Incorporated Poly Vinyl Alcohol Research Articles

Efficient removal of polycyclic aromatic hydrocarbons from aqueous solutions using green cyclodextrin-maltodextrin nanosponge incorporated polyvinyl alcohol cryogel

Developing efficient adsorbents for removing polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions is a significant and worthwhile approach. In this study, we showcase a method for fabricating β-cyclodextrin-maltodextrin nanosponges (βCD-MD) incorporated polyvinyl alcohol (PVA) cryogel for removing PAHs from aqueous solutions. The composite nanosponges enhanced the adsorption efficiency of PAHs such as Naphthalene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, and Benzo[a]pyrene from water samples and the porous PVA cryogel helped to entrap and prevent the loss of the adsorbent. This efficacy was attributed to the strong affinities of PAHs toward βCD-MD nanosponges, facilitated by hydrophobic interactions between the analytes and the hydrophobic inner region present in both dextrins. The removal efficiency of the prepared βCD-MD/PVA composite cryogel was more than 95 % for all 8 PAHs (C0 = 5.0 mg/L) in less than 30 min, and the experimental data were well described by the Freundlich isotherm and the pseudo-second-order kinetic model. Additionally, the βCD-MD/PVA composite cryogel exhibited a maximum adsorption capacity ranging from 16.34 to 18.49 mg/g for eight PAHs. Moreover, the thermodynamic study revealed that the adsorption of PAHs was an endothermic and spontaneous process. The βCD-MD/PVA composite cryogel exhibited an abundance of polar functional groups along with numerous hydrophobic cavities and regions. It demonstrated high mechanical and thermal stability and maintained high removal efficiency even after seven adsorption–desorption cycles. Overall, it was concluded that βCD-MD/PVA composite cryogel can be utilized as a high-performance, eco-friendly, and sustainable alternative for PAH removal.

Synthesis and characterization of porous silica and composite films for enhanced CO₂ adsorption: A circular economy approach

This study explores the synthesis and application of carbon-negative technology that leverage circular economy and environmentally friendly methodologies. Porous silica using plant-derived silica sources and self-assembled lignin templates were prepared, achieving an impresive surface area of up to 104.76 m2/g. Additionally, we prepared porous composite films via a freeze-drying process incorporating polyvinyl alcohol (PVA). These films demonstrated enhanced tensile properties, with a tensile strength reaching 285.72 kPa. Notably, the film surfaces engaged in a third-body tribology mechanism, which endowed them with excellent abrasion resistance and a low friction coefficient. The specific surface area of the films was measured at 20.15 m2/g, making them ideal substrates for CO₂ adsorption functionalization. The functionalized films showcased outstanding CO₂ adsorption capabilities, with a maximum uptake of 29.38 mg/g. Furthermore, they retained over 90% of their adsorption capacity after five adsorption/desorption cycles. Under high CO₂ conditions, these composite films combine the desirable attributes of both solid and liquid adsorbents—high surface area, low volatility, and adsorption stability—contributing significantly to greenhouse gas mitigation and the pursuit of carbon neutrality.

Physical, mechanical characterization, and artificial neural network modeling of biodegradable composite scaffold for biomedical applications

The performance of substitute osteoconductive scaffolds in guiding new bone formation and creating vital biological conditions in living organisms is of crucial importance. In this study, bioresorbable scaffolds were synthesized by incorporating polyvinyl alcohol (PVA) with hydroxyapatite nanoparticles (n-HAP) and Iron oxide (Fe3O4) nanoparticles (NPs) (MNPs) using a freeze-drying technique. Subsequently, the magnetic nanocomposite scaffolds were immersed in a phosphate-buffered saline (PBS) solution for 24 days to assess their degradability percentage. The physicochemical and morphological properties of the magnetic nanocomposite scaffolds were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Furthermore, the mechanical behavior was examined, while the pore dimensions and porosity were determined using immersion-based techniques. Noteworthy attributes of the magnetic nanocomposite scaffolds were observed, including a maximum swelling capacity of 176 %, a substantial porosity of 72.7%, and impressive mechanical characteristics, such as a compressive strength of 4.61 MPa and an elastic modulus of 2.13 GPa. The degradation study conducted in a PBS solution revealed that the scaffold with the highest n-HAP content (20 wt%) exhibited a degradation rate of approximately 21% after a 24-day period. The influence of environmental conditions, including time, temperature, and salt-containing environments, on the swelling behavior and bio-resorption of the scaffolds was examined. Additionally, an artificial neural network (ANN) was developed to forecast the impact of weight percentages of n-HAP and MNPs on various scaffold properties. According to the ANN predictions, increasing the weight percentages of n-HAP and MNPs resulted in a reduction in pore size, an increase in porosity, and an improvement in the mechanical properties of the scaffolds. Moreover, the incorporation of a higher number of nanoparticles led to increased absorption and swelling, facilitating bone tissue formation. Satisfactory accuracy in predicting scaffold properties was demonstrated through error analysis and linear regression plots, aiding designers in selecting appropriate weight percentages of nanoparticles for future designs. The findings indicate that the synthesized magnetic nanocomposite scaffold closely resembles the physical and mechanical characteristics of natural bone tissue. The utilization of an ANN for performance assessment demonstrated favorable efficiency and effectiveness. Therefore, the significance of the current study lies in the comprehensive investigation of the synthesis and characterization of a biodegradable magnetic nanocomposite scaffold, as well as the utilization of an ANN-based approach to predict and optimize its properties for potential bone tissue engineering applications.

