Percentage Of Fibers Research Articles

Histological Changes in Skin and Subcutaneous Cellular Tissue in Patients with Massive Weight Loss After Bariatric Surgery.

Morbid obesity is a public health problem with high social and economic impact. Due to failure in its treatment with traditional weight loss strategies, surgical interventions are usually required, which give rise to massive weight loss. Until now, the studies made are inconclusive regarding the histological changes in the skin caused by massive weight loss, which may later generate post-surgical complications. Therefore, the objective of this study is to evaluate the cutaneous histological changes before and after bariatric surgery. Two skin biopsies were taken from nine different patients who underwent bariatric surgery. The first biopsy was taken before the surgical intervention, and the second biopsy was taken a year after the surgery and massive weight loss. Histological analysis was performed using haematoxylin & eosin staining, Weigert's Resorcin-Fuchsin, and Masson's trichrome stain to analyse the percentage of collagen fibres, percentage of fibrosis, percentage of vascularity, vascular layer involvement and adipocyte population. The differences between the biopsies were evaluated with the Student's T test and Mann-Whitney U test, with a p-value of <0.05. Biopsies from post-bariatric patients with MWL showed an increase in fibrosis percentage, and a decrease in collagen fibres, elastic fibres of the dermis, adipocyte population, as well as reduced vascular proliferation. MWL after bariatric surgery gives rise to changes in the skin and subcutaneous cellular tissue. Skin shows an increased fibrosis percentage after massive weight loss. Elastic and collagen fibres become disorganized after massive weight loss. Vascular proliferation is decreased after massive weight loss. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Microwave-Assisted Fabrication and Characterization of Carbon Fiber-Sodium Bismuth Titanate Composites

Lead-based piezoelectric materials cause many environmental problems, regardless of their exceptional performance. To overcome this issue, a lead-free piezoelectric composite material was developed by incorporating different percentages of carbon fiber (CF) into the ceramic matrix of Bismuth Sodium Titanate (BNT) by employing the microwave sintering technique. The aim of this study was also to evaluate the impact of microwave sintering on the microstructure and the electrical behavior of the carbon-fiber-reinforced Bi0.5Na0.5TiO3 composite (BNT-CF). A uniform distribution of the CF and increased densification of the BNT-CF was achieved, leading to improved piezoelectric properties. X-ray diffraction (XRD) showed the formation of a phase-pure crystalline perovskite structure consisting of CF and BNT. A Field Emission Scanning electron microscope (FESEM) revealed that utilizing microwave sintering at lower temperatures and shorter dwell times results in a superior densification of the BNT-CF. Raman Spectroscopy confirmed the perovskite structure of the BNT-CF and the presence of a Morphotropic Phase Boundary (MPB). An analysis of nanohardness indicated that the hardness of the BNT-CF increases with the increasing amount of CF. It is also revealed that the electrical conductivity of the BNT-CF at a low frequency is significantly influenced by the amount of CF and the temperature. Moreover, an increase in the carbon fiber concentration resulted in a decrease in dielectric properties. Finally, a lead-free piezoelectric BNT-CF showing dense and uniform microstructure was developed by the microwave sintering process. The promising properties of the BNT-CF make it attractive for many industrial applications.

Effect of Age and Sex on Medullation Types and Fiber Characteristics in Huacaya Alpacas

