Polyvinyl Alcohol Fibers Research Articles

Self-Healing Characteristics of Polyvinyl Alcohol-Fiber-Reinforced Hot Mix Asphalt for Enhanced Pavement Durability

Pavement maintenance presents significant financial challenges, driving researchers to explore innovative approaches that can prolong pavement service life and reduce costly interventions. The objective of this research is to examine the feasibility of utilizing polyvinyl alcohol (PVA) fibers to self-heal asphalt pavements. A comprehensive mechanical testing strategy was developed to evaluate the self-healing capability of several hot mix asphalt (HMA) mixtures at the micro- and macro-level. Moreover, to assess the healing behavior of macro fractures in PVA-fiber-reinforced HMA, semi-circular bending (SCB) specimens were loaded until peak load and then allowed to heal at varying time intervals and temperatures for several loading cycles. Healing indices developed based on SCB stiffness, strength, and beam fatigue technique were utilized to measure the self-healing ability of control and reinforced mixtures. By comparing different concentrations of PVA fibers with a control HMA, the optimal fiber dosage was determined based on newly developed healing indices. This study also investigated the impact of healing time and different temperatures on healing. The results demonstrated that PVA fibers expedited the healing process, effectively healing macro-, meso-, and micro-cracks. The most effective recovery occurred with 0.3% fiber content at 40°C for a 2 h duration. Incorporating PVA fibers into asphalt pavements presents a promising solution for extending pavement service life and can be helpful in reducing maintenance costs.

Investigation on mechanical behavior of engineered cementitious composites incorporating alkali‐resistant glass fiber and quarry dust

AbstractAt present, engineered cementitious composites (ECC) are rapidly replacing ordinary concrete in the building production due to its superior durability and mechanical qualities. Enormous researches have been done on ECC incorporating various fibers, industrial wastes, supplementary cementitious materials and super plasticizers. As far as fiber is concerned, poly vinyl alcohol fiber was widely explored. In this study, attempt has been made to involve alkali resistant glass fiber as a replacement for poly vinyl alcohol fiber. In addition, the high rate related with ECC as a result of the utilization of micro‐sized silica sand has restricted its extensive pertinences. Thus, this study recommends utilization of quarry dust to replace fine silica sand in the ECC at amounts ranging from 0% to 100% in order to establish a green, sustainable and cost‐effective ECC. The flowability and mechanical demeanor of the ECC mixtures in terms of the tensile, compressive and flexural properties were evaluated. It is arrived that 2% of volume fraction would be the optimum dosage by which better mechanical properties can be achieved. As a result of the present research findings, it is found that the quarry dust could be a better substitute for silica sand up to 75% without any compromise in compressive and flexural strengths. To attain higher tensile qualities, however, it might not be appropriate to replace more than 50% of the silica sand with quarry dust. Cost analysis of the ECC mixtures show that using quarry dust as aggregate is both cost‐effective and sustainable.

Compressive performance and analytical modeling of early strength seawater sea sand engineered cementitious composites

Early strength seawater and sea sand engineered cementitious composites (ESSECC) are novel fiber-reinforced cementitious composites that exhibit strain-hardening behavior and a high early strength. The compressive properties of ESSECC with different polyvinyl alcohol (PVA) fiber content, carbon nanotubes (CNTs) content, and water–binder ratios were investigated at different curing ages in this study. Experimental evaluations were conducted to assess compressive strength, elastic modulus, Poisson's ratio, peak strain, energy dissipation capacity, toughness index, and stress-strain curves. The experimental results showed that early strength of ESSECC reached 58.0 %, 81.6 %, and 86.7 % of its 28-day compressive strength after 2 h, 3 days, and 7 days of curing, respectively. An increase in the PVA fiber volume fraction from 0 to 2 % resulted in a 32.8 % increase in average peak strain. Incorporating 0.15 % CNTs into ESSECC led to an average enhancement of compressive strength by 7.2 %. Based on these experimental results, an analytical model considering the effects of curing age and the addition of PVA fibers and CNTs was developed to describe the compressive stress–strain behavior of ESSECC. This model showed strong consistency with the experimental results.

