concrete at approximately same cost as pure concrete. Concrete reinforced with recycled fibre content is potentially beneficial in terms of minimizing resource depletion and waste. The addition of polymeric fibre waste in concrete composite not only improves seismic performance related properties but also reduces the environmental pollution from waste material which has no other end use.

Strength, Frost Resistance, and Resistance to Acid Attacks on Fiber-Reinforced Concrete for Industrial Floors and Road Pavements with Steel and Polypropylene Fibers

A comparison of the effect of steel and polypropylene fibers on the strength, frost resistance, abrasion, and corrosion resistance in an acidic environment of fiber-reinforced concrete for industrial floors and road pavements was carried out. Steel fibers with a length of 50 mm and a diameter of 1 mm and polypropylene fibers with a length of 36 mm and a diameter of 0.68 mm were used. The amount of steel fiber varied from 15 to 25 kg/m³, and the amount of polypropylene fiber varied from 2 to 3 kg/m³. It has been established that steel fiber more significantly increases the concrete compressive strength, and both types of dispersed reinforcement increase the flexural strength equally by 27-34%. Also, dispersed reinforcement reduces the concrete abrasion resistance by 15-35% and increases its frost resistance by 50 cycles, which helps to improve the durability of industrial floors and road pavements. The use of steel fiber in an amount of 20 kg/m³ and polypropylene fiber in an amount of 2.5 kg/m³ also increases the concrete corrosion resistance in an acidic environment. In general, dispersed reinforcement with both fiber types has approximately the same technological effect concerning the mentioned applications. However, the use of polypropylene fibers is economically more profitable since an increase in the cost of 1 m³ of concrete with steel fiber reinforcement is from $22.5 to $37.5, and an increase in cost with polypropylene fiber is from $10 to $15.

Fabrication of Textile Waste Fibers Aerogels with Excellent Oil/Organic Solvent Adsorption and Thermal Properties

In recent years, the treatment of textile waste has attracted more and more attention around the world. The reuse of textile waste can contribute to the reduction of carbon emissions and the sustainable development of the economy. Herein, we proposed a facile and cost-effective approach to fabricating aerogel by using textile waste fibers as the matrix and polyvinyl alcohol (PVA) and glutaraldehyde (GA) as crosslinking agents. After being modified with methyltrimethoxysilane (MTMS) via chemical vapor deposition, both the interior and exterior of the textile waste aerogels exhibit a hydrophobic property with a water contact angle of up to 136.9° ± 2.3°. A comprehensive investigation of the structure, thermal properties, mechanical properties and oil absorption capacity of this aerogel shows its potential for building insulation and oil spill cleanup. The textile waste fibers aerogels have low density and high porosity, good thermal stability and outstanding heat insulation properties (K_avg. = 0.049–0.061 W/m·K). With a maximum oil absorption value of 26.9 ± 0.6 g/g and rapid and effective oil/water mixture separation, the aerogel exhibits competitive commercial application value.

Influence of Cotton Knitted Fabric Waste Addition on Concrete Properties

Manufacturing cotton knitted fabric apparel generates a substantial amount of production (pre-consumer) waste. One of the ways to alleviate the environmental impact of this is to use the cotton knitted fabric production waste (CKFW) in concrete, which had the simultaneous benefit of reducing the use of virgin aggregate. The aim of this research was to examine the influence of CKFW on concrete properties, and to explore the possible application of this novel material in the construction industry for the production of precast building elements based on its characteristics. An additional goal was to enhance certain properties of concrete and determine the shortcomings of CKFW concrete. A total of 10 mixes were made and tested. CKFW was used at rates of 1.7% and 3.5% of the total mix volume. All mixtures had the same amount of cement, with three mixes having the addition of silica fume. Crushed limestone was used as the aggregate with different aggregate size combinations. Two types of polycarboxylic ether-based superplasticizer were used. The properties of the fresh mix were determined by the slump method. The ultrasonic pulse velocity, dynamic modulus of elasticity, flexural strength and compressive strength were tested on 28-day-old concrete specimens. The σ–δ diagram is also presented in this paper. We learned that the flexural strength of specimens with CKFW addition was increased by up to 38% but the compressive strength was reduced by up to 20% compared to the reference concrete mix. The CKFW mixtures had higher ductility and permeability. Additionally, silica fume had a positive effect on the concretes with a higher percentage of textiles. The percentages of textile waste used in this study affected the density of concrete in a range of 0–2%. Based on the obtained results, we offer recommendations for further tests and possible applications.