Background: Fiber is a distinctive attribute of the alpaca due to its softness qualities; it contains less grease and has a finer cuticle compared to sheep's wool. Therefore, the types of medullation were estimated: non-medullated fibers (NoMed), fragmented medulla (FragMed), discontinuous medulla (DiscMed), continuous medulla (ContMed) and strongly medullated fibers (StrMed), considering the age and sex of Huacaya breed alpacas (Vicugna pacos) under extensive management conditions in high Andean pastures. Methods: Six grams of fiber samples were collected from the mid-side region (located above the third last rib, halfway between the midline of the belly and the midline of the back) of 240 Huacaya alpacas from the district of Macusani, province of Carabaya, Puno, during the year 2022. They were then processed in the Fiber Laboratory of the Faculty of Textile Engineering and Garments at the National University of Juliaca using the FIBER EC V4.0 and FIBER MED V1.0 equipment. Result: The results obtained show that the percentage of non-medullated fibers decreases as the animal’s age increases (1 year= 75.60%, 2 years=69.43%, 3 years=69.05% and greater than 4 years=66.25%) (P≤0.05). The percentage of medullated fibers in animals of 1 year was 24.40%; 2 years, 30.57%; 3 years, 30.95% and greater than 4 years, 33.59% (P≤0.05). The mean fiber diameter in 1-year-old alpacas is 17.32 mm, 2 years=19.49 mm, 3 years = 19.91 mm and 4 years=20.10 mm (P≤0.05). The comfort factor in 1-year-old animals is 99.47%, 2 years with 98.02%, 3-year-olds with 97.01% and those older than 4 years with 96.45% (P≤0.05). Regarding the curvature index, values of 55.86 °/mm were obtained for 1-year-old animals, 53.43 °/mm for 2-year-olds, 53.99 °/mm for 3-year-olds and 52.23°/mm for those older than 4 years (P≤0.05). In conclusion, Huacaya alpacas exhibit low values for the percentage of strongly medullated fibers due to the age and sex of the animal, demonstrating very good fleece uniformity.

Characterization of Taguchi optimized fiber reinforced copper slag concrete composites with strength properties

Establishing the ideal design has always been a difficulty for concrete engineers because of the inclusion of many alternative construction materials particularly when dealing with the incorporation of slag elements and fibers in concrete mix design. In this study, the Taguchi optimization method is implemented to predict the optimal mix design of fiber reinforced copper slag aggregate concrete (FRCSC) with mechanical strength properties. For this purpose, different parameters influencing mechanical strength were defined based on the available literature. The Taguchi approach was subsequently applied to develop an orthogonal array of parameters, and experimental tests were carried out in accordance with the suggested design array to acquire experimental data for each and every strength property. Three major influencing parameters like fiber length (FL), fiber percentage (FP), and copper slag content (CS) were considered in order to get optimal mix design for FRCSC. Analysis of variance was also employed to evaluate the effective factors on compressive, split-tensile, flexural, water absorption and void content properties for FRCSC. It was found that the proposed method was effective in finding the optimal mixture design from strength point of FRCSC and the experimental results indicated a significant improvement in five selected strength properties of FRCSC. From the results of Taguchi analysis, it can be concluded that, for five selected strength properties, 60% CS + 1% of fiber + 20 mm of fiber length is the optimal mix design combination for FRCSC. Finally, physical and microstructural characterization through FESEM and EDX were carried out to have a closer justification for the test results.

PMMA-induced biofilm promotes Schwann cells migration and proliferation mediated by EGF/Tnc/FN1 to improve sciatic nerve defect

ObjectiveThe purpose of this study is to investigate the role of PMMA-induced biofilm in nerve regeneration compared with silicone-induced biofilm involved in the mechanism. MethodsPMMA or silicon rods were placed next to the sciatic nerve to induce a biological membrane which was assayed by PCR, Western blot, immunohistochemistry, immunofluorescence and proteomics. A 10 mm sciatic nerve gaps were repaired with the autologous nerve wrapped in an induced biological membrane. The repair effects were observed through general observation, functional evaluation of nerve regeneration, ultrasound examination, neural electrophysiology, the wet weight ratio of bilateral pretibial muscle and histological evaluation. Cell proliferation and migration of Schwann cells co-cultured with EGF-treated fibroblasts combined with siRNA were investigated. ResultsThe results indicated that expression of GDNF, NGF and VEGF along with neovascularization was similar in the silicone and PMMA group and as the highest at 6 weeks after operation. Nerve injury repair mediated by toluidine blue and S100β/NF200 expression, the sensory and motor function evaluation, ultrasound, target organ muscle wet-weight ratio, percentage of collagen fiber, electromyography and histochemical staining were not different between the two groups and better than blank group. EGF-treated fibroblasts promoted proliferation and migration may be Tnc expression dependently. ConclusionOur study suggested that PMMA similar to silicon induced biofilm may promote autogenous nerve transplantation to repair nerve defects through EGF/Tnc/FN1 to increase Schwann cells proliferation and migration.

