Polishing Resistance Research Articles

In Situ Analysis of the Effect of Ultrasonic Cavitation on Electrochemical Polishing of Additively Manufactured Metal Surfaces

Abstract The effects of a hybrid process that combines ultrasonic cavitation and electrochemical polishing on the electrochemical behavior and the resulting surface characteristics of additively manufactured 316-L stainless steel were investigated. In situ potentiodynamic scans and electrochemical impedance spectroscopy (EIS) were conducted to gain a fundamental understanding of the effect of ultrasonic cavitation on the electrochemical processes involved, considering the influence of electrolyte temperature at 60 and 70 °C. The potentiodynamic scans revealed that increasing the ultrasonic excitation amplitude from 20 to 80 µm at 20 µm intervals and temperature from 60 to 70 °C led to reduced polishing resistance, and elevated passivation current density at equivalent applied potentials, thus leading to an increased polishing rate. These findings are attributed to intensified cavitation near the material surface, which promoted anodic dissolution reactions and accelerated the polishing rate. In situ EIS measurements provided valuable information on the charge transfer resistance and double-layer capacitance and their influence on the hybrid process. Specifically, higher ultrasonic amplitudes and elevated temperatures contributed to enhanced electrical double-layer formation and ion adsorption, resulting in a faster rate of polishing, indicating the efficacy of the hybrid process. These findings enhance our understanding of the complex interactions between ultrasonic cavitation and electrochemical dissolution processes that occur during ultrasonic cavitation-assisted electrochemical polishing. The research provides valuable insights for optimizing the process and its potential application in the post-processing of metal additive manufactured parts.

A Cleaner Pavement Preventive Maintenance Approach: Performance and Emission Impact Analysis of Slurry Surfacing Containing Electric Arc Furnace Slag

Incorporating Electric Arc Furnace Slag (EAFS) into construction materials such as hot-mix asphalt and Portland cement concrete has shown increasing wear and polishing resistance while reducing solid waste and mitigating the carbon footprint of construction engineering. Pavement surface treatment is one of the most used pavement preservation approaches. The slurry surfacing (SS) technique provides the most hot-mix asphalt-like surface texture among the surface treatment techniques. This study aimed to investigate the feasibility of using EAFS for SS by incorporating various amounts of EAFS and then analyzing the treatment's performance and the resulting carbon footprint reduction. Performance tests of SS, including the wet track abrasion test and loaded wheel test, were performed to evaluate SS's abrasion and deformation resistance. Aggregate packing degree and bonding strength based on the surface charge were also considered to understand the mechanism affecting the performance. The corresponding reduction in carbon footprint is then analyzed using the tiered hybrid life cycle assessment method to understand further the benefits of using EAFS in SS. The results revealed that mixtures incorporating EAFS could be carefully designed to perform better by increasing the packing degree and bonding strength. Also, adding EAFS into SS increased abrasion resistance by up to 18.2%, rutting resistance by up to 72.8%, and reduced the carbon footprint by up to 39.6%.

Effect of Blending Steel Slag Aggregates on the Polishing Resistance of Asphalt Pavement Surface

Abstract The objective of the work presented in this paper is to investigate the effect of blending steel slag aggregates (SSAs) with natural aggregates (NAs) on the polishing resistance of the asphalt pavement surface. The investigation involved polishing five sources of NA (granite [3] and amphibolite [2]), one source of SSA, and three SSA blends (mass proportions: 20/80, 50/50 and 80/20). The polishing trends were captured by measuring the British Pendulum Number (BPN) at hourly intervals for 9 h. The laboratory polishing trends suggested that the SSA blending resulted in improved polishing resistance. Based on the polishing trends observed in the laboratory, a suitable mathematical form was selected to model the aggregate polishing. The transfer functions (or shift factors) for the field model were derived by comparing the laboratory polishing with the field polishing trends. The field polishing trend was captured by BPN collected over 3 years at selected locations on two pavements with stone matrix asphalt (SMA) surfaces course mix that were produced with the same aggregates tested in the laboratory. The prediction results from the field BPN deterioration models showed good consistency between field observations and model response values. Using the derived shift factors and laboratory BPN deterioration model parameters, field models for BPN deterioration were developed based on which life prediction of pavement with SMA surface can be made. Field BPN deterioration models suggest that blending of SSA prolongs the residual life up to 10 % depending on the blend proportion and threshold BPN criteria.

