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In the field of food packaging, the addition of exfoliated layered silicates in polymers has been established to improve the polymers&rsquo, gas barrier properties. Using these polymers as coatings to protect smart textiles from oxidation and corrosion while maintaining their textile properties should significantly extend their lifetime and promote their market penetration. The aim of this study was to print new polymer dispersions containing layered silicates to protect screen-printed conductive structures, and to test the resulting samples. For this, appropriate printing parameters were determined by statistical design of experiments. According to these results, conductive structures were printed and protected with the selected coating. The abrasion resistance and the continuity of the protective layer of the printed samples were then measured. A continuous protective coating of approximately 70&ndash, 80 &micro, m thickness was applied on a conductive structure. The printed samples showed a very high resistance to abrasion (unchanged by 85,000 abrasion cycles) while remaining flexible and presenting a lower water vapor permeability (&lt, 2.5 g/m&sup2, d) than the coatings commonly used in the textile field.

Combining textile fabrics with 3D printing has been investigated intensively during the last years. Mostly, research concentrated on the adhesion between both partners of the composite or on the new freedom of design, enabled by combining these techniques. Here, we present examinations of the influence of elastic 3D printed patterns on the elongation and wearing out of elastic textile fabrics as well as on the tribological properties of the textile surface, comparing pure and imprinted textile fabrics. Therefore, thermoplastic polyurethane (TPU) was 3D printed in different patterns on diverse textile fabrics. Our study shows that for a sufficient adhesion, reached by small enough nozzle-fabric distance, elastic 3D printed patterns can indeed improve the surface resistance against wear.

Structural color as a revolutionary coloration strategy has been proposed to replace the traditional dyeing and printing process. However, the poor colorfastness and easy crack formation of structural colors on textile fabrics restrict their practical application at present. In this study, poly (tert-butyl acrylate-co-glycidyl methacrylate) (P(t-BA-co-GMA)) copolymers containing reactive epoxy groups with different mass ratios of tert-butyl acrylate (t-BA) and glycidyl methacrylate (GMA) were successfully synthesized, which were used to create structural colors on black polyester fabrics. The results showed that P(t-BA-co-GMA) nanospheres could form crack-free structural colors on polyester fabrics, and the colors vary with the mass ratio of t-BA and GMA to obtain five different colors. The different particle sizes of the different P(t-BA-co-GMA) nanospheres with different refractive indexes and the arrangement of short-range ordered and long-range disordered in microstructures may be the reason of different angle-independent structural colors on polyester fabrics. The P(t-BA-co-GMA) nanosphere structural colors on polyester fabrics possess good abrasion and washing colorfastness. This research provides the experimental basis for the development of crack-free amorphous photonic crystal structural color on fabrics with high colorfastness to promote the practical application of structural color in textile coloration.

We measured hardness, modulus of elasticity, and, for the first time, loss tangent, energy of fracture, abrasion resistance, and impact resistance of zinc- and manganese-enriched materials from fangs, stings and other “tools” of an ant, spider, scorpion and nereid worm. The mechanical properties of the Zn- and Mn-materials tended to cluster together between plain and biomineralized “tool” materials, with the hardness reaching, and most abrasion resistance values exceeding, those of calcified salmon teeth and crab claws. Atom probe tomography indicated that Zn was distributed homogeneously on a nanometer scale and likely bound as individual atoms to more than ¼ of the protein residues in ant mandibular teeth. This homogeneity appears to enable sharper, more precisely sculpted “tools” than materials with biomineral inclusions do, and also eliminates interfaces with the inclusions that could be susceptible to fracture. Based on contact mechanics and simplified models, we hypothesize that, relative to plain materials, the higher elastic modulus, hardness and abrasion resistance minimize temporary or permanent tool blunting, resulting in a roughly 2/3 reduction in the force, energy, and muscle mass required to initiate puncture of stiff materials, and even greater force reductions when the cumulative effects of abrasion are considered. We suggest that the sharpness-related force reductions lead to significant energy savings, and can also enable organisms, especially smaller ones, to puncture, cut, and grasp objects that would not be accessible with plain or biomineralized “tools”.

The impact of heat treatment process (HT) on microstructural, mechanical and tribological performance of unalloyed and alloyed ductile iron has been investigated. Austenitizing temperature at 900 °C/350 °C/30min, 920 °C/350 °C/30min, 950 °C/350 °C/30min and 970 °C/350 °C/30min were deployed respectively, after which the specimens were furnace cooled to room temperature. The highest ultimate tensile strengths of 598.9 and 519.75 Mpa were recorded for both unalloyed and alloyed ductile iron (DI) at 920 °C/350 °C/30min. The DI heat-treated at 950 °C/350 °C/30 min from the Charpy impact test had the highest energy value of 10 J. The optical microscope and SEM micrographs show that heat-treatment process produced some ferrite and martensitic structures; some bull eyes and nodules are also evident on the microstructures. The highest frictional coefficient value of 9.10 × 10−1 was obtained for DI matrix while 8.0 × 10−1, 6.0 × 10−I, 4.0 × 10−1 and 2.0 × 10−1 were recorded for specimens heat-treated at 900 °C/350 °C/30min, 920 °C/350 °C/30min, 950 °C/350 °C/30min and 970 °C/350 °C/30 min, respectively. In addition, the tribological behavior of the heat-treated DI under 10 N loads showed a dual wear process comprising abrasion and oxidation. The wear behavior of the heat-treated microstructure in the matrix corresponds to the strengthening and toughening effect under the same load. However, the mechanical testing of the samples confirmed an improvement in the hardness, impact, and tensile strength of the samples. The significance of annealing heat treatment is demonstrated in this study, as its consistent impact is evident in all the mechanical tests conducted on the specimens.

In this work, a durable superhydrophobic fabric was fabricated by a facile covalent surface modification strategy, in which the anchoring of 10-undecenoyl chloride (UC) onto the fabric through the esterification reaction and covalent grafting of n-dodecyl-thiol (DT) via thiol-ene click chemistry were integrated into one step. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) measurement results demonstrated that UC and DT were covalently grafted onto the fabric surface. The formed gully-like rough structure by the grafted UC and DT on the fabric surface together with the inherent microfiber structure, combined with the grafted low-surface-energy materials of UC and DT, gave the resultant modified DT-UC@fabric superhydrophobic performance. The superhydrophobic DT-UC@fabric was used for separation of oil-water mixtures; it exhibited high separation efficiency of more than 98%. In addition, it presented excellent durability against mechanical damage; even after 100 cyclic tape-peeling and abrasion tests, the DT-UC@fabric could preserve superhydrophobic performance, which was ascribed to the formed covalent interactions between the fabric surface and the grafted UC and DT. Therefore, this work provided a facile, efficient strategy for fabricating superhydrophobic composites with excellent durability, which exhibited a promising prospect in the application of self-cleaning and oil-water separation.

Low moisture absorbency of hydrophobically coated flame-resistant (FR) fabrics do not correlate well with the thermophysiological comfort. In this frame, we were the first to study the effect of screen-printed microfibrillated cellulose (MFC) on fabric’s breathability and moisture build-up and transfer as user-friendly and wear-related comfortable coating. The amount of MFC applied and its patterning was varied using different printing parameters, and the density and thickness of FR fabric, and studied by add-on measurement and microscopic imaging. The effect of MFC coating and its durability (attachment) after a post-printing of hydrophobic polyacrylate on the same (layer-by-layer) or other side of the fabrics was considered, thus to maintain one side of the fabric (facing towards the wearer) hydrophilic while keeping the other side (facing outward) hydrophobic. The results showed that MFC provides uniform and repeatable printing, which gave homogeneous patterning with good layering on the fabrics, although, resulting in the MFC concentration, squeegee’ pressure, and fabric’ structure dependent add-on, its imprinting and co-crosslinking within the polyacrylate. This slightly reduced the fabric air-permeability, but increased it surfaces wetting, moisture uptake kinetic and capacity (hydroscopicity), without affecting the water vapour transfer. Besides, the polyacrylate could fix the MFC pre-printed on the other side of the fabric, thus maintaining its hydrophilicity, being more pronounced in the case of less open and thicker fabric, while improving its tensile /tear strengths and abrasion resistance, without deterioration of the fabric`s flammability.