Changes in the physical, chemical and sensory properties of pasta made by partially substituting wheat flour with black glutinous rice flour

Black glutinous rice flour (BGRF) had the potential to be used as a wheat substitute to increase the health-promoting nutritional value of pasta products. The purpose of this study was to investigate the possibility of using BGRF as an alternative to wheat flour in the production of pasta to improve its nutritional value. The research explored the physical, chemical, sensory properties, and consumer acceptance of pasta formulations with 0%, 20%, 40%, and 60% BGRF substitution. The findings revealed that pigmentation of BGRF contributed to increased phenolic compounds and antioxidant properties, which impacted physical and chemical properties of the pasta. The results indicated that a 40% substitution of BGRF was well-liked by consumers, while a 60% substitution led to decreased acceptance. The physical properties of uncooked pasta (UC-PAS) and cooked pasta (CK-PAS), such as moisture content and color values, were significantly influenced by the percentage of BGRF substitution. Specifically, the moisture content of UC-PAS decreased with higher BGRF substitution, resulting in changes in color values. These changes included an increase in redness, as well as a decrease in lightness and yellowness. Additionally, the pigmentation of BGRF contributed to increased phenolic compounds and antioxidant properties, which affected physical and chemical properties of the pasta. The pasta’s cooking quality, including cooking time (CKT), cooking loss (CKL), and cooking yield (CKY), also showed significant differences with varying percentages of BGRF substitution. Furthermore, the proximate composition indicated that the percentages of ash, protein, fat, and fiber increased as the proportion of BGRF increased, with pasta containing 60% BGRF demonstrating the highest values for these properties. All these findings provide evidence that BGRF substitution had a significant positive impact on the physical, chemical, and sensory properties of pasta. For example, the pasta had better antioxidant properties and was well-accepted by consumers. The potential for enhancing the nutritional profile of pasta products by substituting wheat flour with BGRF is noteworthy. Key words: black glutinous rice, wheat, rice flour, pasta, antioxidant, bioactive compounds

Effects of planting date and density on cotton cultivars in sub‐Saharan Africa rainfed conditions: A case study in Mali

AbstractMali is among Africa's three biggest cotton (Gossypium hirsutum L.)‐producing countries, and cotton growing is the principal driving force behind Mali's agricultural sector. Cotton production is rainfed on small‐scale family farms as a commercial crop alongside staple crops grown for subsistence. Cultivar choice, planting date, and planting density are critical elements for seed cotton yield that should be optimized. This study aimed to understand the interactions between planting dates and planting densities for the optimal production of four cotton cultivars in Mali. Two trials were set up in two seasons at the Finkolo and N'Tarla research stations. A split‐plot design with four replications was used, with planting dates (early and delayed by 3 weeks) as the main plots and planting density (41,666; 83,333; and 166,666 plants/ha) and cultivar (Malian NTA MS334, Togolese STAM 129A, Australian SIOKRA L23, and Brazilian BRS 293) as the subplots. In 2021, seed cotton yield was 1263 kg/ha for early planting versus 361 kg/ha for late planting. Medium and high planting densities produced the same yield level, higher than the low planting density. Regardless of the planting density, early plantings' average capsular weight and seed index were higher than those of late plantings. The African cultivars (STAM 129A and Malian cultivar NTA MS334) were the most productive. Due to significant interactions on fiber percentage and to optimize cotton yields in Mali, planting should be early, with planting densities higher than 41,666 plants/ha, and either of the African cultivars tested should be used.