Predicting the Friction Coefficient of High-Friction Surface Treatment Application Aggregates Using the Aggregates’ Characteristics

Providing sufficient pavement surface friction (i.e., skid resistance) between vehicle tires and pavement surface throughout the pavement service life is considered to be one of the main objectives of highway design. Moreover, vehicle safety, the amount of consumed fuel, and the wearing rate of vehicle tires generally are influenced by pavement surface friction. In this study, a comprehensive experimental testing program was conducted on different aggregate sources, including calcined bauxite and five alternative local sources, to assess their friction characteristics. The testing program included a British pendulum tester (BPT) and a dynamic friction tester (DFT), which were used to evaluate the friction characteristics of the proposed aggregates, along with basic and durability properties tests. The aggregate imaging measurement system (AIMS) technique was applied to evaluate the aggregate characteristics due to Micro-Deval degradation. This study provides two empirical models for the friction characteristics of high-friction surface treatment (HFST)-application aggregates based on the experimental results. The first model correlates the friction coefficient at 20 km/h (DFC20) with the British pendulum number (BPN). The second model expresses DFC20 as a function of polishing resistance of aggregates, which is represented by the initial and terminal aggregate texture and angularity values measured using the AIMS device with an overall coefficient of determination (R2) of 0.949. The aggregate characteristics (i.e., particle angularity and surface texture) align well with the microtexture characteristics of the investigated sources.

Effect of morphology characteristics on the polishing resistance of coarse aggregates on asphalt pavement

Skid resistance performance of asphalt pavement is an important factor affecting the traffic safety. The long-term skid resistance performance of asphalt pavement depends on abrasion and polish resistance of aggregates. However, the mechanical properties and surface morphological characteristics of aggregates not only affect the road bearing capacity, but also impact the long-term abrasion and polish resistance of asphalt pavement. In this study, the mechanical properties of limestone, basalt, granite and 88 # calcined bauxite were investigated. The macro morphology characteristic parameters (MACP) of coarse aggregates were obtained by Image Pro Plus (IPP) software analysis with strong applicability, and the distribution models and characteristics were further analyzed. In order to present quantitatively the dynamic change process of the macro and micro morphology characteristics of coarse aggregates with the polished stone value (PSV) during the polishing process, a long-term polishing test was carried out on the coarse aggregates. The MACP and micro morphology characteristic parameters (MICP) of coarse aggregates were obtained by the IPP analysis and three-dimensional laser microscope. The grey relation entropy analysis method was used to analyze the correlation degree between morphological characteristic parameters and PSV. The results show that the contents of corundum and mullite in 88 # calcined bauxite are 85.2% and 14.8% severally. Corundum and mullite have the highest Mohs hardness, 9 and 6 respectively. The IPP analysis is suitable for quickly obtaining the MACP of coarse aggregates, and the MACP distribution of four kinds of coarse aggregates satisfies well normal distribution. In addition, in the process of PSV attenuation, the grey entropy correlation coefficients between PSV and fractal dimension, Rq are the highest, 0.9037 and 0.8882 respectively. The fractal dimension of MACP and Rq of MICP are selected as the main various indexes. Meanwhile, the average correlation coefficients of fractal dimension, Rq and PSV are 0.9589 and 0.9809 separately. Therefore, the fractal dimension and Rq are proposed to evaluate the long-term polishing resistance performance of coarse aggregates, and to provide useful references for the long-term skid resistance modeling of durable asphalt pavement.