Downhole heavy oil production and oil sand processing are associated with severe damage and failures of production equipment components, e.g., production tubing and pumping systems, due to erosion-corrosion resulting in processing losses, production downtime, high maintenance and replacement cost. Protective coatings (layers) on the production components mostly fabricated from low-alloy steels can be applied to minimize these problems. In the present work, the performance of hard boronized coating on carbon steel obtained through the thermal diffusion process and consisted of two iron boride layers (FeB and Fe2B) was studied in synergistic erosion-abrasion-corrosion conditions simulating oil production environment in comparison with bare steel. Special wear testing equipment was designed and fabricated. In this testing, the inner surface of tubular sections was subjected to high velocity erosive flows of water-oil slurries containing silica sand and salts combined with rotating and oscillating motions of steel pony rods. Structural examination of the studied materials’ surfaces and their profilometry after wear testing were conducted. The iron boride coating demonstrated significantly higher performance in abrasion and erosion-abrasion-corrosion conditions compared to bare carbon steel due to its high hardness, high chemical inertness, dual-layer architecture and diffusion-induced bonding with the substrate. The boronized steel tubing and casing with inner surface protection can be effectively employed in the most critical operation conditions.

Abstract Developing high-performance separation membrane with good durability is a highly desired while challenging issue. Herein, we reported the successful fabrication of chemically and mechanically durable superhydrophobic membrane that was prepared by embedding UiO-66 as size-sieving sites within the supramolecular fiber structure of collagen fiber membrane (CFM), followed by the polydimethylsiloxane (PDMS) coating. The as-prepared CFM/UiO-66(12)/PDMS membrane featured capillary effect-enhanced separation flux and homogeneous porous channels guaranteed high separation efficiency. When utilized as double-layer separation membranes, this new type of composite membranes separated various surfactant stabilized water-in-oil microemulsions and nanoemulsions, with the separation efficiency high up to 99.993 % and the flux as high as 973.3 L m− 2 h− 1. Compared with commercial polytetrafluoro ethylene (PTFE) membrane, the advantage of the double-layer CFM/UiO-66(12)/PDMS membranes in separation flux was evident, which exhibited one order of magnitude higher than that of commercial PTFE membrane. The CFM/UiO-66(12)/PDMS membrane was acid-alkali tolerant, UV-aging resistant and reusable for emulsion separation. Notably, the CFM/UiO-66(12)/PDMS membrane was mechanically durable against strong mechanical abrasion, which was still capable of separating diverse water-in-oil emulsions after the abrasion with sandpaper and assembled as double-layer separation membranes. We anticipate that the combination of CFM and metal organic frameworks (MOFs) is an effective strategy for fabricating high-performance separation membrane with high mechanical and chemical durability. Graphical Abstract

The aim of the study was to develop composite film materials derived from modified sodium carboxymethyl cellulose and to evaluate their anti-adhesive effects. Materials and Methods. The modified film materials were obtained by dissolving sodium carboxymethyl cellulose (Na-CMC) in an aqueous solution of a modifier (glycoluril) with subsequent homogenization and drying in a vacuum drying oven at room temperature. Physicomechanical parameters of the obtained films were determined using the Instron 3369 universal electromechanical testing machine (Great Britain) equipped with a climatic chamber (300–523 K), improved video extensometer, and the MKC-25 micrometer (Russia). Cytotoxicity of glycoluril-modified film materials derived from Na-CMC was studied by incubating cell cultures of 3T3-L1 mouse fibroblasts directly with extracts from films under study using a colorimetric test. Their anti-adhesion effect was investigated on 40 female Wistar rats by modeling a flat adhesion by inducing abrasion of the cecum and suturing the deserosed surface of the abdominal wall anatomically opposite the abrasion area. The presence of adhesions was assessed on day 8 after the operation. Commercial membrane Seprafilm (USA) was used as a reference sample. Results. It was found that extracts obtained from film materials derived from Na-CMC modified with glycoluril at a concentration of 0.01 and 0.05 wt. % had no cytotoxic effect on the cell culture of mouse fibroblasts 3T3-L1. Flat adhesions were not detected when using Seprafilm. When film materials under study were placed in the abdominal cavity between the injured areas, formation of flat adhesions was not observed or observed in one case out of ten. Conclusion. The obtained films are promising for preventing adhesions as a barrier-type agent. Modifying Na-CMC with glycoluril made it possible to create films that prevent formation of flat adhesions, have improved physical and mechanical properties and no cytotoxic effect.

Geopolymer is emerging as a potential alternative material to the ordinary Portland cement (OPC) owing to its energy efficiency and environmental protection. However, the effect of the mix design parameters on the behavior of geopolymer concrete (GPC) produced using local metakaolin (MK) is not well established. This paper presents findings from a comprehensive experimental program to study the effect of various mix design parameters on the properties of fresh and hardened MK-based GPC. Seventeen mixes were cast in four groups to investigate the effect of four parameters, including sodium silicate to sodium hydroxide ratio, alkaline solids to MK ratio, aggregate content, and water to solids ratio on the properties of GPC. The investigated properties included workability, density (wet and dry), development of compressive strength with age, splitting tensile strength, ultrasonic pulse velocity, water absorption, and horizontal abrasion resistance. Besides, two reference OPC concrete mixes, equivalent to two MK-based geopolymer mixes, were tested for the sake of comparison. The test results were helpful in developing a better understanding of the behavior of MK-based GPC. Some useful models are proposed for predicting workability, splitting tensile strength, water absorption, and weight loss in abrasion for MK-based GPC. The test results were supplemented and confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis performed on some selected GPC mixes.

In a marine environment, the working conditions for carbon brush and slip-ring system are complicated, leading to carbon brush abrasion and a shortened replacement cycle. A research and experiment platform using a salt spraying tester has been established to study abrasion on the carbon brush and slip-ring system of a Doubly-fed machine. We conducted tests on the carbon brush and slip-ring system contact current, contact pressure, concentration of salt spray, and the experimental temperature. The improved Coulomb-viscous friction model was adopted for modelling the carbon brush abrasion. The contact current, contact pressure, salt spray concentration and temperature were introduced as the test conditions for the forecast model, and the unknown model parameters were identified through the least square method. MATLAB was utilized to fit the nonlinear model parameters using the carbon brush abrasion prediction model results. The residual error plot and test data fitting indicated that the prediction model could effectively forecast the carbon brush abrasion loss under various conditions.

To improve the properties of silica-reinforced truck tire tread compounds, especially abrasion resistance, the effect of vinyl contents in butadiene rubber (BR) or solution styrene–butadiene rubber (SSBR) as secondary polymers in silica-filled natural rubber (NR) compounds at a ratio of 80/20 phr is investigated in the first part of this study. By increasing the levels of vinyl contents in BR in combination with NR, a better Payne effect, 300% modulus, reinforcement index, and tan delta at −20 and 0 ° C are obtained, whereas the tensile strength, elongation at break, and DIN abrasion resistance index decrease with increasing vinyl contents. Higher vinyl contents in SSBR result in improvements in Payne effect, 300% modulus, tan delta at −20 and 0 °C but only a small improvement in DIN abrasion resistance index. Combinations of secondary fillers and polymers in silica-filled NR are covered in the second part of present study. Silica/carbon black–filled NR/BR and NR/SSBR, respectively, and silica/organoclay–filled NR/BR and NR/SSBR show positive effects on scorch time and optimum cure time, with only slight changes in Payne effect, tensile properties, tan delta at −20 and 0 ° C and DIN abrasion resistance as compared with compounds with carbon black N134. The use of organoclay results in an enhanced Payne effect and tan delta at 60 °C, indicative of reduced filler–filler networking and consequently a lower rolling resistance of tire tread compounds as compared with the compound without organoclay. The specific combination of a small amount of organoclay replacing the same amount of silica, together with some of the NR replaced by high-vinyl BR, promises a substantial overall boost in wet and ice traction, abrasion, and wear resistance as compared with straight NR/silica tire treads. This new observation helps to overcome one of the main shortcomings of NR/silica compounds: their generally low wear resistance.

