Polymers

Research

29 pages, 8447 KiB

Open AccessArticle

Preparation and Properties of Composite Graphene/Carbon Fiber Pouring Conductive Asphalt Concrete

by Zhenxia Li, Tengteng Guo, Yuanzhao Chen, Yibin Wang, Xiangjie Niu, Deqing Tang, Menghui Hao, Xu Zhao and Jinyuan Liu

Polymers 2023, 15(8), 1864; https://doi.org/10.3390/polym15081864 - 13 Apr 2023

Cited by 3 | Viewed by 1582

Abstract

To solve the problem of snow on steel bridge areas endangering traffic safety and low road traffic efficiency in winter, conductive gussasphait concrete (CGA) was prepared by mixing conductive phase materials (graphene and carbon fiber) into Gussasphalt (GA). First, through high-temperature rutting test, [...] Read more.

To solve the problem of snow on steel bridge areas endangering traffic safety and low road traffic efficiency in winter, conductive gussasphait concrete (CGA) was prepared by mixing conductive phase materials (graphene and carbon fiber) into Gussasphalt (GA). First, through high-temperature rutting test, low-temperature bending test, immersion Marshall test, freeze–thaw splitting test and fatigue test, the high-temperature stability, low-temperature crack resistance, water stability and fatigue performance of CGA with different conductive phase materials were systematically studied. Second, the influence of different content of conductive phase materials on the conductivity of CGA was studied through the electrical resistance test, and the microstructure characteristics were analyzed via SEM. Finally, the electrothermal properties of CGA with different conductive phase materials were studied via heating test and simulated ice-snow melting test. The results showed that the addition of graphene/carbon fiber can significantly improve the high-temperature stability, low-temperature crack resistance, water stability and fatigue performance of CGA. The contact resistance between electrode and specimen can be effectively reduced when the graphite distribution is 600 g/m². The resistivity of 0.3% carbon fiber + 0.5% graphene rutting plate specimen can reach 4.70 Ω·m. Graphene and carbon fiber in asphalt mortar construct a complete conductive network. The heating efficiency of 0.3% carbon fiber + 0.5% graphene rutting plate specimen is 71.4%, and the ice-snow melting efficiency is 28.73%, demonstrating good electrothermal performance and ice-snow melting effect. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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16 pages, 4771 KiB

Open AccessArticle

Entrapment of Acridine Orange in Metakaolin-Based Geopolymer: A Feasibility Study

by Antonio D’Angelo, Luigi Vertuccio, Cristina Leonelli, Mohammad I. M. Alzeer and Michelina Catauro

Polymers 2023, 15(3), 675; https://doi.org/10.3390/polym15030675 - 28 Jan 2023

Cited by 2 | Viewed by 1600

Abstract

Few studies have explored the immobilization of organic macromolecules within the geopolymer matrix, and some have found their chemical instability in the highly alkaline geopolymerization media. The present work reports on the feasibility of encapsulating the potentially toxic acridine orange (AO) dye in [...] Read more.

Few studies have explored the immobilization of organic macromolecules within the geopolymer matrix, and some have found their chemical instability in the highly alkaline geopolymerization media. The present work reports on the feasibility of encapsulating the potentially toxic acridine orange (AO) dye in a metakaolin based geopolymer while maintaining its structural integrity. The proper structural, chemical, and mechanical stabilities of the final products were ascertained using Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric (TGA/DTG), and mechanical analyses, whereas the dye integrity and its stability inside the geopolymer were investigated by the UV-Vis analysis. In addition, the antimicrobial activity was investigated. The FT-IR and XRD analyses confirmed the geopolymerization occurrence, whereas the TGA/DTG and mechanical (compressive and flexural) strength revealed that the addition of 0.31% (AO mg/ sodium silicate L) of AO to the fresh paste did not affect the thermal stability and the mechanical properties (above 6 MPa in flexural strength and above 20 MPa for compressive strength) of the hardened product. UV-Vis spectroscopy revealed that the dye did not undergo chemical degradation nor was it released from the geopolymer matrix. The results reported herein provide a useful approach for the safe removal of toxic macromolecules by means of encapsulation within the geopolymer matrix. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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24 pages, 10130 KiB

Open AccessArticle

Static and Dynamic Properties Study on Interface between New Polymer Materials and Silty Clay Based on Ring Shear Tests

by Jia Li, Jie Li, Jingwei Zhang and Guangzong Liu

Polymers 2023, 15(3), 634; https://doi.org/10.3390/polym15030634 - 26 Jan 2023

Cited by 1 | Viewed by 1384

Abstract

The polymer anti-seepage wall composed of polymer materials is a new technology for impermeable reinforcement in dykes and dams. Compared with traditional grouting materials, polymer grouting materials have the advantages of early strength, convenience, good anti-seepage performance, safety and durability. Because of the [...] Read more.

