Good Weather Resistance Research Articles

A scalable and aging-resistant film for radiative cooling

Passive radiative cooling could reduce energy consumption by reflecting sunlight and radiating heat into outer space at long wave infrared. However, it is challenging that development of environmentally stable radiation-cooled materials that are easy to manufacture and have good weathering resistance. In this work, we developed a scalable radiative-cooling porous film of doped BaSO4 cellulose acetate(BSCA) with good environmental stability. The reflectivity was 0.94 with BSCA film to scatter most of the sun’s rays efficiently and an emissivity of 0.98 to radiate heat rapidly. The maximum temperature different with BSCA film were reduced by 8 ℃ less than the porous cellulose acetate (PCA) film, 13 ℃ than the commercial white paint (CWP) film. Meanwhile, in the switch boxes testing, the surface maximum temperature of the switch box coated with BSCA film were reduced by 9.9 ℃ than the switch box coated with CWP film, which were reduced by 14.7 ℃ than the original switch box. The simulated cooling power of BSCA film was 140.23 W·m−2. The BSCA film shows good optical performance and cooling performance after 3 months of outdoor aging test. The BSCA film is aging-resistant, easy to prepare and convenient for scalable production.

Controllable size of graphite nanosheets and functionalized SiO2 microspheres with excellent anti-corrosive/wear function for superhydrophobic coating

The application of superhydrophobic coatings is limited by their complex fabrication process, expensive modification, and lack of durability. This study addresses these issues by proposing a simple and economical method for fabricating strong superhydrophobic coatings by scraping off the fluorinated suspension. This coating comprises epoxy resin (EP), graphene nanosheets, and modified silicon oxide on the Q235 steel substrate. The contact angle and sliding angle of we prepare the coating coating are 152.3° and <10° respectively, exhibiting excellent super-hydrophobicity. After being immersed in 3.5 % sodium chloride solution for 1440 minutes, the coating shows a resistance of 1.14×106 Ω cm2, which is two orders of magnitude higher than that of the coating immersed for 30 minutes (1.08×104 Ω cm2), indicating its excellent corrosion resistance. A 30-day salt spray corrosion test also confirms the good corrosion resistance of the coating. When the coating is polished 100 times under a load pressure of 500 g on 1000-mesh sandpaper, the contact angle is only reduced by 7 times, indicating its good abrasion resistance. In addition, the coating also has good weather resistance and self-repairing ability against ultraviolet radiation. This simple and environmentally friendly manufacturing method has great potential for large-scale practical applications in many fields.

Preparation and characterization of UV-curable coatings based on waterborne polyurethane acrylate/g-C3N4 co-crosslinked network for wood materials

Wood materials are often damaged due to exposure to environmental factors including humidity changes, temperature fluctuations, and ultraviolet radiation, resulting in surface aging, deformation, and cracking. Therefore, developing a new wood coating with good mechanical properties and weather resistance is conducive to improving the usability and service life of wood as an outdoor material. In this study, graphitic carbon nitride (g-C3N4) with a characteristic crystal structure was synthesized using melamine as raw material. By constructing a g-C3N4 /polyurethane acrylate co-crosslinked network, a UV-curable wood coating with excellent interfacial adhesion was prepared, which retained the natural aesthetic texture of the wood and imparted good wear resistance, anti-wetting property, and aging resistance to the wood material. Subsequently, the formation process and cross-linking reaction mechanism of the coating were revealed by XRD, FTIR and XPS measurements. Compared with untreated samples, coatings with a cross-linked network structure exhibited enhanced resistance to external environmental changes. As the content of the g-C3N4 increased (>1.0 %), the mechanical properties were significantly improved, with the mass loss rate and damaged area decreasing by 56.9 % and 60.0 %. Meanwhile, with the increased cross-link density of the coating, the water and heat resistance of the wood increased by 22.77 % and 260 %, respectively. After a seven-day UV aging resistance test, the ΔE values only changed by 10.28 %, showing good weathering resistance. This design and synthesis of wood coating provides an effective technology for the long-term use of outdoor wood material.