Optimizing toughness and cost-effectiveness in one-part geopolymers via fiber reinforcement: A comprehensive investigation of PVA, PE, and glass fibers

This study explores developing and characterizing a one-part geopolymer, an innovative and sustainable construction material. The effects of incorporating polyvinyl alcohol (PVA), polyethylene (PE), and glass fibers (GF) on the toughness of slag and fly ash-based one-part geopolymer mortars were investigated through compressive, three-point flexural, and four-point bending tests. The findings demonstrate that fiber incorporation reduces fluidity and compressive strength due to increased porosity, lower elastic modulus of fibers, and weak interfacial bonding. However, fibers significantly enhance damage resistance and toughness via crack bridging and load transfer mechanisms. Formulations with 2 % PVA fibers and combinations of 1 % PVA with 1 % PE fibers and 1 % PVA mixed with 0.5 % PE and 0.5 % GF demonstrate excellent toughness. Notably, the latter two fiber blends achieve 14 % and 10 % cost reductions, respectively, compared to using only PVA fibers, making them economically viable for large-scale applications. Scanning electron microscopy and X-ray diffraction provided insights into the toughening mechanisms, including crack bridging, fiber pull-out, and enhanced stress distribution within the geopolymer matrix. Digital image correlation techniques further elucidated the fibers' role in improving the post-cracking behavior and structural resilience under load.

Robust construction of polyvinyl alcohol intercalated graphene oxide nanofiltration membrane for desalination via pervaporation

The construction and modification of a Graphene Oxide (GO) membrane, incorporating polyvinyl alcohol (PVA) cross-linked with maleic acid (MA) and supported by a nylon membrane, have been successfully completed. Systematic variations in PVA and MA concentrations were conducted to achieve membranes with favorable characteristics, stability, and excellent desalination performance. Optimization studies utilizing the Central Composite Design (CCD) revealed that the most optimal desalination results were obtained with 10 mL of PVA (0.1 mg mL−1) and 0.9 M of MA (GO-MA0.9-PVA10/Nylon membrane). Experimental findings demonstrated that the inclusion of PVA and MA resulted in an increased interlayer distance of GO and enhanced membrane stability. The addition of PVA increases GO membrane hydrophilicity, while the addition of MA reduces membrane hydrophilicity. The GO-MA0.9-PVA10/Nylon membrane exhibited the highest desalination performance, boasting a rejection value exceeding >99.9% and a permeance of 18.76 kg m−2.h−1 under 1% NaCl feed at a temperature of 50 °C. This membrane demonstrated consistent desalination performance stability over an extended period of up to 70 h. Moreover, it exhibited durability through 8 cycles of 24-h usage with washing treatment. In conclusion, the GO-MA0.9-PVA10/Nylon membrane is strongly recommended for practical applications, outperforming other membrane options based on the comprehensive evaluation of its stability and desalination efficiency.

Study on Motion Sensing Using Textile Electrodes-Focusing on the Application of PANI Conductive Material

Abstract This study investigates the application of textile electrodes using PANI (Polyaniline) conductive material for motion sensing, specifically aimed at motion monitoring for the elderly. By depositing a PANI conductive layer on the base of warp-knitted fabric through in-situ polymerization and plasma treatment, a PCCWKF (Polyaniline Coated Conductive Warp-Knitted Fabric) with enhanced electrical conductivity and mechanical flexibility was developed. The research optimized the electrical resistivity and durability of PCCWKF by incorporating Polyvinyl Alcohol (PVA) as a toughening agent, improving the adhesion of the PANI conductive layer to the textile substrate. The sensor’s efficacy in accurately recording and monitoring motion amplitude and frequency in real-time was demonstrated through its application in smart clothing, focusing on respiratory, elbow, and knee motion monitoring. This study holds significant implications for the advancement of wearable technology and smart textiles in the health monitoring of the elderly.