The polymer anti-seepage wall composed of polymer materials is a new technology for impermeable reinforcement in dykes and dams. Compared with traditional grouting materials, polymer grouting materials have the advantages of early strength, convenience, good anti-seepage performance, safety and durability. Because of the particularity of polymer materials, they form a “root-like” cementing status with dam soils after grouting. This complex interface affects the interaction between the wall and the dam, which subsequently influences the whole structure’s properties under loads. In this paper, based on an original designed test mould, an SRS-150 dynamic ring shear instrument was used to conduct static and dynamic ring shear tests to explore the static and dynamic properties of the polymer–silty clay interface. Moreover, influence laws and the related mechanism of different factors on the polymer–silty clay interface were studied in this paper. At the same time, the hyperbolic constitutive model of the polymer–silty clay interface was established, and the validity of the model was verified by comparing the numerical simulation with the relevant experimental results. The achievements of this paper are helpful as they provide a scientific basis for the structure’s mechanical analysis and lay the foundation for the promotion and application of the new anti-seepage technology. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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27 pages, 17531 KiB

Open AccessArticle

Mechanical Properties of Fly Ash-Slag Based Geopolymer for Repair of Road Subgrade Diseases

by Jia Li, Xiaotian Dang, Jingwei Zhang, Peng Yi and Yongming Li

Polymers 2023, 15(2), 309; https://doi.org/10.3390/polym15020309 - 7 Jan 2023

Cited by 11 | Viewed by 1574

Abstract

Fly ash-slag-based geopolymer is a grouting material with good fluidity and excellent mechanical and eco-friendly properties. The geopolymer can react chemically with the inert minerals of road subgrade under alkali excitation to form a good interfacial bond between road subgrade; therefore, it is [...] Read more.

Fly ash-slag-based geopolymer is a grouting material with good fluidity and excellent mechanical and eco-friendly properties. The geopolymer can react chemically with the inert minerals of road subgrade under alkali excitation to form a good interfacial bond between road subgrade; therefore, it is suitable for the repair of weak road sections. In order to solve the problems such as the difficulty to store and transport the liquid activator of existing geopolymer grouting materials and to study the unclear mechanism of the influence factors on the fluidity and mechanical properties of geopolymer; the research on the mechanical properties of fly ash-slag based geopolymer was carried out in this paper. Experiments on the preparation of geopolymer and research on different ash-slag ratios under solid alkali excitation were studied. The influence of slag content and solid alkali content (NaOH, Na₂SiO₃) on the fluidity, compressive and flexural strength of fly ash-slag-based grouting materials was also researched on the basis of single-factor gradient tests. The results showed that the slurry fluidity decreased but the compressive strength gradually increased when the content of slag was increased from 20% to 50%. With the increase in alkali content (NaOH: 2–5%; sodium silicate: 0–6%), the slurry fluidity decreased and the compressive strength increased and then decreased. Combined with the analysis of the test results of Scanning Electron Microscopy (SEM), the microscopic structures of mechanical properties of geopolymer were investigated. Lastly based on ridge regression theory, a regression model was established to predict the mechanical properties of fly ash-slag-based geopolymer. The results indicate that fly ash-slag-based geopolymer has good mechanical properties and fluidity with proper contents of slag and alkali activator, which provide a reference for experiment research and engineering application. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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22 pages, 9934 KiB

Open AccessArticle

Geopolymer Concrete with Lightweight Fine Aggregate: Material Performance and Structural Application

by Osama Youssf, Julie E. Mills, Mohamed Elchalakani, Fayez Alanazi and Ahmed M. Yosri

Polymers 2023, 15(1), 171; https://doi.org/10.3390/polym15010171 - 29 Dec 2022

Cited by 13 | Viewed by 2665

Abstract

Limited information and data are available on the material and structural performance of GC incorporating lightweight fine aggregate. In this research, three types of lightweight fine materials were utilized to partially replace sand volume of GC. These lightweight materials were rubber, vermiculite, or [...] Read more.