Superhydrophilic antireflection films with excellent optical and mechanical performance for perovskite solar cells

SiO2-based antireflection (AR) films can obviously improve the transmittance of the glass cover on the solar cells. Nevertheless, it’s still challenging to fabricate SiO2 films in a facile way with great antireflective properties, high hardness and good weather resistance to ensure their long-term use in outdoor environments. To solve this problem, a double-layer broadband SiO2 antireflective film with high transmittance increase and excellent mechanical properties was successfully prepared via an acid-catalyzed sol–gel method using polyethylene glycol (PEG) as pore-forming agent. The porous PEG2000-modified SiO2 films were selected as the outer layer for coating onto the pure SiO2 film to form double-layer SiO2 films with graded refractive index. When the mass ratio of PEG2000 to TEOS was 40 %, the obtained film showed the highest transmittance increase of 3.03 % in the wavelength range of 380–1100 nm and a high hardness of 3H. After applied to the perovskite solar cell, a significant enhancement of 1.19 % in photoelectric conversion efficiency (PCE) was achieved compared to the solar cell covered with bare substrate. Furthermore, the water contact angle (WCA) was also reduced to 6° while that of pure SiO2 film was 51.3°, endowing the double-layer SiO2 film superhydrophilic and anti-fogging performance. After the weather resistance test, the transmittance loss of the film was only 0.38 %. Therefore, this work demonstrated that the use of an appropriate amount of pore-forming agent PEG and the double-layer graded refractive index structure can enhance the transmittance of acid-catalyzed SiO₂ films, while maintaining high hardness and good weathering resistance for perovskite solar cells.

Polyelectrolyte electrostatically self-assembled modified porous polyacrylonitrile nanofibers as adsorbents for anionic dye removal

Herein, we chose PAN with good sunlight and weather resistance and easy surface modification as the electrospinning material to prepare the PAN nanofiber membrane. Then the surface modification of the obtained PAN fiber membrane was carried out sequentially by alkali hydrolysis and acid neutralization to make the surface of the fiber membrane negatively charged. Finally, the positively charged polyelectrolyte PAH on the surface was selected as the functional material, and a simple and environmentally friendly electrostatic self-assembly method was adopted to modify the prepared PAN nanofiber membranes labeled as PAN@PAH. This treatment effectively increased the storage space and adsorption groups of the fiber membranes, which led to a significant increase in the removal ability of anionic dyes in wastewater. In particular, the PAN@PAH nanofiber membrane adsorbed 439.66 mg/g of methyl orange and 946.83 mg/g of Congo red, which showed better adsorption capacity than many other membranes reported in the literature. Moreover, the adsorption capacity of PAN@PAH remained at 90.19 % after eight adsorption-desorption cycles. The preparation method and modification strategy of this membrane adsorbent provides new ideas and methods for the removal of other anionic dyes.

Icephobic Coating Based on Epoxy/Polydimethylsiloxane Interpenetrating Polymer Network Gel

Ice accretion endangers the safety and reliability of equipment operation in frigid regions. Silicone polymer icephobic coatings present themselves as an effective strategy. However, they face durability challenges, which is a crucial foundation for expanding their application. In this work, a durable icephobic coating was prepared based on an epoxy/polydimethylsiloxane (PDMS) interpenetrating polymer network (IPN) gel. In the process, epoxy was used to improve mechanical performance. IPN technology was used to integrate PDMS and epoxy. Low-molecular-weight silicone oil was used to adjust the elastic modulus of the coating by reducing crosslinking. The mechanical properties, icephobicity and durability of the coatings were characterized through elastic modulus measurements, ice adhesion strength tests, and icing/deicing cycle tests, respectively. Results shows the ice adhesion strength of the epoxy/PDMS IPN gel coating was approximately 8 kPa when the elastic modulus was 0.18 MPa. Additionally, the epoxy/PDMS IPN gel has good durability, weather resistance, and substrate adhesion. After 25 icing/deicing cycle tests, the coating remained undamaged, and the ice adhesion strength was stable in the range of 3–14 kPa. Within the range of −5 to −30 °C, the ice adhesion strength of the coating was stable and less than 20 kPa. After 168 h of salt spray aging test, the ice adhesion strength of the coating was maintained at 48.72 ± 5.27 kPa. This can provide a reference for an icephobic coating design.