Structural, thermal and optoelectrical study of PVA/iron oxide nanocomposite films

AbstractThe work reported here deals with fabricating iron oxide nanoparticles incorporated polyvinyl alcohol nanocomposite films via the solution‐casting green route, characterized using various characterization techniques. X‐ray diffraction analysis shows interaction of nanoparticles with the polyvinyl alcohol matrix, scanning electron microscopy shows surface morphology of crack‐free films, energy dispersive spectroscopy indicates elemental purity, tensiometer analysis shows changing behavior of hydrophilic to hydrophobic, thermogravimetric analysis shows improved thermal stability, ultraviolet‐visible spectroscopy shows tunable optical properties, and frequency response analysis shows improved electrical properties. A small incorporation (1 wt. %) of iron oxide nanoparticles has induced significant alternations in structural, wetting, thermal, optical, and electrical properties of the polyvinyl alcohol‐based nanocomposite films. Results showed notable changes in the structural phases, water contact angle (39.5° to 97.7°), optical absorption edge (5.12 eV to 4.84 eV), indirect band gap (4.99 eV to 4.68 eV), direct bandgap (5.41 eV to 5.21 eV), and band tail (0.57 eV to 0.89 eV) from native polyvinyl alcohol to polyvinyl alcohol/iron oxide nanocomposite films. Enhancements were observed in refractive indices, optical conductivity, optical dielectric loss, thermal stability, dielectric constant, and dielectric loss on incorporating iron oxide nanoparticles into the polyvinyl alcohol matrix. The fabricated nanocomposite films might be a potential material for optoelectronic and microelectronics applications.

Red-Mud, A Golden Waste for Radiation Shielding”: Red-Mud Polymer Composites for High-Performance Radiation-Shielding Components

Red mud (RM) is generated in huge quantities and holds the ability to form radiation shielding structures due to its metal oxide-rich composition. In this work, this metal oxide-rich waste is converted into X-ray shielding sheets via a solution-casting technique incorporating polyvinyl alcohol (PVA) as a binder which holds RM particles together. We show a successful fabrication of sheets employing varying wt.% of RM (60, 70, 80, and 90 wt.%). The linear attenuation coefficient (LAC) values have been compared to analyze what maximum RM wt.% can effectively shield diagnostic X-rays at energies of 60 kVp, 90 kVp, and 120 kVp. Structural characterizations of the fabricated samples have been examined through SEM, XRD, RAMAN, and FTIR. The LAC analysis revealed that 70 wt.% of RM with PVA binder yields highest radiation shielding. However, with increased wt.% of RM there is a catastrophic decrease in strength and shielding capability of the composite due to the formation of voids due to decreased wt.% of polymer binder. So, an innovative polymer-rich coating has been applied to RM composite having 90 wt.% of RM, which boosted the LAC and strength, but not more than RM composite having 70 or 80 wt.% of RM. The UV shielding analysis of best samples having 70 and 80 wt.% of RM was also analyzed to show the capability of RM in shielding UV along with X-ray.

Development and Characterization of Electrospun Piper Betle - Azadirachta indica Leaf Extract Incorporated Polyvinyl Alcohol Nanofibrous Composite Mats

Development and Characterization of Electrospun Piper Betle - Azadirachta indica Leaf Extract Incorporated Polyvinyl Alcohol Nanofibrous Composite Mats

Synthesis of sulfonated graphene oxide loaded polyvinyl alcohol membranes for esterification of ethyl propionate in a pervaporative catalytic membrane reactor system: Experimental and modelling