Study on the Skid Resistance Deterioration Behavior of the SMA Pavement

The skid resistance of asphalt pavement is of great importance to the driving safety, but deterioration of pavement skid resistance is inevitable owing to the coupling effect of traffic loading and climate conditions. The existing prediction models of skid resistance were mainly established based on the laboratory accelerated polishing tests (for instance Polished Stone Value, PSV), and these models can only consider the influence of a single factor; they fail to reflect the coupling effect of different factors under the real service condition. For the purpose of investigating the influences of seasonal variation, and aggregate type on the skid resistance of asphalt pavement, the skid resistance of three test tracks were continuously measured for 48 months through five different test methods. The results show that different test methods exhibit significant inconsistency. The aggregate type is the internal factor that determines the long-term skid resistance performance of pavement. The skid resistances of the selected test tracks were ranked as greywacke pavement > diabase pavement > rhyolite pavement. This is in well agreement with the ranking of aggregate polishing resistance obtained from the laboratory Wehner/Schulze (W/S) test. This indicates that the W/S test is effective in distinguishing the aggregates that used in pavement construction. It is also found that the skid resistance of asphalt pavement shows significant fluctuation with respect to seasonal variation. The skid resistance is generally high in autumn and low in summer. Therefore, it is suggested to use the low measurement value of skid resistance in summer as the lower limit for the evaluation and prediction of the skid resistance performance of asphalt pavement.

Viability of Using High Amounts of Steel Slag Aggregates to Improve the Circularity and Performance of Asphalt Mixtures

Steel slag is a byproduct generated as waste during the steelmaking process and can be considered a cost-effective and environmentally acceptable alternative to replace natural aggregates. Using steel slag aggregates (SSA) to produce asphalt mixtures promotes sustainability and circular economy principles by using an industrial byproduct as a raw material. Thus, this work mainly aims to design more sustainable asphalt mixtures with high amounts of SSA that fit the circular economy expectations. This work developed two asphalt mixtures with SSA for surface (AC 14 surf) and binder/base (AC 20 bin/base) courses. Initially, the excellent wearing and polishing resistance of SSA and their good affinity with bitumen demonstrated the potential of this byproduct to be used in asphalt mixtures. Then, when analyzing the influence of using two different SSA incorporation rates (50% and a percentage close to 100%) in both asphalt mixtures, it was concluded that the use of SSA should be limited to 75% to avoid excessive air void contents and durability problems. The importance of considering the different particle densities of SSA and natural aggregates was highlighted during the mix design by defining a relationship between an effective and equivalent binder content. Finally, the mechanical performance of AC 14 and AC 20 with 75% SSA incorporation was compared to identical conventional mixtures produced with natural granite aggregates. The results obtained showed that the asphalt mixtures with 75% SSA have some workability problems due to the rough and porous surface of SSA. However, they present an excellent water sensitivity and permanent deformation resistance, surpassing the performance of the conventional asphalt mixtures.

Effect of coarse aggregate mineralogy on micro-texture deterioration and polished stone value

The objective of the study presented in the paper is to identify the mineralogical parameters that influence both micro-texture deterioration and Polished Stone Value (PSV), which are the two most important properties of the aggregates that control the pavement skid resistance. The study was carried out on fourteen sources of aggregates which belong to either igneous or metamorphic rock category, the two most commonly used aggregate categories for surface course mixtures in India. PSV of aggregates was determined as per BS EN 1097-8: 2009. To investigate the progressive extent of polishing, the British Pendulum Number (BPN) of the aggregate was determined after every hour of polishing. Simultaneously, the mineralogical parameters were also obtained based on the microscopic observations of the thin sections of the aggregates. From accelerated polishing tests, it was observed that igneous aggregates, especially granites, were found to have relatively high PSV and good polishing resistance. Nevertheless, granite aggregates with altered minerals witnessed poor polishing resistance. Correlation analysis on the combined data for igneous and metamorphic aggregates suggested that the mineralogical parameters such as Relative Hardness (RHD) of aggregates, Differential Hardness (DH) between major minerals within the aggregate, and degree of alteration (DA) influence micro-texture deterioration rate (BPN3-BPN6). PSV showed a good correlation with RHD and DH. It was also noted that altered granite aggregates of igneous type significantly influenced the correlation. In general, it was observed that fundamental mineralogical parameters can better predict BPN3-BPN6 than PSV.

The influence of crushing processes and mineralogy of aggregates on their shape properties and susceptibility to degradation

The selection of appropriate aggregates should consider important factors such as mineralogical characteristics and crushing processes. This paper aims to investigate the relations between aggregates sources, crushing processes, shape, and resistance to degradation. Therefore, different materials were compared in terms of mineralogy and shape. Each material was also submitted to degradation tests to evaluate breakage, abrasion, and polishing resistance. The heterogeneity of gneissic aggregates led to increase on angularity of coarse particles as their sizes reduced and also to varying behavior due to wearing. Cone crushers led to higher sphericity and lower angularity, thus being suitable for Portland cement concrete.