Engineering for the cement industry is part of the heavy industry. The cement industry is the main supplier of raw materials for the production of concrete and reinforced concrete. For grinding cement, two types of mills are used - ball and roller. Recent decades have proven the great effectiveness of a vertical roller mill for grinding raw materials. Its effectiveness, combined with the implementation of drying, grinding and separation in one unit, gives it an undeniable advantage over a ball mill. This explains the significant increase in the share of roller mills in the cement mill market. The grinding process in such mills occurs due to abrasion, respectively, in the process of work wear of the rubbing parts of the mill occurs. The work evaluated the performance of a mill with smooth disk rolls. During the study, the cause of the destruction of the sectors of the mill produced by FLSmidth, operating in the Russian Federation, was identified. The study revealed the causes of the destruction of the details of the roller mill: with the simultaneous impact of the workload and the displacement of the sectors resulting from intensive wear, the total equivalent stresses exceed the value of the endurance limit under cyclic loading. Therefore, the accumulation of fatigue damage to the material, the formation and growth of cracks, which adversely affects the performance of the mill. A number of measures have been proposed to increase the operability of mills of this design.

Abrasion protection in exposed areas is a common method of extending the life cycle of textile products. To achieve sufficient abrasion resistance, the textile products are usually coated or partially printed with hard products. But hard materials lead to stiffening and can have a negative effect on the haptics. The aim of this study is the application of abrasion-resistant and compressible print patterns directly to textile substrates by 3D printing. The compressibility is achieved by the inner structure, which, in contrast to conventional coatings, is not 100 % filled. In the investigations, four thermoplastic materials were tested for their abrasion resistance and compressible properties. Fabrics made of cotton or polyester/cotton blends were used as textile substrates. Different approaches were taken to create the structures, some of which can only be realized using 3D printing technology. The abrasion resistance of the substrates could be increased from 50 abrasion cycles to over 8,000 cycles with the help of the 3D printed patterns. It was possible to print 3D structures that could be compressed in thickness by up to 53 %. The combination of both properties, abrasion resistance and compressibility, can be used for new types of individual products with good wearing comfort and functionality that meet the requirements, especially in the areas of functional, protective and sports clothing.

The cooling rate during fabrication affects the microstructural features and interface strength in metal matrix composites (MMCs). Thus, the present investigation is focused on characterizing the effect of quenching medium on wear and friction response of self-lubricating Al-Cu dual matrix composites. Mica was reinforced in Al-Cu metal matrix composites with the variation of weight percentage as 1%, 2%, 3%, 5%, 8% and 10%. A standard powder metallurgy route was adopted for fabrication. The sintered composites were normalized, and quenched in water, and oil. A pin on disc study was carried to investigate the friction and wear behavior of normalized, oil quenched, water quenched and as-prepared (green) composites. The results revealed that oil quenched composites exhibited the lowest friction coefficient and highest wear loss. The highest friction coefficient of ~0.8 was observed for normalized composites, whereas the highest friction coefficient for water quenched composites was ~0.6. The oil quenched composites exhibited about 8 ~ 15 times higher wear loss as compared to normalized and water quenched composites. Worn surfaces were analyzed under a scanning electron microscope to know the dominant wear mechanisms. The developed composites find potential applications in automotive industry such as pistons for petrol and diesel engines.

Microsurfacing has recently been accepted widely as an effective method for preventive maintenance of pavements. Microsurfacing is a mixture of cationic polymer-modified bitumen emulsion, 100% manufactured well-graded fine aggregate, mineral filler, water, and chemical additives. In this research, in order to evaluate the performance of steel slag in microsurfacing mixture, two types of bitumen emulsions (cationic quick setting and cationic slow setting) were used together with three types of mixtures in which 100% siliceous aggregate was used as a control mixture and then steel slag was replaced by 61% and 100% aggregate of control mixture. The performance of the samples was evaluated by experiments included wet cohesion test, wet track abrasion test, and loaded wheel test, according to international slurry surfacing association (ISSA) A143 guideline and ASTM D6372 standard. The results of tests showed that steel slag aggregate has proper compatibility with both of bitumen emulsion types judged by its desirable physical, chemical, and mechanical properties. The alkali characteristic of the steel slag leads to a stronger adhesion of these materials to acidic bitumen and cause prevented the stripping in the vicinity of water in comparison to the control mixture. Also, steel slag-containing mixtures displayed a more appropriate behavior in terms of rutting and stripping distresses. Keywords: Microsurfacing, Steel slag aggregate, Abrasion resistance, Aggregate and bitumen adhesion

Background To compare the effect of Er:YAG Laser and Air particle abrasion (APA) surface treatments on shear bond strength of Y-TZP to composite resin cuboids in the presence and absence of primer application and salivary contamination. Material and methods Seventy-two cuboidal shaped specimens 7x7x3 were prepared from Y-TZP using CADCAM, cleaned and sintered. Specimens were divided into 2 main groups (n=36) according to surface treatment method; Air particle abrasion (A) and laser (L). Each group was subdivided into 2 subgroups (N = 18) according to surface modification using primer; each subgroup was further divided into 2 subdivisions (N=9) according to the presence of salivary contamination; APC (Air particle abrasion, primer, contamination), AP (Air particle abrasion, primer), AC (Air particle abrasion, contamination), A (Air particle abrasion), LPC (Laser, primer, contamination), LP (Laser, primer), LC (Laser, contamination), L (Laser). Composite cuboids having dimensions of 6x6x3 were also fabricated using custom made plexi plates. Composite cuboids were cemented centrally to zirconia cuboids and light cured under 5 kg weight for 6 mins. Shear bond strength of specimens was measured utilizing universal testing machine at a crosshead speed of 0.5 mm/min. Failure loads were recorded in Newton. SBS was calculated according to equation: SBS (MPa) = load (N)/area(mm2). Results Viewing shear bond strength between studied groups, group APNC (484.02±85.02) showed higher mean value compared to ANPNC (122.09±55.80), also LNPNC (120.87±65.10) showed higher mean value in comparison to LPNC (170.78±53.22). APNC (484.02±85.02) and APC (592.22±189.65) showed higher mean values than LPNC (170.78±53.22) and LPC (3227.66±108.28) in sequence. Conclusions APA showed higher SBS values than Er:YAG surface treatment. Primer showed better results than no primer coating. Artificial saliva contamination did not affect the SBS of zirconia compared with no contamination results. Key words:Shear bond strength, zirconia, air particle abrasion, Er:YAG laser, primer, contamination.

Introduction: Composite resins have developed in past years, however, failures may occur which needs whole restoration repairing. this study aimed to evaluate the effect of different surface treatments on shear bond strength of new to old composite restorations. Materials and Methods: A total of 60 blocks of Z250 composite resin were divided to four groups 1) no surface preparation (control group), 2) abrasion through aerosols using 50-micron aluminum oxide particles, 3) abrasion through diamond milling with 125-micrometer particles, 4) surface preparation using hydrofluoric acid. Shear bond strength in different methods such as etching with hydrofluoric acids (with and without silanization), air abrasion, and diamond milling was compared with the control group. All data were analyzed using the Kolmogorov-Smirnov test and one-way analyses of variance (ANOVA) and Tukey’s post hoc test. Results: In comparing the groups with each other, it was found that shear bond strength in Hydrofluoric acid and silanization group was significantly higher than control (P = 0.017). Conclusion: The effects of etching with hydrofluoric acid and silanization in increasing shear bond strength between aged and new composite resins are superior to control, which could be a suitable repair protocol to obtain optimal repair bond strength.