Ethyl propionate was produced using pervaporative catalytic membrane reactor-separator (PCMR) system. The reaction and separation were carried out by sulfonated graphene oxide (SGO) incorporated polyvinyl alcohol (PVA) membranes. The catalyst was prepared by sulfonation of graphene oxide using chlorosulfonic acid to achieve the desired degree of sulphonation. The catalyst and membranes were characterized by various techniques like Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Energy dispersive fluorescence spectroscopy (EDXRF), etc. Various parameters including catalyst loading, reaction time, reaction temperature, molar ratio, downstream pressure, etc. were studied. The PVA membrane crosslinked with fumaric acid was synthesized with different SGO catalyst loading. The prepared membrane was used to perform esterification of ethyl propionate in batch mode with PCMR system. Modelling and simulation studies were carried out to compare the experimental and predicted results. The heterogeneous Eley-Rideal kinetic model was fitted to obtain the conversion values with time and compared with the experimental results. Compared to the batch reactor the conversion was 17–41 % more in PCMR for different molar ratios and temperatures. The water flux was varied from 1.92 to 8.8 mol /m2h with time. Maximum conversion (98 %) occurred at higher temperatures, about 90 % conversion was achieved in the study at 60 ℃ in 8.5 h. The highest selectivity of water was obtained as 145 at a pressure of 6 mmHg with the hydrophilic PVA membrane.

Simple Thermal Annealing‐Assisted Direct Synthesis and Optical Property Study of CuO Nanoparticles Incorporated Polyvinyl Alcohol Films

This article reports a simple thermal annealing‐assisted direct synthesis method to prepare copper oxide (CuO) nanoparticles incorporated in polyvinyl alcohol (PVA) films and a systematic study of their optical properties. CuO‐PVA nanocomposite films are prepared with a different weight percentage of CuO in the PVA matrix. Scanning electron microscopy (SEM), X‐ray diffraction (XRD), UV‐visible spectroscopy, and photoluminescence spectroscopy are employed to study the prepared films. XRD confirms the formation of crystalline CuO nanoparticles in PVA, while the SEM analysis shows uniformly distributed spherical nanoparticles in PVA. The findings show that thermal annealing at a mild temperature plays a crucial role in improving the crystallinity and optical properties of the nanocomposite film. In comparison to PVA, CuO‐PVA nanocomposite exhibits improved absorption with a new absorption band in the lower wavelength region. The nanocomposite samples excited with 300 nm show intense photoluminescence (PL) at 365 nm and an increase of PL intensity with CuO concentration in the PVA matrix. In contrast, samples excited with 425 nm show green emission at 550 nm in the visible region of the electromagnetic spectrum. The PL in CuO‐PVA nanocomposites can be originated due to the transitions associated with acceptor and donor defects in the material. The study opens up a new route to fabricate CuO‐PVA nanocomposites with superior optical properties.

Graphene fortified polyvinyl alcohol based nanofibre membranes for preserving perishable food

In recent years, graphene as a biomaterial has received considerable attention due to its outstanding physio-mechanical properties. In the present work, we found superior tensile strength, hydrophobic and antibacterial activities in graphene incorporated polyvinyl alcohol (PVA) based nanofibers, prepared by electrospinning. A series of ultrafine graphene-based ink (G-Ink) incorporated PVA nanofiber (GPN) with different concentrations of graphene (0, 0.008, 0.02, 0.04, 0.06, and 0.08% w/v) was fabricated. To overcome difficulty in direct dispersing graphene into the PVA solution, we have prepared graphene-based ink for dispersing into polymer solution. The morphology, composition, mechanical behaviour, and surface wettability of these membranes was investigated. The Fourier transform infrared spectra and the Raman spectra confirmed the successful incorporation of graphene into the GPN. Graphene when used as a nanofiller in polymers, provides excellent mechanical properties (814%), hydrophobicity (40%), and antibacterial properties. In the current study we tested GPN membranes for preserving two fast rotting foods like coriander leaves and tomato. We found that GPN membrane can be used safely for food packaging applications to increase the shelf life of perishing food items, such as up to 3 days for coriander leaves and 8 days for tomatoes.

Fabrication and in vitro evaluation of polyvinyl alcohol/bio-glass composite for potential wound healing applications

In this study, a novel composite is fabricated by incorporating Polyvinyl alcohol (PVA) and Bio-Glass (BG) via the freeze-thaw method. PVA pre-polymer is prepared in three different concentrations i.e. (2%, 5%, and 10%) by dissolving PVA powder in distilled water by using a hot plate magnetic stirrer at 80° C, and a constant concentration of BG i.e 2% is added into each PVA prepolymer. Total six specimens including (PVA (2%), PVA (5%), PVA (10%), PVA (2%)/BG (2%), PVA (5%)/BG (2%), and PVA (10%)/ BG (2%) were prepared in which pure PVA specimens acts as a control group. The physicochemical and mechanical properties of the specimens were examined. Various characterization tests such as scanning electron microscopy (SEM), swelling analysis, degradability analysis, hygroscopicity, pH sensitivity, tensile analysis, gel fraction test, water vapor transmission rate (WVTR), and, contact angle analysis were performed on the samples. SEM analysis showed that with the increase in PVA concentration, the material becomes smoother and more compact. Results from the current study showed that tensile strength, degradation rate, and get content are directly proportional to PVA concentration, while swelling capacity, pH sensitivity, hygroscopicity, WVTR, and hydrophilicity are inversely related to PVA concentration. Moreover, with the addition of BG, tensile strength, degradation rate, pH sensitivity, swelling capability, hydrophilicity, and, gel content of the specimens is increased, whereas, WVTR is decreased and, hygroscopicity remains unchanged. Furthermore, results from this study must be taken a step ahead & biocompatibility must be tested to evaluate the biological performance.