Synergistic self-healing effect and mechanism of fiber and biological capsule on mortar cracks

In this paper, biological capsules were prepared with volcanic rock particles as bacterial carriers, while water glass and low alkaline sulphoaluminate cement were used as shell materials. The self-healing effect and mechanism of mortar samples prepared with Polyvinyl alcohol (PVA) fibers and biological capsules were studied. The results showed that the samples had the best crack-healing effect after adding PVA fibers and biological capsules. The cracks (<400 μm width) were completely healed. Calcite-type CaCO3 was identified as the primary healing product with irregular and square crystals. In addition, the formation rate of healing products was analyzed by measuring the changes in Ca2+ concentration and pH value in the curing solution. The three-dimensional morphology of healing products attached to the PVA fibers was obtained by laser scanning confocal microscope. Finally, the cementation mechanism between calcite and C-S-H was studied by molecular dynamics simulation. Highlights: The crack healing mechanism of fibers and biological healing agents was studied. The relationship between ion concentration, pH and crack healing was clarified. The cementation mechanism between cracks and mineralized products was revealed.

Production of AlN/CNT reinforced PVA nanofibers as a thermal conductive net for thermal interface applications

The amount of heat generated by electronic components is increasing daily, in line with their growing power and performance. Consequently, there is a heightened demand for thermal interface materials for enhanced cooling of electronics. This study employs a novel approach to fabricate a nano composite thermal interface material on copper substrates to address this challenge. The thermal interface coatings, consisting of carbon nanotubes (CNT) and aluminum nitride (AlN)-reinforced polyvinyl alcohol (PVA) nanofibers with and without an epoxy resin matrix, are fabricated using the electrospinning technique. The findings demonstrate the successful fabrication of a 2.5 µm-thick CNT/AlN-PVA nanocomposite fiber mat coating with an average fiber diameter of 318 nm onto copper substrates. Scanning electron microscope (SEM) images revealed that the AlN particles and CNTs penetrated the fibers. The successful incorporation of AlN particles into PVA fibers was also verified by the Fourier-transform infrared spectroscopy (FT-IR) spectrum of CNT/AlN-PVA nanofibers. No major weight loss was observed in the thermogravimetric (TG) analysis curves up to 200 °C, indicating the thermal stability of coatings. The thermal diffusivity of the copper substrate coated with the CNT/AlN-PVA nanocomposite fiber mat was measured at 36.6 mm2/s. Moreover, the developed CNT/AlN-PVA nanocomposite fiber mat was also applied on top of the fire-retardant epoxy resin-coated copper substrate, which is conventionally used in electronic devices to provide electrical insulation. SEM images revealed that the existence of an epoxy layer on top of copper substrates did not alter the fiber formation during the electrospinning process, and an approximately 2.5 µm-thick CNT/AlN-PVA nanofiber mat was effectively embedded in the epoxy layer after a 1-hour electrospinning process. The thermal diffusivity of the resulting epoxy matrix CNT/AlN-PVA nanofiber reinforced nanocomposite coating is determined to be 7.792 mm2/s, which is 30-fold higher compared to the thermal diffusivity of neat epoxy resin coatings (0.254 mm2/s).