Self-healing polyurethane elastomer with ultra-high mechanical strength and enhanced thermal mechanical properties

Polyurethane (PU) materials are widely used due to their excellent comprehensive properties including high strength, good wear resistance and weather resistance. To further improve the service life and safety of polyurethane materials, self-healing polyurethane materials have been developed. However, self-healing polyurethane generally suffers from low mechanical strength and poor thermal mechanical properties. Here, we have constructed a strong dual network by introducing benzene-1,4-diboronic acid (PDBA) into poly(urethane-urea) (PUU). On one hand, PDBA can form coordination bonds with nitrogen atoms in PUU, leading to the formation of a dual network consisting of boron-nitrogen coordination and hydrogen bonding. This dual network imparts PUU with a maximum tensile strength of 84.2 MPa. On the other hand, boron-nitrogen coordination is more stable than hydrogen bonding at high temperature, thereby significantly enhancing the thermal mechanical properties of PUU (the mechanical strength of PUU-PDBA-50 % and PUU-PDBA-100 % increased by 1.8 times and 2.4 times, respectively, compared to PUU at 100 °C). Meanwhile, the dynamic nature of the dual network endows the material with self-healing ability.

Dynamic Recrystallization Behavior of Q370qE Bridge Steel

Bridge steel has been widely used in recent years for its excellent performance. Understanding the high-temperature Dynamic Recrystallization (DRX) behavior of high-performance bridge steel plays an important role in guiding the thermomechanical processing process. In the present study, the hot deformation behavior of Q370qE bridge steel was investigated by hot compression tests conducted on a Gleeble 3800-GTC thermal-mechanical physical simulation system at temperatures ranging from 900 ℃ to 1100 ℃ and strain rates ranging from 0.01 s−1 to 10 s−1. The obtained results were used to plot the true stress-strain and work-hardening rate curves of the experimental steel, with the latter curves used to determine the critical strains for the initiation of DRX. The Zener-Hollomon equation was subsequently applied to establish the correspondence between temperature and strain rate during the high-temperature plastic deformation of bridge steel. In terms of the DRX volume fraction solution, a new method for establishing DRX volume fraction was proposed based on two theoretical models. The good weathering and corrosion resistance of bridge steel lead to difficulties in microstructure etching. To solve this, the MTEX technology was used to further develop EBSD data to characterize the original microstructure of Q370qE bridge steel. This paper lays the theoretical foundation for studying the DRX behavior of Q370qE bridge steel.

Preparation and performance of starch-based cross-linked network structured dust suppression foams for complex climatic conditions

In complex environmental applications such as rain erosion and high-low temperatures in open-pit coal mines, the curing layer after dust suppression foam treatment is relatively poorly tolerated, resulting in poor dust suppression. This study is aimed at a high-solidification strong weather-resistant cross-linked network structure. First, oxidized starch adhesive (OSTA) was prepared by the oxidative gelatinization method to reduce the effect of the high viscosity of starch on the foaming effect. Then, OSTA, polyvinyl alcohol (PVA) and glycerol (GLY), were copolymerized with the cross-linking agent sodium trimetaphosphate (STMP), and compounded with sodium aliphatic alcohol polyoxyethylene ether sulfate (AES) and alkyl glycosides (APG-0810), a new material for dust suppression in foam (OSPG/AA) was proposed and its wetting and bonding mechanism was revealed. The results show that OSPG/AA has a viscosity of 5.5 mPa·s, a 30-day degradation of 43.564 % and a film-forming hardness of 86HA; through simulated tests in open-pit coal mine environments, it was found that the water retention of OSPG/AA is 40.0 % higher than that of water, and the dust suppression rate of PM10 is 99.04 %. The cured layer can adapt to temperature changes from −18 °C to 60 °C and remains intact after rain erosion or 24 h immersion, exhibiting good weather resistance.

Durable superhydrophobic coatings for prevention of rain attenuation of 5G/weather radomes

Superhydrophobic coatings are expected to solve the rain attenuation issue of 5G radomes. However, it is very challenging to design and construct such superhydrophobic coatings with good impalement resistance, mechanical robustness, and weather resistance, which remains as one of the main bottlenecks hindering their practical applications. Here, we report the design of superhydrophobic coatings with all these merits mentioned above by spray-coating a suspension of adhesive/fluorinated silica core/shell microspheres onto substrates. The core/shell microspheres are formed by phase separation of the adhesive and adhesion between the adhesive and fluorinated silica nanoparticles. The coatings have an approximately isotropic three-tier hierarchical micro-/micro-/nanostructure, a dense but rough surface at the nanoscale, and chemically inert composition with low surface energy. Consequently, the coatings show excellent impalement resistance, mechanical robustness and weather resistance compared with previous studies, and the mechanisms are revealed. Furthermore, we realize large-scale preparation, extension, and practical application of the coatings for efficiently preventing rain attenuation of 5G/weather radomes. By taking these advantages, we believe that the superhydrophobic coatings have great application potential and market prospect. The findings here will boost preparation and real-world applications of superhydrophobic coatings.