Chitosan-gelatin hydrogel incorporating polyvinyl alcohol and MnFe double-layered hydroxide nanocomposites with biological activity

In this research, a novel nanocomposite scaffold was developed based on a natural chitosan-gelatin (CS-Ge) hydrogel by incorporating synthetic polyvinyl alcohol (PVA) and MnFe layered double hydroxides (LDHs). The CS-Ge/PVP/MnFe LDH nanocomposite hydrogels was characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-Ray (EDX), vibrating-sample magnetometer (VSM), and Thermal gravimetric analysis (TGA). The biological tests conducted showed cell viability of the healthy cell line exceeding 95 % after 48 and 72 h. Additionally, the nanocomposite demonstrated high antibacterial activity against P. aeruginosa bacteria biofilm, as confirmed through Anti-biofilm assays. Furthermore, mechanical tests revealed that the storage modulus was greater than the loss modulus (G'/G" > 1), confirming the appropriate elastic state of the nanocomposite.

Synthesis of ultra-thin graphene oxide/ reduced graphene oxide nanocomposites and examine their properties

Graphene oxide and reduced graphene oxide become center of attraction of researchers for last two decades due to its structural and morphological properties which contribute a unique ability to it. By the incorporation of graphene oxide (GO) or reduced graphene oxide (r-GO) into the polymer matrix makes extraordinary change in its general properties to extraordinary properties. The production of GO and r-GO in large scale with cost effecting way is still become challenge. This present work describes the preparation and characterization of GO incorporated Poly vinyl alcohol (PVA) nanocomposite and r-GO incorporated PVA nanocomposite. By following the modified Hummers reaction technique GO and r-GO. Which is cost effective and easier way GO and r-GO of production. The structural properties of GO and r-GO were examined via UV–vis, FTIR, XRD and SEM. The spectral outcomes of FTIR analysis showed the presence of functional groups in GO and r-GO. The comparative study of GO/r-GO of UV spectra is suggesting for π-π* transition on different wavelength. Various SEM images implied for the formation of ultrathin and homogeneously dispersed PVA supported graphene oxide and reduced graphene oxide nanocomposites. The r-GO is obtained by thermal reduction of GO causing a significant decrease in the amount of oxygen containing groups by which r-GO leads the higher specific surface area with less interlayer separation compared to GO.

Effect of anthocyanin-natural deep eutectic solvent (lactic acid/fructose) on mechanical, thermal, barrier, and pH-sensitive properties of polyvinyl alcohol based edible films

The aim of the current research was to fabricate and characterize the anthocyanin- natural deep eutectic solvent (NADES) incorporated polyvinyl alcohol (PVOH) based edible pH-sensitive films. Further the effectiveness of anthocyanin-NADES on the functional, structural, mechanical, and barrier properties of PVOH films has been investigated. The interaction and diffraction pattern at 19.1° for PVOH and NADES has been confirmed from FT-IR and XRD spectroscopy. The EDX spectra indicate the absence of metal components confirming the safety of the films. Additionally, the incorporation of NADES reduces the glass transition temperature and young modulus of PVOH films, whereas water vapour permeability (WVP), elasticity, and water solubility has been increased. The optical properties confirm that films provide reduced transparency confirming the usability against light-sensitive food products. The morphology in presence of NADES provides irregular flecks structures. A significant change in film color was observed on applying various pH buffers indicating the pH-sensitive property. Based on the above discussion, NADES aided PVOH-based edible films are considered as a potential candidate to be used as edible pH indicators for evaluating food quality during storage life, where the specific indicator can be ingested along with food products.