EXPERIMENTAL EVALUATION OF EXPANSIVE SOIL STABILIZED WITH WHEAT HUSK ASH AND SISAL FIBER

Everything starts with soil. Being a civil engineer, we are aware of how essential soil is to construction, as everything is dependent on it. Before building any kind of structure on top of soil, we examine the soil's characteristics and behavior to determine its strength and ability to support the weight of the structure to be built on top of it. In this study work, we used agricultural waste materials, such as wheat husk ash (WHA), as a stabilized material in soil at different percentages of 5%, 10%, and 15% to perform various tests on the soil to determine its qualities or strength. Sisal fibers are inexpensive, readily available locally, and environmentally benign, making them an excellent choice for enhancing soil properties. The stabilizing effect of sisal fiber on soil characteristics has been experimentally investigated in this work. In light of this, an experimental study is carried out using pricey, locally accessible soil that has been blended with various percentages of sisal fiber. In the CBR mold and UCS sampler, soil samples are prepared at their maximum dry density (MDD) matching to their optimum moisture content (OMC) both with and without Sisal Fiber and WHA. In the laboratory, CBR and UCS tests are carried out in accordance with the proportion of Sisal Fiber by dry weight of soil, which is determined to be 1%, 1.5%, or 2%. According to test results, the amount of sisal fiber in the soil increases with its saturated CBR and UCS value. When wheat husk ash and sisal fiber are added, the CBR of the mix increases and the pavement thickness decreases, resulting in lower construction costs and ultimately, more economical highway building. Key Words: Compaction test, CBR, UCS, WHA, Sisal Fiber

Natural Lime–Cork Mortar for the Seismic and Energetic Retrofit of Infill Walls: Design, Materials, and Method

Recent seismic events have prompted research into innovative and sustainable materials for strengthening and repairing obsolete and vulnerable buildings. These earthquakes have exposed the high seismic vulnerability of existing reinforced concrete (RC) buildings, particularly in secondary structural elements like infill walls. In addition to structural issues, these buildings often face significant energy deficiencies, such as thermal bridges, due to inadequate insulation. Traditionally, structural and energy improvements for residential buildings are addressed separately with different methods and protocols. This preliminary study is part of a broader research initiative at the University of Reggio Calabria (Italy), aiming to design an innovative fiber-reinforced plaster using natural, sustainable, and locally produced materials to enhance the energy and structural performance of existing wall infills. The study investigates two plaster matrices made of natural hydraulic lime and silica sand, with 15% and 30% cork granules added. Mechanical and thermophysical tests on multiple specimens were conducted to evaluate their suitability for seismic and energy retrofitting of infill walls. Results indicate that adding cork reduces mechanical strength by approximately 42% at a 30% cork content without compromising its use in seismic retrofitting. Thermophysical tests show improved thermal performance with a higher cork content. These findings suggest that the lime–cork mixture at 30% is effective, offering excellent ductility and serving as a promising alternative to traditional cementitious plaster systems. The next experimental phase will test matrices with varying percentages of gorse fiber.

Constitutive modeling and extended performance evaluation of concrete reinforced with non-hybrid waste tire steel fibers