Promoting the martensitic transformation through optimum microalloying with Fe and/or Mn was observed to be an effective method to enhance the wear resistance of the Cu50Zr50 at% shape memory alloy (SMA). Among all the potential microelements and concentrations, partial replacement of Cu by up to 1 at% Fe and Mn is of interest since from density functional-based calculations, large minimization of the stacking fault energy (SFE) of the B2 CuZr phase is predicted. For this reason, an effective martensitic transformation is expected. The largest decrease of the SFE from 0.36 J/m2 to 0.26 J/m2 is achieved with partial replacement of Cu by 0.5 at% Fe. This results in the highest martensitic transformation upon wear testing, especially at highest load (15 N) for which the mass loss is 0.0123 g compared to 0.0177 g for Cu50Zr50 and a specific wear-rate of 5.9 mm3/Nm, compared to 8.5 for mm3/Nm for Cu50Zr50. This agrees with the low coefficient of friction of 0.48 ± 0.05 and low roughness of 0.200 ± 0.013 µm of the Fe-containing alloy compared to that for Cu50Zr50, 0.55 and 0.415 ± 0.026 µm, respectively. All the worn surfaces show the formation of abrasive grooves, being shallowest for the more wear resistant 0.5 at% Fe alloy. The second more wear resistant alloy contains 0.5 at% Mn. Wear mechanisms of abrasion, adhesion, and delamination have been identified.

Coatings prepared from chromia-rich (Al,Cr)2O3solid solution (ss) feedstock powders are intended to improve the properties of Cr2O3coatings, but are rarely studied so far. In this work, the processability of a commercial (Al,Cr)2O3solid solution (ss) powder containing 78 wt.% Cr2O3by atmospheric plasma spraying (APS), the corresponding coating microstructures and properties were investigated. Possible further improvements were expected by blending with 2, 23 and 54 wt.% TiOxpowder. For comparison, plain Cr2O3and TiOxcoatings were studied as well. The microstructures were analyzed using SEM, EDS and XRD measurements. Hardness (HV0.3) was measured, as well as the dry unidirectional sliding wear resistance and the abrasion wear resistance (ASTM G65). Moreover, the corrosion and electrical insulating properties were measured. The (Al,Cr)2O3ss showed only a small change of the composition, and the formation ofγ-Al2O3, as found for alumina-rich (Al,Cr)2O3ss powders, was avoided. Compared to the plain chromia coating, some improvements of the processability and coating properties for the ss (Al,Cr)2O3coating were found. The most balanced coating performance was achieved by blending the ss (Al,Cr)2O3with 2 wt.% TiOx, as this coating showed both a high sliding and abrasion wear resistance, in combination with a high corrosion resistance.

В статті містяться результати випробувань основних типів сталей при терті по нежорстко закріплених частинках абразиву В статье содержаться результаты испытаний основных типов сталей при трении о нежостко закрепленные абразивные частицы The article contains the results of tests of the main types of steels by friction on non-rigidly fixed abrasive particles. The steel presents a wide field of application. The abrasive wear resistance of steel relies mainly on the microstructure, hardness as well as on the abrasive material properties. Moreover, the selection of a abrasion-resistant grade of steel still seems to be a crucial and unsolved problem, especially due to the fact that the actual operating conditions can be affected by the presence of different abrasive materials. The aim of this work was to determine the effect of different abrasive grit materials i.e. garnet, corundum and carborundum on the abrasive wear result of a commonly used in industry practice steels i.e. S235, S355, C45, AISI 304 and Hardox 500. The microstructure of the steel was investigated using light optical microscopy. Moreover, hardness was measured with Vickers hardness tester. Additionally, the size and morphology of the abrasive materials were characterized. The abrasion tests were conducted with the usage of T-07 tribotester (dry sand rubber wheel). The results demonstrate that the hardness and structure of steels and hardness of abrasive grids influenced the wear results. The abrasive wear behavior of steels was dominated by microscratching and microcutting wear mechanisms. The highest mass loss was obtained for garnet, corundum, and carborundum, respectively. The usage of various abrasives results in different abrasion resistance for each tested steel grade. The AISI 304 austenitic stainless steel presents an outstanding abrasive wear resistance while usage of corundum and Hardox 500 while using a garnet as abrasive material. The C45 carbon steel was less resistant than AISI 304 for all three examined abrasives. The lowest resistance to wear in garnet and carborundum was obtained for the S235JR and S355J2 ferritic-perlitic carbon steels and in corundum for Hardox 500 which has tempered martensitic structure.

A new experimental method on simulating the combined action of cavitation erosion and abrasion was proposed to investigate the erosion mechanism of overflow structure induced by the said processes. An automatic sand mixing device was invented for high-pressure and high-speed flow based on the characteristics of Venturi cavitation generator and hydraulic Bernoulli principle. The experimental system for the combined action of cavitation erosion and abrasion was designed and constructed, and high-speed sand mixing flow only appeared in the test section. A series of tests on the combined and single action of cavitation erosion and abrasion on hydraulic concrete and cement was carried out by using the invented experimental device. Results show that the wear of concrete surface exhibited the combined characteristics of cavitation erosion and abrasion under their joint action. The damage degree of concrete surface under the combined action was more severe than that under a single action. The mass loss of concrete under the combined action was higher than sum of mass losses of concrete under two single actions. The promotion and enhancement between cavitation erosion and abrasion existed in high-speed sand mixing flow. A power exponential relationship was observed between erosion mass loss and flow speed, and the velocity indexes approximated 4.5. Small and light sand particles easily follow water flow. Thus, the strong coupling effect of cavitation erosion and abrasion resulted from the presence of small sand particles. Given the different mechanisms of cavitation erosion and abrasion, presenting the skeleton structure formed by cavitation erosion was notably difficult under the action of abrasion. Meanwhile, abrasion wear easily occurred under the impact of cavitation erosion, and this result is due to the mechanism of the combined action of both processes.

A novel ultralight superhydrophobic-superoleophilic hybrid Carbon Nanotubes (CNTs) film with double-layer structures is fabricated by using vacuum filtration method. The CNTs film can separate various surfactant-stabilized water-in-oil emulsions with a separation efficiency higher than 99.3%. Moreover, the hybrid films can be regenerated through a simple and rapid combustion process within 2 s. In addition, the CNTs film still retains good hydrophobic properties under the conditions of physical abrasion, and strong acidic and alkaline solutions, which shows the excellent durability. The hybrid CNTs film is ultralight, stable, and easily stored and reused. The outstanding features of the obtained CNTs films we present here may find many important applications in various fields like oil purification and wastewater treatment.

The ASTM C1138 standard underwater abrasion test can be considered as the best available experimental tool to qualitatively evaluate the abrasion resistance of concrete surfaces in hydraulic structures. It introduces an accelerated test procedure to simulate the high speed motion of water and waterborne materials on concrete surfaces. However, the test period is relatively long, which is composed of 6 time steps of 12 h each, totaling a complete 72 testing hours for each sample. Thus, although of the simple test procedure and good potential to simulate real abrasion in hydraulic structures, it is difficult to perform and requires a long time if many concrete samples are needed to be compared. At the aim of investigating the possibility of reducing the total testing time of ASTM C 1138, an experimental work was conducted in this research. Three concretes with low strength (LSC), normal strength (NSC) and high strength (HSC) were tested at different rotational speeds of 800, 1200 and 1600 rpm. The test results showed that increasing the test speed from the standard 1200 rpm–1600 rpm resulted in an average increase in an abrasion weight loss of 42.6–47.0%, which encourages the possibility of reducing the total testing time by 40 % if the test is performed at a speed of 1600 rpm. The test results of this study and others from the literature showed that the relationship between the abrasion weight loss and testing time (up to 72 h) can adequately be represented using a linear correlation. The R2 values of the linear correlations of 16 different concrete mixtures ranged from 0.936 to 0.999. Based on the obtained results, a simplified modified test procedure was suggested to reduce the total testing time from 72 h to 15 h.