Synthesis and characterization of AlCl3-chitosan composite aerogels incorporating polyvinyl alcohol and bentonite clay

Synthesis and characterization of AlCl3-chitosan composite aerogels incorporating polyvinyl alcohol and bentonite clay

Promoted osteogenic differentiation of human induced pluripotent stem cells using composited polycaprolactone/polyvinyl alcohol/carbopol nanofibrous scaffold

Scaffold as a major part of tissue engineering plays an important role in the repairing process of the bone lesions. The scaffold's hydrophilicity plays a fundamental role in the initial cell attachment, and their growth, proliferation and differentiation processes. The aim of this study was to investigate the impact of hydrophilicity increasing in the hydrophobic scaffolds while combined with hydrophilic polymers on the osteogenic differentiation of induced pluripotent stem cells (iPSCs). In the present study, hydrophilicity of Polycaprolactone (PCL) electrospun nanofibers was improved using incorporating polyvinyl alcohol (PVA) and Carbopol (CP). Water uptake assay was confirmed that the hydration value of the PCL/PVA/CP was significantly increased in comparison with PCL and PCL/PVA nanofibers. In addition, the viability of the iPSCs grown on the PCL/PVA/CP was also significantly increased in comparison with the other two groups. Osteogenic differentiation evaluation demonstrated that the highest ALP activity and total calcium was detected in the iPSCs grown on the PCL/PVA/CP compared to the cells cultured on the PCL/PVA nanofibers. Although these values in the iPSCs cultured on the PCL/PVA was also significantly higher than those cells cultured on the PCL as a control group. Bone-related gene expression was also examined in the iPSCs cultured on the fabricated scaffolds. The results revealed that the highest expression level of genes was detected in the cells grown on the PCL/PVA/CP nanofibers. Taken together, these results indicated that the PCL/PVA/CP nanofibrous scaffold has greater osteoinductive potential than PCL/PVA and PCL nanofibers and could be considered as a potential construct in bone tissue engineering applications.

Characterization of PVA Fiber-Reinforced Pervious Concrete with Blended Recycled Ceramic Aggregates and Natural Aggregate

Effective industrial waste management is one of the important challenges facing modern society. Ceramic wastes occupy an important proportion of industrial waste. The utilization of waste of ceramics is becoming more and more attractive for many researchers to alleviate the environmental impact of industrial waste. As a low-impact development method, pervious concrete (PC) received more and more attention from researchers in recent years. However, the relatively low strength compared with ordinary concrete restricts the application of pervious concrete. This research used recycled ceramic coarse aggregates (RCCA) to partially replace natural coarse aggregates (NCA) to prepare recycled ceramic coarse aggregate pervious concrete (RCCAPC) and fiber-reinforced RCCAPC incorporating polyvinyl alcohol (PVA) fibers, and the effect of the replacement rate of RCCA and the amount of PVA fiber on the mechanical properties and permeability was investigated. The results show that RCCA can improve the mechanical properties of PC at a low substitution rate, as well as PVA fiber, and when the PVA content is about 0.3%, the enhancement effect is the best. Both RCCA replacement rate and PVA fiber content have little effect on the permeability coefficient of PC. Based on described studies, using RCCA to partially replace NCA at a low substitution rate is suitable for the preparation of PC, and PVA fibers can enhance the strength of PC, which may help to broaden the application scenarios of PC.

Properties and modification of sustainable foam concrete including eco-friendly recycled powder from concrete waste

Reusing recycled powder (RP) including recycled concrete powder (RCP) and recycled mortar powder (RMP) as an eco-friendly alternative binder benefits the reclamation of construction waste and reduces the cement demand. Considering that foam concrete (FC) which contains high-volume cement and supplementary cementitious material (SCM) has been largely used in building engineering owing to its low density and good thermal insulation performance, and thus, substituting RP for partial cement in preparing FC is more sustainable. This work studied the influence of RP type and replacement on the performance of newly-made FC, and some feasible modification methods for improving the performance of RP blended in FC were further provided. A series of micro and macro tests were conducted. The results show that the utilization of RP has no distinct impact on the dry apparent density, thermal conductivity and porosity of its prepared FC. When the RP replacement rate is below 15%, the compressive strength of FC containing RP is slightly lower than that of FC without RP, while the compressive strength of FC decreases significantly as high-volume RP incorporates. Incorporating polyvinyl alcohol (PVA) fiber decreases the drying shrinking of FC containing RP, and the RP-prepared FC incorporating 0.3% PVA fiber has lower drying shrinkage and higher strength than that without fiber incorporation. The addition of metakaolin (MK) improves the mechanical strength of RP blended in FC, and the compressive strength increases by 32.9–34.9% as 10% MK incorporates.