This paper investigates the extended performance and constitutive modeling of waste tire steel fiber reinforced concrete (WFRC), making notable contributions to civil engineering materials. The study assesses constitutive modeling, reinforcement indices, and the long-term performance of concrete reinforced with varying percentages of waste tire steel fiber (WSF) ranging from 0.30 % to 1.75 %. A modified analytical model for predicting compressive stress-strain curves of WFRC is introduced and compared with previous analytical models for fiber-reinforced concrete. Additionally, a novel waste tire steel fiber reinforcing index, based on WSF properties, is proposed. Empirical relationships between strength properties and reinforcement indices are established. Experimental strength properties at the standard age, as well as water absorption, carbonation depth, and split-tensile strength of specimens aged beyond the standard age at 600 days and fiber-matrix interaction obtained by SEM analysis, are reported. Prediction models are proposed for estimating the mechanical properties of WFRC at the standard age, with results compared against existing codes. The proposed modified analytical model for the uniaxial compressive stress-strain curve demonstrates better coherence with experimental curves than existing models. Furthermore, empirical equations developed in terms of the waste tire steel fiber reinforcing index demonstrate satisfactory alignment between predicted and experimental strength properties. Significant improvements are observed in specimens aged 600 days, indicating the promising role of WSF in enhancing the long-term performance and serviceability of structures. Further studies are recommended to explore the performance of WFRC in aggressive environmental conditions.

Effect of wetting/drying cycles on the durability of flax fibers reinforced earth concrete

Earth concrete is composed of fine particles which make them very sensitive to humidity and affects their long-term durability. In this study, the effect of wetting/drying cycles on earth concrete according to ASTM D559 was studied by measuring the weight loss, pH, and Electrical Conductivity (EC). The effect of different percentages of flax fibers was investigated. The residual properties of reference specimens and earth concrete specimens subjected to wetting/drying cycles were evaluated by conducting compressive tests at the end of the 25 cycles. Ultrasound, Acoustic Emission (AE), and Digital Image Correlation (DIC) techniques were applied to estimate the concrete progressive deterioration during and at the end of the 25 wetting/drying cycles. The results showed that earth concrete degradation begins during the first cycle with visible cracks on the surface of the specimens. The mechanical tests showed a considerable loss of earth concrete mechanical properties after 25 cycles. The ultrasonic test showed that the degradation rate was more important for specimens without flax fibers. The cumulative acoustic activity was effectively used to assess the different damage progression phases and crack propagation. The signal parameters (energy, amplitude, etc.) evolution indicates premature damage for earth concrete specimens subjected to wetting drying cycles.

Effect of steel fibers on the interfacial shear strength of flyash and GGBS based geopolymer concrete activated with water glass

Concrete, a fundamental construction material, heavily relies on cement, manufacturing process of cement results in significant CO2 emissions, posing environmental concerns. Hence, exploring substitutes for cement becomes imperative to mitigate CO2 emissions. Geopolymer materials emerge as promising alternatives capable of entirely replacing Ordinary Portland Cement (OPC). However, these materials necessitate activators to initiate the polymerization reaction. While Na2SiO3 and NaOH are commonly utilized as activators, their cost-effectiveness is questionable. Moreover, when Ground Granulated Blast Furnace Slag (GGBS) reacts rapidly with these activators. To address these issues and streamline concrete production, “water glass” is employed as an activator, offering a solution to avoid rapid setting and economize the production process. In other hand the production of mass concrete structures, interfaces and joints critical points where cracks may develop. To ensure monolithic behavior, shear ties were advised at the interface in order to establish strong bond strength. However, the efficiency of construction could be decreased by adding more shear ties. The purpose of this study is to evaluate the interfacial shear strength of Geopolymer concrete (GPC), With the addition of different percentages of steel fibers 0.5, 1%,and 1.5%, with shear ties at the interface of push-off specimens. The findings reveal that it is viable to replace two shear ties with one 8 mm-2L shear tie and 1% crimped steel fibers of 30 mm length.

Understanding fiber quality in field-grown shaded cotton: Nitrogen fertilization implications