Limited information and data are available on the material and structural performance of GC incorporating lightweight fine aggregate. In this research, three types of lightweight fine materials were utilized to partially replace sand volume of GC. These lightweight materials were rubber, vermiculite, or lightweight expanded clay aggregate (LECA) and they were used in contents of 20%, 40%, 60%, and 100%. The variables were applied to better investigate the efficiency of each lightweight material in GC and to recommend GC mixes for structural applications. The concrete workability, compressive strength, indirect tensile strength, freezing and thawing performance, and impact resistance were measured in this study. In addition, three reinforced concrete slabs were made from selected mixes with similar compressive strength of 32 MPa and then tested under a 4-point bending loading regime. The results showed that using LECA as sand replacement in GC increased its compressive strength at all ages and all replacement ratios. Compared with the control GC mix, using 60% LECA increased the compressive strength by up to 44%, 39%, and 27%, respectively at 3, 7, and 28 days. The slabs test showed that partial or full replacement of GC sand adversely affected the shear resistance of concrete and caused premature failure of slabs. The slab strength and deflection capacities decreased by 9% and 30%, respectively when using rubber, and by 23% and 59%, respectively when using LECA, compared with control GC slab. The results indicated the applicability of GC mix with 60% LECA in structures subjected to axial loads. However, rubber would be the best lightweight material to recommend for resisting impact and flexural loads. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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20 pages, 52508 KiB

Open AccessArticle

Comparative Study on Blast Damage Features of Reinforced Concrete Slabs with Polyurethane Sacrificial Cladding Based on Different Numerical Simulation Methods

by Zhidong Liu, Xiaohua Zhao, Da Liu, Gaohui Wang and Mingsheng Shi

Polymers 2022, 14(18), 3857; https://doi.org/10.3390/polym14183857 - 15 Sep 2022

Cited by 3 | Viewed by 1786

Abstract

The defense effects of sacrificial cladding have been extensively studied in the field of blast resistance. As a polymer material with a cellular structure, polyurethane also has the potential to act as sacrificial cladding due to its good mechanical properties. The purpose of [...] Read more.

The defense effects of sacrificial cladding have been extensively studied in the field of blast resistance. As a polymer material with a cellular structure, polyurethane also has the potential to act as sacrificial cladding due to its good mechanical properties. The purpose of this study is to compare and select a numerical simulation method that is suitable for exploring the blast damage mitigation effect of polyurethane sacrificial cladding on reinforced concrete slabs. To this end, three numerical models were developed using the Fully Coupled Eulerian–Lagrangian (CEL) method, the Arbitrary Lagrangian–Eulerian (ALE) coupling method, and the Smoothed Particle Hydrodynamics and Finite Element Method (SPH–FEM) coupling method, respectively. These three numerical models were used to investigate the damage features of reinforced concrete slabs with polyurethane sacrificial cladding (PU–RCS) under contact explosions. A field test was also carried out to provide a comparison for numerical simulation results. Moreover, the advantages and disadvantages of the three simulation results and the applicability of the three coupled models were discussed. The results show that compared with the CEL model and the ALE coupling model, the SPH–FEM coupling model can better simulate the damage features of PU–RCS, such as the cracks on the bottom surface of the RC slab and the large deformation failure state of polyurethane sacrificial cladding, while the CEL model and the ALE coupling model can simulate the propagation process of shock waves and have a lower computational cost. In conclusion, the SPH–FEM coupling method is the most applicable method for exploring the blast damage features of PU–RCS in this study. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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14 pages, 4027 KiB

Open AccessArticle

Effect of Single and Synergistic Reinforcement of PVA Fiber and Nano-SiO₂ on Workability and Compressive Strength of Geopolymer Composites

by Peng Zhang, Shiyao Wei, Yuanxun Zheng, Fei Wang and Shaowei Hu

Polymers 2022, 14(18), 3765; https://doi.org/10.3390/polym14183765 - 8 Sep 2022

Cited by 46 | Viewed by 2214

Abstract

Geopolymer composites can be used as a proper substitute for ordinary Portland cement, which can reduce carbon dioxide (CO₂) emissions and make rational use of industrial waste. In this study, an investigation of the workability and compressive strength of geopolymer composites [...] Read more.