Material design and performance analysis of the anti-ice and antiskid wear layer on pavement

A design method for an anti-ice and antiskid wear layer on pavement is presented in this paper. A kind of bonding material with excellent properties has been developed that can maintain a good bonding ability in high and low temperature environments and has good UV aging resistance. Porous high-strength shale aggregates are used to replace portions of stone, and the functional characteristics of the ice inhibition of the wear layer are realized by soaking in saturated salt water. The results show that after adding ceramsite, the freezing point of pavement can be reduced by approximately 5 °C at most and the ice melting rate can be increased by approximately 30%. After continuous soaking for ten days, salt can still be precipitated from the aggregate, which can inhibit the formation of an ice film to a certain extent. As the proportion of ceramsite increases, the polishing resistance of the pavement increases. Under conditions of flooding and freezing, the BPN of the aggregate mixed with ceramsite is approximately 50% higher than that of andesite aggregate. The wear layer can provide a good anti-ice and antiskid performance, which is helpful for traffic safety under wintry conditions.

Improving the polishing resistance of cement mortar by using recycled ceramic

Recycling of construction and demolition (C&D) waste is one of the most effective ways to develop sustainable pavements. In this study, the feasibility of using ceramic waste as an alternative source for fine aggregate to improve the polishing resistance of cement mortar is investigated. The recycled fine aggregates used in this study originate from sanitary ceramic waste; the physical and chemical properties of the Recycled Ceramic Aggregates (RCA) were determined. The optimal RCA content in the mortar was determined based on the mechanical strength of the resulting composite. The polishing resistance of coarse and fine RCA was characterized with the Polished Stone Value (PSV) test and the Wehner/Schulze (W/S) test, respectively. The test results indicate that the polishing resistance of RCA is significantly better than that of commonly used mineral aggregate. Lastly, the self-developed Aachen Polishing Machine (APM) was applied to validate the improvement of RCA on the polishing resistance of cement mortar under realistic loading conditions. The cement mortar containing RCA exhibits a better long-term polishing resistance than the traditional mortar. The results from this study provide insights into the application of RCA in concrete pavements and the improvement of material properties.

Electrical resistivity and mechanical properties of nitrogen-containing diamondlike carbon/tungsten and nitrogen-containing diamondlike carbon/tungsten carbide multilayer films prepared under low substrate temperature

Nitrogen-containing diamondlike carbon (N-DLC) films are excellent surface protection films with high wear resistance and low electrical resistivity. In this paper, N-DLC/tungsten (W) and N-DLC/tungsten carbide (WC) multilayer films with low-electrical-resistance layers formed between N-DLC layers are presented. W or WC layers were formed as a low-electrical-resistance layer using unbalanced magnetron sputtering methods at a low substrate temperature. N-DLC layers were fabricated by the T-shape filtered arc deposition method. The N-DLC/WC multilayer films showed higher polishing resistance compared with the N-DLC single-layer films, and the electrical resistivity of the multilayer films was about half compared with single-layer films. The high polishing resistance of the multilayer films was considered to be due to the WC layers acting as a hard layer and the N-DLC layers acting as a cushion layer to absorb the film load.

Field performance evaluation of high friction surface treatments (HFST) in Oklahoma

The high friction surface treatment (HFST) is an effective countermeasure to roadway departure crashes. The field performance of the HFST system was evaluated from seven field monitoring trials on six HFST sites in Oklahoma from 2015 to 2017. HFST sections have statistically significant higher pavement friction and macrotexture in contrast to the adjacent untreated pavements. Meanwhile, distresses including patching, reflective cracking, raveling, and delamination have been observed on these HFST sites. The number of property damage crashes and injured crashes before and after the HFST installation are queried from the Oklahoma safety database. The HFST results in 29% to 100% reductions of annual property damage crashes and 100% reduction of annual injured crashes. The benefit-cost ratios of the HFST sites range from 6.9 to 27.9. In addition, HFST sites constructed with bauxite show higher friction numbers and better polishing resistance performance than sites using the local mine chat aggregates.