ContextHigh nitrogen rates are important to field-grown cotton (Gossypium hirsutum L.) for recovering from stresses such as light restriction and alleviating its negative impact on yield. However, there is little information on its influence on fiber quality after shading. ObjectiveThe objective of this study was to examine fiber quality responses to nitrogen fertilization of shaded cotton. MethodsCotton plants were exposed to a 42 % reduction in global radiation for 16–25 days during early flowering, and fertilizer with different N rates in the Center-West (Primavera do Leste - PL and Chapadão do Sul - CS) and Southeast (Itapeva - IT) Brazil. Four N rates were used in PL and IT, and 3 N rates and an early (FM 906GLT) and a late-cycle (FM 983GLT) cotton cultivar were used in CS. Fiber quality from bolls taken from entire plots (nonportioned plants) and from the lower, middle, and upper thirds of the canopy (portioned plants) was assessed. ResultsThe lack of interaction in most analyses indicated shading and nitrogen effects on fiber quality as independent. Shading resulted in occasional effects on micronaire, strength, length, length uniformity, and short fiber index. Micronaire of nonportioned plants decreased in response to N inputs, wherein values at the maximum N rate were lower than those at the minimum one by 5.21 % and 7.91 % in PL and IT, respectively. Increasing N rates also decreased micronaire in all canopy portions in IT and the lower third in CS but had nonconclusive effects on other fiber properties. Fiber length and strength were generally greater in the late-maturing cultivar, which had higher micronaire readings in the lower third of the canopy and lower readings in the upper canopy compared with the early cultivar. ConclusionsIn conclusion, shading during early flowering has limited and inconsistent effects on cotton fiber quality. Conversely, N fertilization leads to more predictable results, so higher N rates increase the risk of heightened immature fiber percentage. ImplicationsThe findings of this work provide new insights into how nitrogen fertilization management affects cotton fiber quality. Future research should consider other management techniques, such as the timing of the crop termination, to avoid the occurrence of low micronaire.

Experimental Studies on Fiber Reinforced Soil Stabilized with Lime and Fly Ash

This study investigates the enhancement in strength of fiber-reinforced soil stabilized with lime and fly ash, focusing on key parameters essential for highway design and construction i.e., California Bearing Ratio (CBR) and compaction characteristics. Laboratory tests were conducted to determine the CBR values, Maximum Dry Density (MDD), and Optimum Moisture Content (OMC) of soil stabilized with varying percentages of fly ash (FA) and lime, and reinforced with different types and percentages offibers, specifically coir fibers (CF) and polypropylene fibers (PF). The addition of stabilizing agents (fly ash and lime) to the fiber-reinforced soil was found to increase the OMC and decrease the MDD. Notably, a significant increase in the CBR value was observed up to an optimum content of these admixtures. However, adding fibers beyond a certain percentage resulted in the sample breaking. This study is novel in its comprehensive evaluation of both natural (coir) and synthetic (polypropylene) fibers in combination with traditional stabilizers (fly ash and lime), offering insights into the optimal mix for enhancing soil strength. The findings contribute to more efficient and durable highway construction practices by identifying the balance between fiber reinforcementand chemical stabilization.

Fabrication and characterization of natural fiber reinforced cowpea resin-based green composites: an approach towards agro-waste valorization.

A paradigm shift towards using bio-resins or bio-derived resins among materials scientists has led to wide exploration of the sector. Polymers such as soy protein isolate, poly(hydroxy alkanoate), poly(lactic acid), and thermoplastic starch are all synthetically modified bio-based resins and are costly. The cowpea-derived resin with the least chemical modification was used in this study as a matrix for the formation of composites with natural fibers at a lesser cost. Fabrication of composites of vetiver and jute with varying weight percentages of fiber (50, 60, and 70%) in the innovative cowpea resin resulted in favorable mechanical properties and degradability. The tensile strength was the highest for the jute-cowpea composite (JCP2) at around 37.49 MPa, which also has a flexural strength of 40.3 MPa. Dynamic mechanical analysis of composites reflects the moderate storage moduli of 1802 MPa for JCP2 and 1351 MPa for vetiver-cowpea (VRCP2) composites. Impact strength studies and thermal stability also show optimistic results. The contact angle, water absorption behavior, and swelling in thickness show the moderate hydrophobicity of the composites. This is also a reason for the improved degradability of the composites in soil-burial and microbial environments. Characterizations such as FE-SEM and FTIR spectroscopy, conducted after the degradation of the samples, showcased the level of deterioration. All these results suggest using the innovative cowpea resin as a good alternative to various other synthetic thermoplastic resins used in the fiber reinforced composite manufacturing field.