Environment-friendly coating with good weather resistance prepared by amorphous photonic crystals and water-dispersible resin

Traditional coatings are fabricated from chemical colorants and oleoresinous resins. However, chemical colorants and organic solvents as diluents of oleoresinous resins are pollutant for environment. Herein, environment-friendly coatings with good weather resistance are proposed by using amorphous photonic crystals (APC) and water-dispersible resins. Monodispersed silica spheres are used for producing APC and structural color. And the water-dispersible epoxy resin has a good weather resistance property. After environment-friendly coatings are submerged in toluene, acidic solution (pH = 2) and alkaline solution (pH = 12) for 2040, 840 and 840 h, respectively, the coatings are still intact, and they do not fade. The environment-friendly coatings also are able to withstand the test of 336 h under ultraviolet light. The coatings have great potential applications in displays, decorations and automotive coatings.

A study of impact induced stress due low velocity impact on laminated composite skewed hypar shell roof

The doubly ruled hypar shell, being one of the most feasible shell roof configurations, enjoys industrial preference for covering large column free areas. This class of shells is unique as the only curvature here is the cross curvature and these do not admit easy closed form solution particularly when the boundary conditions are complicated. Laminated composite, an innate choice to different industrial sectors for its huge specific strength and stiffness, good weathering resistance, is now being extensively employed in civil engineering. However the low transverse shear strength of the composite shell impelled the researchers to study the response of the same under the action of impact loads. In the present study, a finite element code is functioned to investigate the impact induced stress history generated in simply supported laminated composite hypar shell for different impact velocities of a spherical solid striker. Contact behavior is described by modified Hertzian contact law where as time dependent equations are solved using Newmark’s time integration algorithm in present analysis. A practicing engineer often has to select a particular shell option consisting stacking sequence among a number of possibilities. The present paper discusses the behaviour of composite hypars under low velocity impact and different stresses induced due to the same from engineering standpoint to propose a selection guide line among the available options and to proposes values of practical parameters like the equivalent static loads and dynamic magnification factors for designing such shells through static simplification of the problems.

Self-cleaning coating for exterior walls of concrete buildings

Due to the advantages of beautiful appearance, exterior wall real stone paint with properties of low cost and good weather resistance has been widely applied on concrete buildings for aesthetics and protection. However, the hydrophilicity of exterior wall real stone paint makes it susceptible to pollution by dust, acid rain and so on. Superhydrophobic coatings with excellent self-cleaning properties may effectively alleviate these problems, but the fabrication of real stone paint coatings with superhydrophobicity has not been reported yet. Here, the authors developed a superhydrophobic exterior real stone paint (SEP) coating with a water contact angle of 154 ± 3° and a rolling angle of 13 ± 2° through a simple and highly efficient physical blending method using an emulsion, natural sand, low-surface-energy reagents and nano-silicon dioxide (nano-SiO2). The SEP coating possessed excellent self-cleaning properties for pollutants, including soil, dust and rust water, and had good anticorrosion capability and outdoor time stability. The SEP coating also showed better solar reflectance characteristics than the normal exterior real stone paint coating, which may contribute to lowering of temperatures in buildings during hot weather and saving energy. Besides, a colorful SEP coating for decorative requirements and a large-area SEP coating for practical application could be effectively fabricated, which are expected to have promising application prospects.

Effect of Coating Process on Properties of Two-Component Waterborne Polyurethane Coatings for Wood

Acrylic acid has good environmental weather resistance, water resistance, alcohol resistance, dirt resistance, and other properties. An acrylic acid dispersion with a core–shell structure was prepared and reacted with a polyisocyanate-type curing agent to prepare a waterborne polyurethane topcoat suitable for wood. The prepared two-component polyurethane topcoat was used in combination with a waterborne primer and a waterborne sealing primer and applied to Pine (Pinus strobus) boards to carry out gloss, wear resistance, and adhesion experiments. The effects of different coating amounts and spraying times on the comprehensive properties of the wood coatings were studied. The experimental results showed that when the self-made two-component polyurethane topcoat for wood was matched with the primer and the sealing primer, the coating amount of the sealing primer had little effect on improving the adhesion and wear resistance but had a significant effect on the gloss. The spraying times of the primer and the topcoat greatly impacted the adhesion, but they had no decisive impact on the improvement of the gloss. When the coating amount was 60 g/m2 for the waterborne sealing primer, 100 g/m2 for waterborne primer, and 120 g/m2 for the self-made topcoat and the coating was sprayed twice, the comprehensive performance of the obtained film on the wood was the best. This research on the preparation and coating process optimization of the two-component waterborne polyurethane coatings for wood can provide a technical basis for the application of two-component waterborne polyurethane topcoats for wood.