Tensile properties and constitutive model of cost-effective multiscale hybrid fiber reinforced strain hardening cementitious composites

To enhance the mechanical properties and cost-effectiveness of conventional polyvinyl alcohol fiber reinforced strain hardening cementitious composite (PVA-SHCC), a modified version called multiscale hybrid fiber reinforced SHCC (MsHySHCC) was developed. This new composite incorporates a combination of steel fiber, PVA fiber and calcium carbonate (CaCO3) whisker. Uniaxial direct tensile behaviors (stress-strain relationship, tensile strength, tensile deformation capacity and tensile toughness) of designed MsHySHCCs were investigated and evaluated. The results show that the PVA fibers dominate the ductile behavior and the steel fibers and CaCO3 whiskers effectively affect the strength of MsHySHCCs. The PVA fibers can be partially replaced by CaCO3 whisker and steel fiber, along with an increase in tensile strength and ductility of designed composites. The findings suggest that the configuration of MsHySHCC proves to be a viable approach in simultaneously enhancing the strength and ductility of PVA-SHCC. A semi-theoretical prediction model for tensile constitutive relationship was derived. The comparison of the theoretical results with the experimental data shows that this semi-theoretical model is applicable for determining the tensile constitutive relationship of PVA-SHCCs and MsHySHCCs.

Development of low-cost engineered cementitious composites using Yellow River silt and unoiled PVA fiber

One of the main problems for restricting the extensive practical application of Engineered Cementitious Composite (ECC) is its expensive price due to the incorporation of high-price fine quartz sand and polyvinyl alcohol (PVA) fibers. To address this defect, the replacement with solid waste fine aggregate and locally produced PVA fiber has been proved to be a good choice. This work aims to develop low-cost green ECC using Yellow River silt as fine aggregate and locally produced unoiled PVA fiber. The effects of water-binder ratio, sand-binder ratio, and PVA fiber content on the mechanical characteristics of as-prepared ECC were evaluated by a comparative experiment. It has been indicated that the mechanical characteristics of as-prepared low-cost ECC are significantly affected by water-binder ratio, sand-binder ratio, and PVA fiber content. As the water-binder ratio rises, the tensile ductility of as-prepared low-cost ECC gradually increases, but the tensile strength, compressive strength, and flexural strength all decrease. The compressive strength and flexural strength exhibit a positive correlation with the sand-binder ratio, albeit with a minimal impact. Too low or high sand-binder ratio leads to a decrease in strain-hardening ability. Moreover, the as-prepared ECC exhibits a comparatively reduced tensile strain capacity when using locally produced unoiled PVA fiber as opposed to imported oiled PVA fiber. Finally, the environmental impact and economic benefits of the as-prepared low-cost ECC and Typical ECC are compared. The as-prepared low-cost ECC has good strain-hardening ability and low cost, indicating a potential application in real engineering.

The splitting tensile strength and impact resistance of concrete reinforced with hybrid BFRP minibars and micro fibers

Basalt fiber reinforced polymer (BFRP) minibar is a novel kind of macro fiber, which is high-performed, green and durable. This study aimed to use hybrid BFRP minibars and micro fibers to control cracks of concrete from micro size to macro size, ultimately improving the mechanical properties of concrete. The compressive strength, splitting tensile strength and impact resistance of concrete reinforced with hybrid BFRP minibars and various micro fibers were tested and evaluated. The micro fibers contained micro basalt fibers, polyvinyl alcohol (PVA) fibers and steel fibers. Test results showed that the hybrid fibers provided significantly positive synergistic effects on the impact resistance, compressive and splitting tensile strength of concrete. Micro fibers improved the microcrack resistance capacity of concrete that increased with micro fiber content and modulus, but most of fractured during the development process of microcracks owing to their tiny size, showing little contribution to macrocrack resistance. BFRP minibar showed the pull-out failure, and the force preventing BFRP minibar from pullout bridged macrocracks, improving the macrocrack resistance capacity of concrete., but they seldom improved the microcrack resistance capacity of concrete because of its large size. Hybrid fibers improve the sustained resistance to crack during the whole crack development process owing to the synergistic contribution of hybrid fibers. Thereby, the concrete reinforced with hybrid 1.5% BFRP minibars and 0.75% micro steel fibers showed the highest compressive strength, splitting tensile strength and final-fracturing impact life under the failure probability of 30%, which were 22% 29% and 415% higher than those of concrete with mono 1.5% BFRP minibars. The method, which is that using hybrid macro fibers and micro fibers with high modulus and proper content to reinforce concrete, supports for further improving the mechanical properties of concrete in practice.