Mandible development under gestational protein restriction: cellular and molecular mechanisms.

Insufficient evidence regarding how maternal undernutrition affects craniofacial bone development persists. With its unique focus on the impact of gestational protein restriction on calvaria and mandible osteogenesis, this study aims to fill, at least in part, this gap. Female mice were mated and randomized into NP (normal protein) or LP (low protein) groups. On the 18th gestational day (GD), male embryos were collected and submitted to microtomography (µCT), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), PCR, and autophagy dynamic analyses. The study shows that the LP offspring exhibited lower body mass than the NP group, with µCT analysis revealing no volumetric differences in fetus's head. EDS analysis showed lower calcium and higher phosphorus percentages in mandibles and calvaria. SEM assessment evidenced higher hydroxyapatite crystal-like (HC) deposition on the calvaria surface in LP fetus. Conversely, lower HC deposition was observed on the mandible surface, suggesting delayed matrix mineralization in LP fetuses with a higher percentage of collagen fibers in the mandible bone. The autophagy process was reduced in the mesenchyme of LP fetuses. PCR array analysis of 84 genes revealed 27 genes with differential expression in the LP progeny-moreover, increased mRNA levels of Akt1, Mtor, Nfkb, and Smad1 in the LP offspring. In conclusion, the results suggest that gestational protein restriction anticipated bone differentiation in utero, before 18GD, where this process is reduced compared to the control, leading to the reduction in bone area at 15 postnatal day previously observed. These findings provide insights into the molecular and cellular mechanisms of mandible development and suggest potential implications for the Developmental Origins of Health and Disease (DOHaD).

Experimental study of the effect of the addition of Posidonia Oceanica fiber on the thermal and acoustic insulation properties of plaster

In this work, plaster and natural Posidonia Oceanica (PO) fibers are combined to create a composite material that was recently produced. This work’s primary objective is to assess the mechanical and thermophysical performance of the composite material in order to determine whether or not it may be used as a thermal and acoustic insulation material in buildings. For this end, prismatic and parallelepipedic specimens of different dimensions were made with fiber percentages ranging from 0% to 20%. In addition, parallelepiped panels (600 mm × 600 mm × 40 mm3) were also prepared containing 10% of PO fibers. Mechanical properties (flexual strength, compressive strength), thermal properties and sound absorption coefficient were investigated. For each test specimen, the density was calculated for a proportion of fibers ranging from 0% to 20%. The results indicated a marked improvement in the compressive and flexural strength of the fiber-reinforced mixtures. This improvement is respectively 14.5% and 33.8% for mixtures containing 10% of PO fibers. Additionally, the addition of PO fibers significantly decreases density (by 40.5%), thermal conductivity (by 68.5%) and thermal diffusivity (by 36.9%) of the different mixtures. The ideal mechanical characteristics are attained when 5%–10% of the volume is made up of Posidonia Oceanica fibers. The results of the sound absorption coefficient test show that the mixture of plaster with 10% fibers has a good sound absorption coefficient of 0.78 for high frequencies between 1000 Hz and 4000 Hz. This work has shown conclusively that the incorporation of PO fibers, up to a maximum of 10% with plaster, makes it possible to obtain a lightweight composite that can potentially be used as a new insulating construction material.