Compressive and Thermal Properties of Non-Structural Lightweight Concrete Containing Industrial Byproduct Aggregates

This study aimed to investigate the recycling opportunities for industrial byproducts and their contribution to innovative concrete manufacturing processes. The attention was mainly focused on municipal solid waste incineration fly ash (MSWI-FA) and its employment, after a washing pre-treatment, as the main component in artificially manufactured aggregates containing cement and ground granulated blast furnace slag (GGBFS) in different percentages. The produced aggregates were used to produce lightweight concrete (LWC) containing both artificial aggregates only and artificial aggregates mixed with a relatively small percentage of recycled polyethylene terephthalate (PET) in the sand form. Thereby, the possibility of producing concrete with good mechanical properties and enhanced thermal properties was investigated through effective PET reuse with beneficial impacts on the thermal insulation of structures. Based on the obtained results, the samples containing artificial aggregates had lower compressive strength (up to 30%) but better thermal performance (up to 25%) with respect to the reference sample made from natural aggregates. Moreover, substituting 10% of recycled aggregates with PET led to a greater reduction in resistance while improving the thermal conductivity. This type of concrete could improve the economic and environmental aspects by incorporating industrial wastes—mainly fly ash—thereby lowering the use of cement, which would lead to a reduction in CO₂ emissions.

Frost Resistance Investigation of Fiber-Doped Cementitious Composites

Fibers used as reinforcement can increase the mechanical characteristics of engineering cementitious composites (ECC), but their frost resistance has received less attention. The mechanical properties of various fiber cementitious materials under the dual factors of freeze-thaw action and fiber dose are yet to be determined. This study examines the performance change patterns of cementitious composites, which contain carbon fiber, glass fiber, and polyvinyl alcohol (PVA) fiber at 0%, 0.5%, and 1% volume admixture in freeze-thaw tests. Three fiber cement-based materials are selected to do the compression and bending testing, and ABAQUS finite element modeling is used to assess the performance of fiber cement-based composite materials. The microscopic observation results show that the dispersion of glass and PVA fibers is higher than that of carbon fibers. As a result, the mechanical characteristics of the fiber-doped cementitious composites increase dramatically after freeze-thaw with increasing dosage. The compression test results show the frost resistance of carbon fiber > PVA fiber > glass fiber. In addition, the bending test results show the frost resistance of carbon fiber > glass fiber > PVA fiber. The 3D surface plots of the strength changes are established to observe the mechanical property changes under the coupling effect of admixture and freeze-thaw times. ABAQUS modeling is used to predict the strength of the cementitious composites under various admixtures and freeze-thaw cycles. The bending strength numerical equation is presented, and the bending and compressive strengths of three different fiber-cement matrix materials are accurately predicted.

Recycling of 100% Cotton Fabric Waste to Produce Unsaturated Polyester-Based Composite for False Ceiling Board Application

In recent years, the garment and textile industries generate millions of tons of textile waste every year around the world. Textile wastes are one of the disposed of materials and the sum of disposed of material squander materials expanded from year to year. For this reason, regenerating and utilizing the textile waste item as resources and decreasing environmental pollution may be an extraordinary opportunity. This research is aimed at manufacturing unsaturated polyester composite reinforced with 100% cotton fabric waste for ceiling board application using a manual mixing process followed by the compression molding method. The statistical results showed that mechanical properties of the produced composite samples such as tensile, compressive, flexural, and impact strength are affected by fiber mixed ratio and matrix loading at $\alpha =0.05$ . The composite ceiling reinforced with 33 weight % cotton fabric waste and a matrix of 67 weight % unsaturated polyester had a maximum tensile strength of 198 MPa, the flexural strength of 30.1 MPa, and compressive strength of 1105.3 MPa. On the contrary, the false ceiling board made from 10% cotton fabric waste and matrix of 90% unsaturated polyester had a lower tensile strength of 112.6 MPa, flexural strength of 21.5 MPa, and compressive strength of 867.5 MPa. Generally, the manufactured composites’ mechanical behaviors were comparable to existing commercial ceiling boards and the output of this research work can protect the environmental pollution by reducing textile waste disposed to landfills.

Graphene Oxide/Fe3O4/Chitosan−Coated Nonwoven Polyester Fabric Extracted from Disposable Face Mask for Enhanced Efficiency of Organic Dye Adsorption

Owing to the COVID-19 pandemic, huge amounts of disposable face masks have been manufactured and used, and these discarded face masks have to be treated. In this study, we propose a simple approach for reusing the nonwoven polyester fabric (NWPF) from disposable face masks. In this approach, NWPF is utilized as a supporter for coating of a layer of graphene oxide/Fe3O4/chitosan (GFC) to form a GFC/NWPF adsorbent at room temperature via a simple spray coating method that does not require any solvent. The specific properties of GFC, NWPF, and the GFC/NWPF adsorbent were analysed via X-ray diffraction, transmission electron microscopy, ultraviolet–visible spectroscopy, vibrating sample magnetometry, and field-emission scanning electron microscopy. Results showed that the presence of NWPF enhanced the adsorption capacity of GFC towards organic dyes. At high concentrations of the organic dyes, the adsorption efficiency of the GFC/NWPF adsorbent to the dyes reached 100% within 24 h. The adsorption capacity ( $q_{\max }$ ) of the GFC/NWPF adsorbent to methylene blue, methyl orange, Congo red, and moderacid red was 54.795, 87.489, 88.573, and 29.010 mg g−1, respectively, which were considerably higher than that of bulk GFC (39.308, 82.304, 52.910, and 21.249 mg g−1, respectively).