High performance polyvinyl alcohol/lignin fibers with excellent mechanical and water resistance properties

To address the shortcoming of Polyvinyl alcohol (PVA) fibers for food or medical packaging materials including low mechanical strength and poor water resistance, lignin (LN) was used as raw material, acetone/H2O as solvent to self-assemble into lignin nanoparticles (LNP) by adverse solvent precipitation approach, and then PVA/LNP composite fibers with different LNP contents were fabricated successfully by wet and dry spinning. Herein, vast hydrophilic hydroxyl groups in PVA decreased owing to the hydrogen bond between LN and PVA, Especially, with only 0.5 wt% loading of LNP into the PVA/LNP fibers, the diameter was 94.4 dtex, tensile strength was 10.1 cN/dtex (1279.8 MPa), initial modulus was 94.7 cN/dtex (12.0 GPa), the crystallinity was 56.7 %, the orientation was 97.1 %, and water contact angle was 103.1°. Compared with pure PVA fibers, the tensile strength of PVA/LNP-0.5 fibers was increased by 44.2 % and the contact angle was increased 37°. This work provides novel insights into obtaining lignin-reinforced PVA composite fibers with strong mechanical properties and excellent water resistance properties, indicating the potential of the PVA/LNP fibers for food or medical packaging application.

Effects of textile type on the flexural properties of prefabricated hollow-core slabs strengthened with PVA fibers-improved TRM

In this study, the utilization of textile-reinforced mortar (TRM) in the strengthening and rehabilitation field is investigated. To regulate crack width, polyvinyl alcohol (PVA) fibers were incorporated into the TRM matrix. Nine prefabricated hollow-core slabs strengthened with TRM, along with one reference slab, were subjected to static loading using a 4-point bending apparatus. The experimental variables consisted of the type of textile (glass, basalt, and carbon) and the number of textile layers (one, two, and three layers). The experimental findings demonstrated that the inclusion of PVA fibers improved the TRM by effectively controlling crack width and increasing energy absorption capacity. Among the textile types, carbon TRM-strengthened slabs exhibited the highest flexural capacity. This capacity increased by 74%, 119%, and 132% for slabs strengthened with one, two, and three layers of textile, respectively. Glass TRM-strengthened slabs demonstrated superior deformability, with an increase rate ranging from 202% to 331%. Finally, to predict the flexural capacity and deflection of the tested slabs, a theoretical analysis was conducted and validated by comparing the theoretical predictions to the actual test results for accuracy and reliability.

Use of creep and recovery protocol to assess the printability of fibre-reinforced 3D printed white Portland cement composites

ABSTRACT White Portland cement is an ideal choice for producing 3D printed coloured composites due to its inherent whiteness. However, the uncontrollable rheological properties limit the establishment of printed structures and thus affect the mechanical properties. In this study, the polyvinyl alcohol (PVA) and polypropylene (PP) fibres were utilised as reinforcement materials in 3D printed white Portland cement composites (WPCCs) to improve the printability and toughness by controlling creep properties, aiming to build better printed structures. Experimental results show that the addition of PVA and PP fibres effectively improve the creep properties of WPCCs, and printed structures can be well built by controlling creep properties. Specifically, the thixotropy of WPCCs with PVA and PP fibre is improved within specific content ranges of 0∼1% and 0.4∼0.8%, respectively. Compared with reference sample, the flexural strength increases by approximately 148.8% and 90.2% when the PVA and PP fibre contents reach 1.25% and 1%, respectively.