Effectiveness of coal mine dust control: A new technique for preparation and efficacy of self-adaptive microcapsule suppressant

This study aims to make full use of the agricultural waste peanut shells to lower material costs and achieve cleaner production at the same time. Cellulose nanofibrils (CNF) extracted from peanut shells were mixed with acrylic acid (AA) and dimethyl diallyl ammonium chloride (DMDAAC) to prepare a new type of capsule core (dust suppressant). Then, the self-adaptive AA-DM-CNF/CA microcapsules were prepared under the action of calcium alginate. The infrared spectroscopy and X-ray diffraction analysis results suggest that AA, DMDAAC and CNF have experienced graft copolymerization which leads to the formation of an amorphous structure. The scanning electron microscopy analysis results demonstrate that the internal dust suppressant can expand and break the wall after absorbing water, featuring a self-adaptive function. Meanwhile, the laser particle size analysis results show that the microcapsules, inside which the encapsulated dust suppressant can be observed clearly, maintain a good shape. The product performance experimental results reveal that the capsule core and the capsule wall achieve synergistic dust suppression, thus lengthening the dust suppression time. The product boasts good dust suppression, weather resistance, degradation and synergistic combustion performances. Moreover, this study, as the first report on the development and analysis of dust-suppressing microcapsules, fills in the research gap on the reaction mechanism between dust-suppressing microcapsules and coal by MS simulation. The proposed AA-DM-CNF/CA dust-suppressing microcapsules can effectively lower the dust concentration in the space and protect the physical and mental health of coal workers. In general, this research provides a new insight into the structure control and performance enhancement of dust suppressants. Expanding the application range of microcapsules is of crucial economic and social benefits.

STUDY OF STRUCTURAL AND MECHANICAL PROPERTIES OF MIXED FABRICS FOR SPECIAL CLOTHING TYPE «RIPSTOP»

The article examines the indicators of the structural and mechanical properties of fabrics for special clothing of the “Ripstop” type with a mixed fiber composition. Their influence on the wear resistance of workwear was analyzed. The fiber composition of mixed fabrics for sewing military clothing includes polyester fibers and cotton fibers. At the same time, cotton fibers provide hygienic properties, and the synthetic component provides good wear and weather resistance. Mixed fabrics are easy to care for and practically do not wrinkle. The fiber composition of the textile material “Greta” of Ukrainian production includes 53% cotton fiber and 47% polyester fiber. A distinctive feature is the special interweaving of fibers, due to which the cotton fibers are on the wrong side, which improves hygienic properties. Due to the polyester fibers, the fabric is durable, resistant to pollution, and is the least prone to change in linear dimensions. It was established that the tearing characteristics of the fabric depend on the type of fibrous composition, the strength of the threads, the structure of the fabric and the methods of its processing. It was found that when stretched in the direction of the warp or weft, the strength of fabrics depends on the strength and number of longitudinal threads in the structure of the fabric, which directly accept the load. It has been studied that as the density and filling of the fabric increases, the mutual connection of its elements, that is, fibers and threads, increases, which leads to an increase in the strength of the textile material. It was established that with an increase in the thickness of the threads and the surface density of the fabric, the strength of the fabric increases. In a textile material, the threads, having mutual interweaving, are bound by friction into a single system. The use of weaves with short overlaps also contributes to the growth of fabric strength, therefore, all things being equal, the reinforced canvas weave provides fabrics with high strength. Conducted studies have shown that elongation indicators during tearing are related, first of all, to the elongation of textile fibers, which is most fully manifested in the structure of the fabric, with the twisting of yarn or threads, with interweaving.

Mechanical properties of PVC-based wood–plastic composites effected by temperature

Compared with traditional wooden building materials, polyvinyl chloride (PVC)-based wood–plastic composites have advantages of good weather resistance, easy processing capability, energy conservation, and environmental protection and have been popular and widely used in the field of civil construction and garden engineering in recent years. Due to the difference in the thermal expansion coefficient between its component materials, the stress will accumulate in the wood–plastic composites (WPCs) when the temperature changes, which will affect the mechanical properties of the material and structure. In order to explore the changes in mechanical properties of WPCs under different temperatures and achieve a safe and controllable design, the differential scanning calorimetry (DSC) method was used in this study to measure the glass transition temperature of the WPC between 78.45°C and 88.30°C, and the glass transition temperature (Tg) was about 83.54°C. The tensile, compressive, and bending mechanical property tests of PVC-based wood–plastic composite materials under different temperatures were carried out in the ambient temperature chamber to obtain the failure characteristics, the load–displacement curve, and the influence of temperature on their mechanical properties.