This paper reports the long-term field and laboratory-tested performance of concrete produced with 20 wt% replacement of cement with powder waste glass (WG). Field investigations of WG concrete were carried out in a large-scale field project comprising of various segments subjected to harsh weathering conditions and service load over a period of about three years. While laboratory cured WG concrete and normal concrete specimens were tested in compression and flexure at various concrete ages ranging from 3 days to 300 days. After about three years of field exposure, concrete cores were extracted from various segments of the project and tested for compressive strength, moisture sorption, and abrasion resistance. A detailed survey of the various segments of the project was carried out to physically examine the state of WG concrete after three years of service. Test results of the field WG concrete showed enhanced compressive strength, up to 57% reduction in moisture sorption and up to 61% reduction in abrasion weight loss in comparison to normal concrete at 300 days of concrete age. Similarly, the laboratory tests showed 43% gain in compressive strength and 28% gain in flexural strength of WG concrete in comparison to that of normal concrete at 90 days of concrete age. Detailed physical examination of various project segments showed no signs of deterioration or material failure after three years of service. The field project also demonstrated the constructability of WG concrete similar to that of normal concrete.

In this paper, the utilization of recycled asphaltic concrete aggregate (RACA) in high calcium fly ash geopolymer concrete (HFGC) was explored. Coarse limestone aggregate was replaced with RACA at 0, 20, and 40 %by weight of the aggregate. The 10 M NaOH (NH), sodium silicate (NS), NH/NS ratio of 1.0, liquid alkaline/ash ratios of 0.45, 0.55, 0.65 and 0.75 were used to make geopolymer concrete cured at 25 °C. Test results indicated that the compressive strength decreased with the increase in RACA content as expected. However, the surface abrasion and sulfuric acid resistances were improved due to the presence of the adhered asphalt and the associated reduction in porosity and water absorption of the HFGC. The other benefit is the reduction in thermal conductivity due to the intrinsic low thermal conductivity of asphalt and RACA. The RACA could thus be beneficially utilized to improve the performance of geopolymer concrete with slight reduction in compressive strength but enhanced surface abrasion and sulfuric acid resistances.

Superhydrophobic surfaces integrated with liquid self-repelling property have great application potential, nevertheless, it remains a major challenge for simultaneously achieving super-robust feature and extreme superhydrophobicity. In this work, a super-robust self-healing superhydrophobic coating containing cyclic olefin copolymer (COC), fluorinated alkyl silane (FAS) and polytetrafluoroethylene (PTFE) nanoparticles, is prepared by a convenient one-step wet-chemical coating method. The treated fabric has water contact angle of 168˚and sliding angle of 3˚. The coating demonstrates excellent endurance to various severe damages, e.g., repeated washing, abrasion, boiling water, strong UV irradiation, extremely high and low temperature. It also shows self-healing capability from physical/chemcial damages. Benefitting from the triboelectric negative features of COC and PTFE, this coating shows triboelectrification induced water self-repellence after rubbing with a polyamide (Nylon) fabric, water droplets can jump/move off the tribo-charged area. Moreover, this self-repelling feature works with many different aqueous liquids, such as NaCl, strong acid and alkali. Such a robust superhydrophobic coating can be applied onto many other substrates, such as cotton fabric, glass and cotton, and the treated substrates also exhibited liquid self-repellent properties after rubbing with a Nylon fabric. This triboelectrification enhanced superhydrophobic coating might shed light on developing energy-efficient liquid self-removing surfaces for various applications.

The use of burnt bricks is gradually becoming popular in the Ashanti region in Ghana. This is evident with the increased number of burnt brick manufacturing sites in the region. However, the quality of the manufactured burnt bricks is not known. The study aims at assessing the quality of burnt bricks produced in the Ashanti Region of Ghana. 200 bricks samples were randomly selected from five brick production sites for their properties to be determined and compared with standards and previous studies’ requirements. The bricks were physically examined for regular shape, size variation, and surface crack; and tested for dry density, compressive strength, split tensile strength, water absorption, and abrasion coefficient. The bricks were observed to have regular surfaces with some visible cracks and reduced size variations beyond the tolerance level. The densities of the burnt bricks (1548.84–1988.61 kg/m3) were found to be satisfactory. The compressive strength of 10.27–19.71 MPa, and split tensile strengths of 1.50–2.88 MPa were within the class designation for burnt bricks. The water absorption of 3.30–8.25%, and abrasion resistance of 1.48–2.04 cm2/g met the requirement of burnt bricks. The study concludes that the physical and mechanical properties of the brunt bricks produced in the Ashanti Region of Ghana are of acceptable quality. A recommendation is made to the manufactures to put in place proper quality control measures to improve some of the physical properties such as size variation and cracking defects of the burnt bricks.

For producing a woven fabric, sizing is one of the important steps to increase the efficiency of weaving productions. Various sizing agents such as starch, carboxymethyl cellulose (CMC), wax, emulsifier, and polyvinyl alcohol (PVA) are frequently used in the textile industry. The aim of this study is to evaluate the sizing parameters of cotton using the modified sizing agent and the frequently used sizing agent in the industry. For modification of sizing agent, various sizing chemicals are mixed together by our own recipes. Then modified sizing agents are applied to the cotton fabric along with frequently used sizing recipes. After sizing, all treated yarn and fabrics are subjected to evaluate the performance of sizing parameters and the modified sizing agent shows tenacity (20.35–21.58 cN/Tex), elongation (18.50–10.78%), initial modulus (475–486 cN/Tex), yarn hairiness reduction (95.55–95.91%), yarn unevenness (0.10–0.35 CV%), abrasion resistance (13,990 times), weight loss during abrasion (0.05–0.07%), breaking force (900–1000 F/cN), extension during maximum load (3.4–4.15 mm), and thread breakage during weaving (2.7–3.1 CMPX). The result indicated that the modified sizing agent has an acceptable range of sizing parameters and even in some cases the performances are higher than the frequently used sizing agent. The recipe of modified sizing agent contains EKACELL DT-250, EKAVIOL BEZ and EKAWAX chemicals. The most important thing that the modified sizing agent reduces the chemical consumption as well as makes cost-effectiveness of weaving production. Which is definitely be economically sustainable development in the textile industry.

On the basis of a direct current magnetron, a technology has been developed for producing nanoscale-oriented nanorods from zinc oxide on an acrylic polymer. The technology makes it possible to achieve different filling of the surface with zinc oxide nanorods. The nanorods is partially fused into the polymer; the cross section of the nanorods is rather close to an elongated ellipse. It is shown that, with intense abrasion, no delamination of the nanorods from the acrylic polymer is observed. The zinc oxide nanorods abrades together with the acrylic polymer. Zinc oxide nanorods luminesces with the wavelength most preferable for the process of photosynthesis in higher plants. It was shown that plants grown under the obtained material grow faster and gain biomass faster than the control group. In addition, it was found that on surfaces containing zinc oxide nanorods, a more intense formation of such reactive oxygen species as hydrogen peroxide and hydroxyl radical is observed. Intensive formation of long-lived, active forms of the protein is observed on the zinc oxide coating. The formation of 8-oxoguanine in DNA in vitro on a zinc oxide coating was shown using ELISA method. It was found that the multiplication of microorganisms on the developed material is significantly hampered. At the same time, eukaryotic cells of animals grow and develop without hindrance. Thus, the material we have obtained can be used in photonics (photoconversion material for greenhouses, housings for LEDs), and it is also an affordable and non-toxic nanomaterial for creating antibacterial coatings.