Synergism of steel fibres and PVA fibres on the fracture and mechanical properties of ultra-high-performance concrete

The influence of the volume fraction (VF) of steel fibres, polyvinyl alcohol (PVA) fibres and their combination on the mechanical and fracture mechanical properties of ultra-high-performance concrete (UHPC) was studied. To analyse the synergistic effect of steel fibres and PVA fibres on the deformation properties of UHPC, the gain ratios (the ratios of the mechanical properties of UHPC reinforced with hybrid fibres (HUHPC) with those of UHPC reinforced with steel fibres (SUHPC)) were obtained for equal total fibre VFs and equal steel fibre VFs. The steel and PVA fibres reduced the compressive strength of the UHPC to some extent and, with increasing VF, the ratios of flexural strength/compressive strength and tensile strength/compressive strength increased gradually. The fracture mechanical properties of the UHPC were significantly improved with the addition of steel fibres and PVA fibres; the latter were superior in improving the deformation properties of the UHPC. Except for compressive strength, the gain ratios of mechanical parameters of HUHPC to SUHPC calculated with equal steel fibre VF were higher than for equal total fibre VF; 0.25% PVA fibres mixed with SUHPC further improved the bending tensile and fracture mechanical properties.

Effects of PVA fibers and multi-walled carbon nanotubes reinforcement on uniaxial compression fatigue properties of Engineered geopolymer composites

As a new type of green and environmentally friendly cementing material, engineered geopolymer composites (EGC) have broad application prospects. In this study, uniaxial compression fatigue tests were conducted to investigate the fatigue properties of geopolymer material. A total of 137 samples were tested to investigate the effects of carbon nanotubes content, polyvinyl alcohol (PVA) fibers volume content, and maximum stress level on the fatigue life and deformation of geopolymers. The results showed that the fatigue life of geopolymers obeys Weibull distribution, and PVA fibers and multi-walled carbon nanotubes (MWCNTs) achieved multiscale enhancement of the fatigue life by up to 16.34 times. The total strain accumulation, residual strain, and fatigue stiffness of the geopolymers under fatigue loading exhibited a three-stage evolution rule, with stability within the secondary creep branch. In the process of EGC production, the innovative adoption of optimized MWCNTs surface modification and dispersion strategies improved the uniformity of MWCNTs distribution in the matrix. Scanning electron microscopy (SEM) confirmed the hybridization of MWCNTs and PVA fibers at the microscopic level, which can achieve multi-scale enhancement of geopolymers. This study successfully optimized the content of MWCNTs and PVA fibers, further expanding the application range of composite materials.

Durability prediction of geopolymer mortar reinforced with nanoparticles and PVA fiber using particle swarm optimized BP neural network

Abstract In this study, polyvinyl alcohol (PVA) fibers and nanoparticles were incorporated to enhance the durability of geopolymer mortar (GM) with metakaolin (MK) and fly ash (FA). The dosage of nano-SiO2 (NS) was 0–2.5% and that of PVA fiber was 0–1.2%. The durability of GM includes resistance to chloride ion penetration, freeze–thaw cycles, and sulfate erosion. Compared with the single BP neural network (BPNN) model, a particle swarm optimized BPNN (PSO-BPNN) model was utilized to predict the resistance to chloride ion penetration, freeze–thaw cycles, and sulfate erosion of GMs with different dosages of nanoparticles and PVA fibers. In the model, the dosage of NS, PVA fiber, FA, and MK were used as input layers, and the durability parameters of electric flux, mass loss, and compressive strength loss of GMs were used as output layers. The result exhibits that the root mean square errors (RMSEs) of BPNN for resistance to chloride ion penetration, freeze–thaw cycles, and sulfate erosion of GM mixed with nanoparticles and PVA fibers are 145.39, 6.43, and 2.19, whereas RMSEs obtained from PSO-BPNN are 76.33, 2.87, and 1.03, respectively. The NN optimized by particle swarm algorithm has better prediction accuracy. The PSO-BPNN can be utilized for estimating durability of GM reinforced by NS and PVA fiber, which can provide a guide for the proportion design of GM with PVA fiber and NS as well as for the engineering practice in the future.