Geopolymer composites can be used as a proper substitute for ordinary Portland cement, which can reduce carbon dioxide (CO₂) emissions and make rational use of industrial waste. In this study, an investigation of the workability and compressive strength of geopolymer composites was carried out through a series of experiments, such as slump flow test, consistency meter test and compressive strength test, to clarify the interaction mechanism among superplasticizer (SP), polyvinyl alcohol (PVA) fiber, Nano-SiO₂ (NS) and geopolymer composites, thereby improving the properties of engineered composites. The results showed that with the increase in PVA fiber content, the flowability of geopolymer composites decreased, while the thixotropy increased. With the increase in the NS content, the flowability of geopolymer composites first increased and then decreased, reaching its best at 1.0%, while the thixotropy was the opposite. With the increase in the SP content, the flowability of geopolymer composites increased, while the thixotropy decreased. A significant correlation between thixotropy and flowability of geopolymer composites was found (R² > 0.85). In addition, the incorporation of single PVA fiber or NS significantly improved the compressive strength of geopolymer composites. Specifically, the compressive strength of geopolymer composites with 0.8% content PVA fiber (60.3 MPa) was 33.4% higher than that without PVA fiber (45.2 MPa), and the compressive strength of geopolymer composites with 1.5% content NS (52.6 MPa) was 16.4% higher than that without NS (45.2 MPa). Considering the synergistic effect, it is found that the compressive strength of geopolymer composites (58.5–63.3 MPa) was significantly higher than that without PVA fiber (45.2–52.6 MPa). However, the flowability and compressive strength of geopolymer composites were only slightly improved compared to that without NS. With the increase in the SP content, the compressive strength of geopolymer composites showed a trend of a slight decrease on the whole. Consequently, the results of this study may be useful for further research in the field of repair and prevention of the delamination of composite structures. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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16 pages, 7606 KiB

Open AccessArticle

Effect of Polymer Coatings on the Permeability and Chloride Ion Penetration Resistances of Nano-Particles and Fibers-Modified Cementitious Composites

by Peng Zhang, Wenshuai Wang, Yajun Lv, Zhen Gao and Siyuan Dai

Polymers 2022, 14(16), 3258; https://doi.org/10.3390/polym14163258 - 10 Aug 2022

Cited by 22 | Viewed by 2315

Abstract

Nano-particles and fibers-modified cementitious composite (NFCC) can greatly overcome the shortcomings of traditional cementitious materials, such as high brittleness and low toughness, and improve the durability of the composite, which in turn increases the service life of the structures. Additionally, the polymer coatings [...] Read more.

Nano-particles and fibers-modified cementitious composite (NFCC) can greatly overcome the shortcomings of traditional cementitious materials, such as high brittleness and low toughness, and improve the durability of the composite, which in turn increases the service life of the structures. Additionally, the polymer coatings covering the surface of the composite can exert a good physical shielding effect on the external water, ions, and gases, so as to improve the permeability and chloride ion penetration resistance of the composite. In this study, the effect of three types of polymer coatings on the water contact angle, permeability resistance, and chloride ion penetration resistance of the NFCC with varied water–binder ratios were investigated. Three kinds of polymers (chlorinated rubber coating, polyurethane coating, and silane coating) were applied in two types of coatings, including single-layer and double-layer coatings. Three water–binder ratios of 35 wt.%, 40 wt.%, and 45 wt.% were used for the NFCC. The research results revealed that the surface of the NFCC treated with polymer coatings exhibited excellent hydrophobicity. The permeability height and chloride diffusion coefficient of the NFCC coated with different types of polymer coatings were 31–48% and 36–47% lower, respectively, than those of the NFCC without polymer coatings. The durability of the NFCC was further improved when the polymer coatings were applied to the surface in two-layer. Furthermore, it was discovered that increasing the water–binder ratio of the NFCC would lessen the positive impact of polymer coatings on the durability of NFCC. Full article

(This article belongs to the Special Issue Recent Developments in Geopolymer Composites)

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