Effect of Fluorane Microcapsule Content on Properties of Thermochroic Waterborne Topcoat on Tilia europaea.

In a particular temperature range, 1, 2-benzo-6-diethylamino-fluorane microcapsules (fluorane microcapsules) exhibit a good color-changing function. For the coating on wood surfaces, embedding fluorane microcapsules, good weather resistance, light retention, color retention, impact resistance, and wear resistance are essential. However, the effect of fluorane microcapsule content on its properties has not been verified. Therefore, in this paper, the orthogonal test is designed with the fluorane microcapsule content, drying temperature, and drying time as test factors to identify the most influential factors. Then, by embedding microcapsules into the waterborne coating on wood substrates, the performance of the waterborne topcoat was investigated. The results show that the color of the waterborne topcoat with fluorane microcapsules on a basswood (Tilia europaea) surface can change between yellow and colorless when the temperature rises and falls, achieving reversible thermochromism. The activation temperature was 32 °C, and the range of discoloration temperature was 30–32 °C. The topcoat with a 15% fluorane microcapsule content had the best comprehensive performance. The color difference was 71.9 at 32 °C, the gloss was 3.9% at 60°, the adhesion grade was 0, the hardness was 2H, the impact resistance was 10 kg·cm, the elongation at the break was 15.56%, and liquid resistance was outstanding. After aging tests, the color difference of the topcoat with 15% fluorane microcapsules was more obvious. The damaged area of the topcoat with the addition of 15% fluorane microcapsules was smaller, indicating it had a better aging resistance. The experimental results lay the foundation for the preparation of intelligence-indicating and decorative waterborne coating.

Experimental study of the compressive properties of a wood–plastic composite at different temperatures

AbstractWood–plastic composites (WPCs) are environmentally friendly materials with good weather resistance and low cost. To investigate the feasibility of their use in different environments, a WPC was designed and subjected to a uniaxial compression test at seven temperatures to obtain the failure mode, uniaxial compressive strength, elastic modulus, proportional limit stress, peak stress, and ultimate strain. The results showed the following. The failure modes of the WPC specimens at various temperatures were mainly shear compression failure, double shear failure, and end compression failure. The uniaxial compressive strength and elastic modulus decreased with increasing temperature. Specifically, at temperatures of −60°C, 20°C (normal temperature), and 60°C, the WPC had an average compressive strength of 73.55, 33.7, and 13.51 MPa, respectively, and an average elastic modulus of 7819.11, 6141.71, and 2650.17 MPa, respectively. In terms of the WPC's stress–strain relationship, at a temperature greater than the normal temperature, the WPC had a small peak stress but good ductility; at the normal temperature and below, the WPC had a large peak stress but poor ductility. Based on these findings, the experimental phenomena and characteristic constants were analyzed to establish models of factors that reduce the uniaxial compressive elastic modulus and compressive strength of WPC at different temperatures, to provide a theoretical basis for the mechanical calculations for the application of WPC in various extreme environments.

Study on Properties of Graphene Oxide Modified Recycled Cement-Based Composites

Based on the replacement of natural sand by recycled fine aggregate of construction waste, the comprehensive physical properties and hydration mechanism of graphene oxide (GO) modified recycled cement-based composites (RCBC) were studied. The RCBC was prepared by ultrasonic dispersion GO and vibration stirring. The results show that the flexural and compressive strength of the RCBC modified by 0.03%GO at 7d age increase by 16% and 21% respectively, the flexural strength and compressive strength of RCBC modified by 0.02% GO at 28d age increase by 13.7% and 13.6% respectively. Good weather resistance and the freeze-thaw performance at age, Cl- contents is less than 0.06%. The radioactive detection results of GO/RCBC is IRa = 0.08 and Ir = 0.15, which belongs to Class A building materials. The hydration mechanism of the prepared GO/RCBC was studied by XRD, TG-DTA, SEM, and other means. The results show that GO promotes the formation of ettringite (AFt), calcium silicate hydrate (C-S-H) and the transformation of AFt and calcium hydroxide (CH) crystal form, thus improving the comprehensive properties of RCBC.