Upcycling use of red mud-based solid waste in engineered cementitious composites: Properties, activation mechanism, and life-cycle assessment

In this study, a low-carbon engineered cementitious composite (ECC) was produced by combining alkali-activated red mud (RM)/ground granulated blast-furnace slag (GGBS) with polyvinyl alcohol (PVA) fibers as the reinforcement. Both calcium aluminosilicate hydrate (C-A-S-H) and sodium aluminosilicate hydrate (N-A-S-H) gels are detected in the reaction products. A higher modulus of sodium silicate in the activator results in a higher degree of reaction of silicates in the samples, but not promising a higher mechanical property. The potential mechanism of iron activation in the alkali-activation RM-based ECC system was revealed. The four-point bending test results indicate a large deflection ability and multiple cracking characteristics of the composite. Life cycle assessment of this system is also presented by calculating energy consumption and carbon emissions. This study not only sheds light on the feasibility of using RM in the preparation of high-toughness alkali-activated ECC but also provides a promising method to upcycle industrial solid wastes in a highly effective way.

Optimum Design of Mixture Proportion and Microscopic Analysis of Cement-Stabilized Macadam by Rubber Powder and Fiber

Abstract Based on the orthogonal test method, the mixture proportion design of cement-stabilized macadam (CSM) modified with rubber powder and fiber is studied. With strength and dry-shrinkage as key indices, the influence of length of polyvinyl alcohol (PVA) fiber, fiber content, particle size of rubber powder, and rubber powder content on the performance of CSM is analyzed, and the optimum mixing proportion is determined. Based on this, the modification mechanism of CSM by rubber powder and fiber is further studied from a micro perspective. The results show that the 7-day unconfined compressive strength of CSM gradually increases with the increase of fiber length. With the increase of fiber content, the compressive strength shows a trend of first increasing and then decreasing. The 7-day unconfined compressive strength of CSM gradually increases with the increase of rubber powder mesh size and linearly decreases with the increase of rubber powder content. The 28-day average dry-shrinkage coefficient of CSM shows a trend of first decreasing and then increasing with the increase of fiber length and fiber content, and gradually increasing with the increase of rubber powder mesh number and rubber powder content. Considering the strength and shrinkage characteristics, the optimum mixing parameters are 40 mesh rubber powder, 0.5 % rubber powder, 18-mm fiber length, and 1.2-kg/m3 fiber content. Scanning electron microscopy results show that there is a gap between the rubber powder and the cement matrix, and the interface between the two is discontinuous, with weak bonding, resulting in a decrease in the compressive strength of CSM. PVA fiber can improve the toughness of CSM. It has good adhesion with cement matrix. It forms a three-dimensional network support structure in the CSM mixture and can restrain water loss in the cement matrix, thus greatly improving the cracking resistance of CSM.

Study on the durability of polyvinyl alcohol fiber reinforced concrete constructed by mixing - casting and mixing - spraying technology in seawater

Polyme fiber-reinforced concrete, with many superior features has solved some limitations of regular concrete. However, polyme fiber reinforced concrete to ensures long-term durability in sea water environments, it is necessary to combine many factors such as quality requirements material, durability and production technology of concrete,... This paper presents the experimetal results on the influence of durability (flexural strength, compressive strength) of polyme fiber (used polyvinyl alcohol fiber – PVA) reinforced concrete using mixing - casting and mixing - spraying technology in sea water environment. The experimental results show that PVA fiber reinforced concrete has the same strength development as normal concrete in both normal water and seawater. The strength of PVA fiber reinforced concrete cured in seawater environment at long-term ages (90 and 180 days) lower than that cured in normal water is 4.5%.