As a rubber annular coat of rim wheels, tyres are inevitable parts of all vehicles in modern times. As to their composition, however, they represent a risk for the environment. During the use of tyres, tyre tread patterns become abraded, which results in its gradual wear and necessary re- placement. These micro and nano particles are then gradually extracted into the environment, namely soils and waters. Our research study was focused on the assessment of subchronical phytotoxicity (pot trial with a mixture of substrate and predetermined ratio of abrasion products lasting 28 days) and biological tests (testing phytotoxicity of leaches with predetermined ratio of abrasion products on Petri dishes). The biological tests were comprised two plant species—seeds of white mustard (Sinapis alba L.) and garden cress (Lepidium sativum L.). In the mixtures of substrate with determined shares of abrasion products (5%, 25%, 50% and 75%), respiration of CO2 was also established by means of soil microbial respiration (Solvita CO2-Burst). Substrates with 5% and 25% abrasion proportions showed increased biological activity as well as increased CO2-C emissions. The increasing share of abrasion products resulted in decreasing biological activity and decreasing CO2-C emissions. The results of subchronical phytotoxicity ranged from 62% to 94% with values below 90% indicating substrate phytotoxicity. The results of biological tests focused on the phytotoxicity of tested samples exhibiting values from 35% to 70% with respect to the germination index with values below 66% indicating the phytotoxicity of tyre abrasion products.

Intrinsic self-healing materials have received significant attention due to the characteristic recovery after damage properties through reversible dynamic covalent and non-covalent interactions. Furthermore, functional recovery with reliable mechanical properties are highly keen as protective coatings, specifically for devices and sensors vulnerable to abrasion in severe environments. Here, we present a functional hierarchical nanostructure capable of multiple micro-sized healings, with enhanced mechanical hardness due to the incorporation of graphene oxide (rGO) nanoplatelets. A self-healing multilayered nanocomposite formed by poly(ethylene imine) (PEI) and poly(acrylic acid) (PAA) was easily assembled by the layer-by-layer (LbL) technique. The addition of the rGO nanoplatelets in the LbL nanostructure resulted in a 13-fold increase in hardness (0.4 ± 0.1 GPa) when compared to the (PEI/PAA) architecture (0.03 ± 0.01 GPa). In addition, the nanocomposite presents an enhanced insulating electrical behavior (∼ 4.10−8 S/cm) despite the addition of the rGO nanoplatelets. Raman and Zeta Potential analysis indicated a possible wrapping of the rGOs by PEI, justifying the observed insulating electrical characteristics. The nanocomposite presents good hydrophobicity with a water contact angle of 136°, interesting to extend the lifetime and protect underlying layers from humidity, degradation, and encrustation. Therefore, we propose an attractive hydrophobic, electrically insulating, and mechanically resistant multifunctional coating for high-performance electronic interfaces from minor cuts and abrasions, dispensing maintainer intervention.

Wood is increasingly used in construction for the benefits it brings to occupants and for its ecological aspect. Indoor wood products are frequently subject to mechanical aggressions, their abrasion and scratch resistance thus need to be improved. The coating system ensures the wood surface protection, which is, for wood flooring, a multilayer acrylate UV-curable 100% solid system. To increase the service life of wood flooring, a new property is studied: self-healing. The objective of this study is to observe the impact of monomer structure on self-healing efficiency and the effect of self-healing parameters. A previous formulation was developed using hydrogen bond technology to generate the self-healing property. In this paper, the assessment of the formulation and the self-healing parameters’ impact on self-healing efficiency as well as the physicochemical properties are presented. The composition of the monomer part in the formulations was varied, and the effect on the conversion yield (measured by FT-IR), on the Tg and crosslinking density (measured by DMA) and on mechanical resistance (evaluated via hardness pendulum, indentation, and reverse impact) was analyzed. The self-healing efficiency of the coatings was determined by gloss and scratch depth measurements (under constant and progressive load). It was proven that monomers with three acrylate functions bring too much crosslinking, which inhibits the chain mobility necessary to observe self-healing. The presence of the AHPMA monomer in the formulation permits considerably increasing the crosslinking density (CLD) while keeping good self-healing efficiency. It was also observed that the self-healing behavior of the coatings is different according to the damage caused. Indeed, the self-healing results after abrasion and after scratch (under constant or progressive load) are different. In conclusion, it is possible to increase CLD while keeping self-healing behavior until a certain limit and with a linear monomer structure to avoid steric hindrance. Moreover, the selection of the best coatings (the one with the highest self-healing) depends on the damage.

A high-carbon, high-silicon steel (1.21 wt% C, 2.56 wt% Mn, 1.59 wt% Si) was subjected to quenching from 900 and 1000 °C, resulting in microstructures containing 60 and 94% of retained austenite, respectively. Subsequent abrasive wear tests of quenched samples were performed using two-body abrasion and three-body abrasion testing machines. Investigations on worn surface and subsurface were carried out using SEM, XRD, and microhardness measurement. It was found that the highest microhardness of worn surface (about 1400 HV0.05) was achieved on samples quenched from 900 °C after three-body abrasion. Microhardness of samples after two-body abrasion was noticeably smaller. with a maximum of about 1200 HV0.05. This difference correlates with microstructure investigations along with XRD results. Three-body abrasion has produced a significantly deeper deformed layer, corresponding diffractograms show bigger values of the full width at half maximum parameter (FWHM) for both α and γ alone standing peaks. The obtained results are discussed in the light of possible differences in abrasive wear conditions and differing stability of retained austenite after quenching from different temperatures. It is shown that a structure of metastable austenite may be used as a detector for wear conditions, as the sensitivity of such austenite to phase transformation strongly depends on wear conditions, and even small changes in the latter lead to significant differences in the properties of the worn surface.

In Brazil, ceramic blocks have a significant share of the masonry construction market. Thus, an experimental testing program was devised to determine the physical and mechanical properties of ceramic blocks from different regions of Brazil. The experimental program included blocks from five Brazilian states and ten different producers, and the properties studied were absorption, material density, efflorescence, abrasion, compressive strength, and resistance towet-dry cycles. The purpose of determining these material properties is to set guidelines to standardize the performance of same-geometry blocks. The material density test method and the wet- and dry cycle test method are being proposed as new tests and are not usually specified in international codes. The objective of the wet and dry cycle test is to determine a durability parameter for blocks that are not subjected to freeze-thaw cycles. The analysis of the results identified important relationship between these properties. Keywords: masonry, clay, ceramic blocks, test in blocks.

The need to develop sustainable concrete in the civil infrastructure industry increases day by day, resulting in new eco-friendly materials such as geopolymer concrete. Geopolymer concrete is one of the eminent alternatives to conventional concrete for sustainable development by reducing the carbon footprint. Ternary blend geopolymer concrete (TGPC) is a sustainable and environmentally friendly concrete produced with three different source materials to form a binder. The main advantage of TGPC is that it possesses densely packed particles of different shapes and sizes, which results in improved properties. This paper deals with the experimental investigations to evaluate the durability properties of plain and hybrid fibre reinforced TGPC. The durability of concrete is defined as the ability to withstand a safe level of serviceability and different environmental exposure conditions without any significant repair and rehabilitation throughout the service life. Conventional concrete is vulnerable to cracking due to its low tensile and durability properties. The TGPC considered in this work consists of fly ash, GGBS and metakaolin as source materials, selected mainly based on the material’s silica and alumina content, shape, size, and availability. The grade of concrete considered was M55. The main variables considered in this study were the proportions of crimped steel fibres (Vf), viz., 0.5% and 1% and proportions of polypropylene fibres (Vp)viz., 0.1%, 0.15%, 0.20% and 0.25%. The durability properties like water absorption, sorptivity, resistance to marine attack, acid attack, sulphate attack, and abrasion were studied in this investigation. The experimental test results were compared with the requirements provided in the standard/literature and found to be well within limits. The study also indicates that the inclusion of fibres in a hybrid form significantly improves the durability parameters of TGPC. The TGPC with 1% steel fibre and 0.15% polypropylene fibre performs better than the other combination of fibres considered in this experimental investigation.