Effect of para-wood ash and calcium carbonate on the properties of eco-friendly self-compacting mortar reinforced with electronic waste fibers

This paper deals with reducing CO2 emissions from cement production and finding alternative uses for electronic waste (E-waste) fibers in some innovative applications in self-compacting mortar (SCM). In the present research, an attempt has been made to establish the optimum incorporation of E-waste fiber into SCM by varying the fiber content from 5 % to 25 %, combined with para-wood ash and calcium carbonate as supplementary cementitious materials. In this laboratory study, the mix design had a constant water-to-powder ratio of 0.35 and a cement content of 550 kg/m³. Additionally, 20 % of the cement volume was replaced by 10 % para-wood ash and 10 % calcium carbonate. The results indicated a continuous increase of the mini-slump values from 255 mm for the control mix to 270 mm for the mix with the highest fiber content. Mini V-funnel flow times increased from 3.63 to 8.83 s as the fiber content increased. Lower fiber contents of 5 % improved compressive strength because they had a reinforcing role in the matrix of SCM besides the microcrack-bridging role. Higher contents of 10–25 % decreased the strength due to the clustering of fibers and resulting voids. SEM analysis at 28 days showed increased voids with higher percentages of E-waste fibers and para-wood ash alone. The results underline that optimizing fiber content is critical in balancing workability and mechanical properties, and 5 % e-waste fiber content can be considered optimal for enhancing the performance of SCM. This work also creates part of sustainable construction practice with the green solution required to reduce CO2 emissions and work accumulation against E-waste.

Mechanical properties of Kenaf textile-reinforced concrete

This study aims to evaluate the mechanical characteristics of Kenaf Textile Reinforced Concrete (KTRC) specimens to address the growing interest in sustainable construction materials. The research investigated various parameters, including modulus of rupture, total toughness, and toughness indices, while also exploring the impact of polypropylene (PP) chopped – fibre, the number of textile layers (3 and 5), and their arrangement (symmetric and asymmetric) on the mechanical properties of KTRC. The results demonstrated that Kenaf meshes could be used as natural and cost-effective reinforcement in TRC. Increasing the number of reinforcement layers significantly enhanced total energy absorption, and the combination of chopped fibre and Kenaf meshes contributed to maintaining the crack strength of the composites. The results of the three-layer specimens demonstrate that as the percentage of PP fibres increases from 0% to 0.5% and 1%, there is a noticeable increase in toughness compared to the reference samples. Specifically, the toughness of the samples increased by 978.6, 1381.1, and 1520.7, respectively. Eventually, the behavior of the specimens until the moment of complete rupture mostly depends on the number of layers in the thickness of the specimen.

The Mechanical Characteristics of Enhanced Bendable Concrete By Polyvinyl Alcohol Fibers

Abstract Engineered Cementitious Composites (ECC), which are alternatively referred to as Bendable Concrete, is a class of Ultra-ductile cementitious composites characterized by their remarkable ductility and polyvinyl alcohol fiber (PVA) fiber reinforcing. These composites are designed to regulate cracks width effectively. This study investigates the influence of matrix flowability, fiber mixing technique, and curing conditions on the mechanical characteristics of Bendable Concrete utilizing high-tenacity (PVA) fibers. This study examined the compressive strength of Bendable concrete, which ranged from 60 to 70 MPa, with a strain exceeding 3%. To regulate the flowability of the matrix, high range water reducing admixture (HRWRA) was added to a matrix with a weight ratio of silica fume was 10% by weight of cement, a weight ratio of water to cementitious material of 0.3, also polyvinyl alcohol acetate solution (PVAS). The primary parameter under investigation in this study is the changing volume fraction dose of (PVA) fiber, while the remaining materials of the combination were held constant. Four different (PVA) fiber percentages (0.5, 1.0, 1.5, and 2.0)% were adopted by volume of cement. Three (cubes, cylinders, and prisms) were fabricated and cast from each mixture and tested at the ages (7, 28, and 90) days for investigated (compressive, splitting tensile, and Modulus of Rupture) strength, respectively. The results of the tests demonstrated that the proportion of fiber substantially affects the strengths, where both the Compressive strength and Splitting tensile strength were increased with the increment of fiber content until 1% of (PVA) fiber . In comparison, the higher Modulus of Rupture was abtained at 2% (PVA) fiber.