On the Hydrogen Peroxide Sensing employing Fibres composed of Polyvinyl alcohol (PVA) and Polyaniline (PANI)

The sensitivity of an electrocatalyst depends upon the kinetics of electrochemical reactions occurring at its surface. In this work, we prepared the polyvinyl alcohol (PVA) and polyaniline (PANI) nanofibres using a facile and cost-effective electrospinning method. We observed that the fibres composed of PANI and PVA exhibited efficient sensing of hydrogen peroxide (H2O2) as compared to the fibres prepared employing PVA alone. At low concentration of H2O2, a two-fold enhancement in the sensing activity is noticed in case of the fibre prepared using PVA-PANI (as compared to PVA fibres). On the other hand, at higher concentration, the sensitivity is around five times high. The enhancement in the sensing activity for PVA-PANI nanofibres is due to the increase in conductivity and electrochemical surface area upon addition of conducting PANI. The increased conductivity enhances the surface energy of the fibre and increased electrochemical surface area enhances the number of reactive sites, which results in enhanced sensing activity. The above analysis is further supported via the impedance analysis showing lower charge transfer resistance for PVA-PANI sample.

Multiscale analysis of recycled coarse aggregate concrete under the synergistic action of KH560 and PVA fibers

Considering the long-term working performance of the waste concrete building elements, this study used 3-Glycidoxypropyltrimethoxysilane (KH560) and Polyvinyl alcohol (PVA) fibers to modify the recycled concrete (RC) with the aim of improving the mechanical and long-term properties of RC. In this study, the mechanical properties of recycled coarse aggregate (RCA) concrete before and after modification were systematically investigated. The macroscale results showed that KH560 compensates for the reduced compressive strength of RCA concrete due to PVA fibers. The synergistic effect of PVA and KH560 substantially increased the flexural and shear strength of RCA concrete, with a maximum increase of 22.6% in flexural strength when the RCA substitution rate was 80%. The results of three microscopic tests (SEM / FTIR/XRD) revealed that KH560 increased the content of cement gel, which then optimized the internal pore structure of RCA concrete. The chemical reaction between KH560 and cement produced SiKH560-OKH560-SiCSH. At the nano-scale, computational analysis methods in atomistic modeling techniques were employed to model PVA fibers, cement and KH560, and the dynamic and static simulation results of the model were combined to discover a consistent SiKH560-OKH560-SiCSH chemical bond between KH560/CSH and both old and new CSH, Additionally, the findings revealed the coexistence hydrogen and ionic bonds. KH560 improves the interaction between PVA fibers and cement by forming numerous hydrogen bonds, and resolves the weak interface between the new and old cement through stable chemical bonds.

Effect of PVA fiber on properties of geopolymer composites: A comprehensive review

Geopolymer composites (GC) have drawn much attention regarding sustainable cementitious materials in recent years. Polyvinyl alcohol (PVA) fiber is often added into GC to improve properties of the composite. In order to better understand the effect of PVA fiber on properties of GC and its mechanism, this paper sums up the advance in properties of PVA fiber-reinforced geopolymer composites (PVA-FRGC). Viscosity of GC increases with the increase of PVA fiber, so a reduced setting time and poor flowability of GC occurs. This paper expounds that PVA fiber with moderately high content and short length has significant effects on mechanical properties of GC. Most mechanical performances of GC can be tremendously improved thanks to fiber-bridge effect. Besides, it's worth noting that 0.2%–0.3% content of PVA fiber has optimal enhancement in compressive strength of GC. The details also contain the enhancement of PVA fiber incorporation on durability of GC, and related models used in predicting performance of PVA-FRGC are expounded. In addition, the strengthening mechanism from scanning electron microscope (SEM) images showed that PVA fibers had strong chemical bond strength and friction bond strength with geopolymer matrix, and future work need to be done is recommended. In general, PVA-FRGC has an excellent performance on mechanical properties and durability compared with plain GC. The paper is designed to make contributions for development of green building materials. This paper aims to provide guidance for the application of PVA fiber in GC and serve as support for practical application of PVA-FRGC in construction engineering.