This article presents the results of tests on the resistance of new textile signal lines to bending and abrasion. The textile signal lines are one of the most important parts of the electronic system incorporated into modern smart garments. The main application of the lines presented in this article is the transmission of digital signals or high-frequency analogue signals. The tested lines were made of fabrics with sewn paths made of electro-conductive fabric. The construction of a measuring stand for testing the electric properties of textile transmission lines is shown. This article presents the effects of bending and abrasion on the resistance of electro-conductive strips, which are one of the elements of textile signal lines. The article also presents the effects of bending and abrasion on the characteristic impedance of constructed textile signal lines. Statistical analysis of the obtained results is also presented.

[Abstract] This work proposes a green material for artificial reefs to be placed in Galicia (northwest Spain) taking into account the principles of circular economy and sustainability of the ecosystem. New concrete formulations for marine applications, based on cement and/or sand replacement by mussel shells, are analyzed in terms of resistance to abrasion. The interest lies in the importance of the canning industry of Galicia, which generates important quantities of shell residues with negative environmental consequences. Currently, the tests to determine the abrasion erosion resistance of concrete on hydraulic structures involve large and complex devices. According to this, an experimental test has been proposed to estimate and compare the wear resistance of these concretes and, consequently, to analyze the environmental performance of these structures. First, a numerical analysis validated with experimental data was conducted to design the test. Subsequently, experimental tests were performed using a slurry tank in which samples with conventional cement and sand were partially replaced by mussel shell. The abrasive erosion effect of concrete components was analyzed by monitoring the mass loss. It shows an asymptotic trend with respect to time that has been modeled by Generalized Additive Model (GAM) and nonlinear regression models. The results were compared to concrete containing only conventional cement and sand. Replacing sand and/or cement by different proportions of mussel shells has not significantly reduced the resistance of concrete against erosive degradation, except for the case where a high amount of sand (20 wt.%) is replaced. Its resistance against the erosive abrasion is increased, losing between 0.1072 and 0.0310 wt.% lower than common concrete. In all the remaining cases (replacements of the 5–10 wt.% of sand and cement), the effect of mussel replacement on erosive degradation is not significant. These results encourage the use of mussel shells in the composition of concrete, taking into account that we obtain the same degradation properties, even more so considering an important residue in the canning industry (and part of the seabed) that can be valorized. This research was funded by Xunta de Galicia through the project CN-10MMA003CT. This study was also funded through the collaboration agreement between Xunta de Galicia (Convenio de colaboración entre a Xunta de Galicia, a Universidade da Coruña e a Fundación da Universidade da Coruña para dar continuidade ao Proxecto de investigación de arrecife artificial—PROARR), Universidade da Coruña and the Universidade da Coruña Foundation (FUAC) to give continuity to the previous project. The research of Javier Tarrío-Saavedra has been supported by MINECO grant MTM2017-82724-R, Ministerio de Ciencia e Innovación grant PID2020-113578RB-100, and by the Xunta de Galicia (Grupos de Referencia Competitiva ED431C-2020-14 and Centro de Investigación del Sistema universitario de Galicia ED431G2019/01), all of them through the ERDF Xunta de Galicia; 10MMA003CT Xunta de Galicia; ED431C-2020-14 Xunta de Galicia; ED431G2019/01

The application of asphalt hot mix recycling is one challenge in sustainable road pavement research. In addition to the vast amount of research on the performance of recycled asphalt–concrete, the research on the frictional resistance of recycled hot mix asphalt is still limited. The effects of aged asphalt and aged aggregates on the skid resistance of recycled hot mix asphalt were investigated in this research. The aged asphalt and aged aggregates were carefully extracted from the field-reclaimed asphalt pavement, and the engineering and mechanical properties of aged and virgin aggregates were measured. The degradation of recycled hot mix asphalt was simulated using an accelerated polishing machine to mimic road surface abrasion. Accordingly, the initial and final skid resistances of the recycled hot mix asphalt were determined and correlated with the properties of the aged asphalt and aggregates. The initial skid resistance of recycled hot mix asphalt decreased with reductions in penetration and ductility of the blended asphalt. However, the changes in the blended asphalt properties contributed only small variations to the final skid resistances of the recycled hot mix asphalt. The gradations of recycled hot mix asphalt correlated only with the final skid resistances. The aggregate gradations controlled the characteristics of the final skid resistance since the covered binder was partially polished off from the road surface at this stage.

The pollution caused by microplastics around the world is an increasingly significant issue that has to be tackled with different methods and technologies. Here, we report a straightforward and rapid process combining electrodeposition and electrophoresis to produce a durable superhydrophobic coating on an aluminum substrate (UNS A91070) that has a static contact angle (153°), sliding angle (1°), and contact angle hysteresis (1°). Field emission scanning electron microscopy and high-resolution transmission electron microscopy showed the presence of a hierarchical structure with nanolayers that were 70 nm thick. The chemical composition was also analyzed using attenuated total reflectance-Fourier transform infrared spectroscopy and high-resolution X-ray photoelectron spectroscopy, which revealed that the hierarchical structure was composed of zinc laurate (Zn(C11H20COO)2) that decreased the surface free energy of the system. Moreover, the coating showed high durability against abrasion caused by the P1200 SiC paper due to the presence of TiO2 particles in the upper layers as well as the homogeneous chemical composition of the hierarchical structure. Finally, taking advantage of the superoleophilic properties of superhydrophobic surfaces, the ability of the coating to remove high-density polyethylene microplastics from water was studied.

The use of Recycled concrete aggregate (RCA) obtained from construction and demolition waste not only reduces the need for virgin aggregates but also solves the problems associated with the disposal of construction and demolition (C&D) waste. Despite being a promising prospect, field utilization of RCA in bituminous mixes is limited due to the problems like lower strength and higher moisture susceptibility. To solve these issues present study aims at examining the effect of lime filler on RCA incorporated bituminous mixes. In the present study, RCA was obtained by mechanically treating C&D waste in a Los Angeles abrasion machine. Bituminous mixes were prepared by using 10%–50% of RCA. Additionally, 2% lime was added to the RCA incorporated mixes, and the parameter like optimum bitumen content, Marshall stability, Marshall quotient, Indirect tensile strength, Retained Marshall stability and Tensile strength Ratio were compared with the control mix to examine the effect of RCA and lime on mix properties. The inclusion of RCA was found to adversely affecting the properties of the mix whereas the inclusion of lime improved the properties. To provide a clear understanding of the environmental and economic benefits of utilizing RCA in bituminous mixes, economic and environmental assessment was also done. Based on different test results and analysis it was concluded that with the use of lime fillers it is possible to produce economical and environmentally friendly RCA incorporated bituminous mixes having properties comparable/better than conventional hot mix asphalt (HMA).

This study depicts the investigations of the effect of composition of aromatic polyester polyol produced from terephthalic acid (TPA) and different concentrations of mono ethylene glycol (mEG) as a chain extender on the mechanical properties of polyurethane (PU) elastomer. Aromatic polyester polyols are prepared via the poly-esterification of adipic acid, terephthalic acid, catalyst, and mono ethylene glycol, while a polyurethane elastomer is formulated via the pre-polymerization of polyol with pure monomeric Methylene diphenyl diisocyanate (MDI.) Mechanical properties of polyurethane elastomers are examined, such as hardness via shore A hardness, apparent density via ASTM (American Society for Testing and Materials) D1622–08, and abrasion wear resistance via a Deutches Institut fur Normung (DIN) abrasion wear resistance tester. Structural properties are investigated through Fourier-transform infrared spectroscopy (FTIR) analysis. Results reveal that the shore A hardness of the PU elastomer increases with an increasing concentration of mEG from 4g to 12g. Nevertheless, the elastomer’s density depicts a reduction with an increasing extender content. The abrasion wear resistance of polyurethane, however, increases with an increasing concentration of glycol. A structural analysis through FTIR confirms the formation of polyurethane elastomer through the characteristic peaks demonstrated.

Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a first maxillary molar was done and scanned by an intraoral scanner to make a digital model. Then, the prosthetic crown was digitally designed on the CAD software, and the STL file was milled in zirconia (CaroZiir S, Carol Zircolite Pvt. Ltd., Gujarat, India) and PEEK (BioHpp, Bredent GmbH, Senden, Germany) crowns using five-axis CNC milling machines. The wear resistance, color stability, and displacement resistance of the milled monolithic zirconia with unfilled PEEK crowns using a chewing simulator with thermocyclic aging (120,000 cycles) were compared. The antagonist wear, material wear, color stability, and displacement were evaluated and compared among the groups using the Wilcoxon–Mann–Whitney U-test. Zirconia was shown to be three times more abrasive than PEEK (p value &lt, 0.05). Zirconia had twice the wear resistance of PEEK (p value &lt, 0.05). Zirconia was more color stable than PEEK (p value &lt, 0.05). PEEK had more displacement resistance than zirconia (p value &lt, 0.05). PEEK offers minimal abrasion, better stress modulation through plastic deformation, and good color stability, which make it a promising alternative to zirconia crown.

Traffic is a significant pollution source in cities and has caused various health and environmental concerns worldwide. Therefore, an improved understanding of traffic impacts on particle concentrations and their components could help mitigate air pollution. In this study, the characteristics and sources of trace elements in PM2.5 (fine), and PM10-2.5 (coarse), were investigated in dense traffic areas in Toronto and Vancouver, Canada, from 2015–2017. At nearby urban background sites, 24-h integrated PM samples were also concurrently collected. The PM2.5 and PM10-2.5 masses, and a number of elements (i.e., Fe, Ba, Cu, Sb, Zn, Cr), showed clear increases at each near-road site, related to the traffic emissions resulting from resuspension and/or abrasion sources. The trace elements showed a clear partitioning trend between PM2.5 and PM10-2.5, thus reflecting the origin of some of these elements. The application of positive matrix factorization (PMF) to the combined fine and coarse metal data (86 total), with 24 observations at each site, was used to determine the contribution of different sources to the total metal concentrations in fine and coarse PM. Four major sources were identified by the PMF model, including two traffic non-exhaust (crustal/road dust, brake/tire wear) sources, along with regional and local industrial sources. Source apportionment indicated that the resuspended crustal/road dust factor was the dominant contributor to the total coarse-bound trace element (i.e., Fe, Ti, Ba, Cu, Zn, Sb, Cr) concentrations produced by vehicular exhaust and non-exhaust traffic-related processes that have been deposited onto the surface. The second non-exhaust factor related to brake/tire wear abrasion accounted for a considerable portion of the fine and coarse elemental (i.e., Ba, Fe, Cu, Zn, Sb) mass at both near-road sites. Regional and local industry contributed mostly to the fine elemental (i.e., S, As, Se, Cd, Pb) concentrations. Overall, the results show that non-exhaust traffic-related processes were major contributors to the various redox-active metal species (i.e., Fe, Cu) in both PM fractions. In addition, a substantial proportion of these metals in PM2.5 was water-soluble, which is an important contributor to the formation of reactive oxygen species and, thus, may lead to oxidative damage to cells in the human body. It appears that controlling traffic non-exhaust-related metals emissions, in the absence of significant point sources in the area, could have a pronounced effect on the redox activity of PM, with broad implications for the protection of public health.

In this study, the compressive strength and water contact angle of mortar specimens prepared by mixing two types of water repellent with ordinary Portland cement (OPC) and rapid-hardening cement mortar were measured before and after surface abrasion. In addition, the hydration products and chemical bonding of cement mortar with the repellents were examined using X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the performance of these cement mortar mixtures as repair materials. We found that the fast-hardening cement mortar mixture containing the oligomer water repellent showed the best performance with a high compressive strength and large water contact angle. With the oligomer water repellent, the rapid-hardening cement mortar mixture showed contact angles of 131° and 126° even after a 2 mm abrasion, thereby confirming that the water repellent secured hydrophobicity through strong bonding with the entire cement mortar as well as its surface. The compressive strengths were found to be 34.5 MPa at 3 h and 54.8 MPa at 28 days, confirming that hydration occurred well despite the addition of water repellent.

Recycling waste glass for developing cementitious and geopolymeric concretes as sustainable construction materials have recently attracted increasing attentions for the construction industry. There are many previous studies on the effects of waste glass used as powder, sand or cullet based on the various sizes on the fresh and mechanical properties of concrete. However, there are few studies conducted on the durability performance of waste glass concrete. In this paper, in addition to a brief review on the fresh and mechanical properties and microstructure, the durability performance of concrete with waste glass is comprehensively reviewed under various environmental actions, including chemical attacks, chloride transport, high temperature, freeze-thaw cycles, carbonation, efflorescence, abrasion, alkali-silica reaction (ASR), and practical applications. It was found that the type, size and replacement ratio of waste glass significantly affect concrete durability. Compared to the glass cullet, the fine glass powder can usually improve the long-term durability, because the enhanced pozzolanic reactivity can reduce the ASR expansion due to the densified microstructure and reduced porosity. On the other hand, other factors such as mineral additives, mixing and curing methods also potentially affect the durability. Finally, some research perspectives and challenges of concrete with recycled waste glass are also presented and discussed. Considering the potential applications of waste glass concrete, this comprehensive review will provide an insight into an in-depth understanding of the production and performance for promising application.

Natural rubber is of significant economic importance owing to its excellent resilience, elasticity, abrasion and impact resistance. Despite that, natural rubber has been identified with some drawbacks such as low modulus and strength and therefore opens up the opportunity for adding a reinforcing agent. Apart from the conventional fillers such as silica, carbon black and lignocellulosic fibers, nanocellulose is also one of the ideal candidates. Nanocellulose is a promising filler with many excellent properties such as renewability, biocompatibility, non-toxicity, reactive surface, low density, high specific surface area, high tensile and elastic modulus. However, it has some limitations in hydrophobicity, solubility and compatibility and therefore it is very difficult to achieve good dispersion and interfacial properties with the natural rubber matrix. Surface modification is often carried out to enhance the interfacial compatibilities between nanocellulose and natural rubber and to alleviate difficulties in dispersing them in polar solvents or polymers. This paper aims to highlight the different surface modification methods employed by several researchers in modifying nanocellulose and its reinforcement effects in the natural rubber matrix. The mechanism of the different surface medication methods has been discussed. The review also lists out the conventional filler that had been used as reinforcing agent for natural rubber. The challenges and future prospective has also been concluded in the last part of this review.

Coating materials with special surface wettability are widely applied in marine paint systems used in the naval industry to reduce the corrosion and viscous drag of seawater. However, traditional coatings are inefficient and limited, either by poor durability or insufficient anti-drag capacity. Here, inspired by the diving bell spider, a bionic superhydrophobic coating with multiscale hierarchical architecture was successfully prepared on the surface of aluminium alloy. It possesses excellent mechanical abrasion durability, chemical durability, and low adhesion. Remarkably, the water contact angles could remain over 150.9° after more than 15 abrasion cycles or strong acid/alkali conditions. In addition, the impacting water droplet lifted off the surface of bionic superhydrophobic aluminium alloy (BSAA) within 13 ms, illustrating an excellent low adhesion property. In fact, when the BSAA is immersed in water, it could absorb bubbles and form a gas membrane. The existence of the gas membrane could prevent water and anaerobic organisms from contacting and even corroding the BSAA. Meanwhile, the gas membrane acts as a lubricant and significantly deceases friction at the solid–liquid interface, reducing the drag for BSAA. The BSAA proposed in this work has broad application prospects, such as medical devices, microfluidic chips, gas separation and collection in water.