Wear-resistive and electrically conductive nitrogen-containing DLC film consisting of ultra-thin multilayers prepared by using filtered arc deposition

Nitrogen-containing diamond-like carbon (N-DLC) multilayer films approximately 500 nm thick were fabricated on tungsten carbide substrates as surface protective films with high wear-resistive and conductive properties. Each layer thickness of the N-DLC multilayer films was approximately 10 nm, and the films were a periodic bilayer structure consisting of hard and soft N-DLC layers. Owing to the high abrasion resistance of the hard layer and the low aggressiveness and high adhesion of the soft layer, the multilayer films showed good polishing and wear resistances compared with the hard N-DLC monolayer film, and the electrical resistivity was about half. In the case of DLC multilayer films consisting of hard N-free DLC and N-DLC films, the decrease of each layer thickness leads to the reduction of the polishing resistance. From X-ray reflectivity analysis of ultra-thin N-free DLC films, it was indicated that the film density of an ultra-thin N-free DLC film is lower than that of a thick N-free DLC film. In the DLC multilayer film with thin N-free DLC layers, it is possible that the polishing resistance of the whole DLC film reduced because the hardness the N-free DLC layer was decreased due to the low film density of each N-free DLC layer.

Flash electropolishing of TEM lamellas of irradiated tungsten

The study in the transmission electron microscopy (TEM) of the irradiation-induced microstructure of tungsten, a material promising for its applications at high temperatures in harsh radiation environments, is rendered difficult by the high level of radioactivity. To circumvent this problem, it is nowadays a routine to reduce the TEM sample size with the focused ion beam (FIB) technique. In this way, one extracts an electron transparent thin lamella that is only a few microns in size. However, FIB induces additional radiation damage in the surface layer, which has to be removed by the so-called flash polishing technique in order to detect the initial damage structure in an irradiated sample. In this study, we evaluate the technique of flash electropolishing in an aqueous solution of NaOH as a method to remove this surface damage from tungsten lamella samples. The conditions of flash electropolishing are optimized as a function of temperature, voltage, FIB grid and weld material. Anisotropic etching dependence on the crystallographic direction was evaluated, with the highest polishing resistance in the region between (5 2 1) and (1 1 0).

An evaluation method for the polishing and abrasion resistance of aggregate

The polishing resistance performance and abrasion resistance performance of aggregate affect the long-term skid resistance and durability of the pavement, but there is still a lack of a comprehensive evaluation method to evaluate the aggregate performance in all aspects. This paper presents a study to develop a comprehensive evaluation method based on the assessments of four types of common aggregates in pavement engineering. The Wehner/Schulze polishing test and Micro-Deval abrasion test are used to respectively analyse the polishing resistance performance and abrasion resistance performance of the four aggregates. A comprehensive method for evaluating aggregate properties is proposed based on a laboratory test, the slope of the linear fitting line of the test results and the distribution of the results in the coordinate plot can reflect the performance of different aggregates, thus the coordinate plot is separated into four quadrants, aggregates falling into different quadrants are evaluated as good, fair and poor, respectively, so that to provide reference for aggregate screening or aggregate blending in pavement engineering.

Development of aggregate micro-texture during polishing and correlation with skid resistance

ABSTRACTThis paper presents a laboratory study aiming to characterise the influences of aggregate micro-texture on the skid resistance under consideration of different wavelengths. To achieve this objective, 11 kinds of aggregates were used to prepare aggregate specimens. Micro-Deval (MD) and Aachen Polishing Machine (APM) were utilised to represent the changes in aggregate morphology which is caused by traffic loading. The Wehner/Schulze (W/S) test was used to measure the skid resistance. A high-resolution profilometer was utilised to collect the surface topography of the specimens. The two-dimensional power spectral density of the aggregate specimens was calculated based on the collected surface topography to investigate the differences in texture resulting from abrasion and polishing. Furthermore, the key wavelength ranges of the pavement surface texture responsible for the skid resistance is identified. The key wavelength range was then divided into four subranges; thereafter, the effect of the micro-texture on the skid resistance is investigated. Analyses show that the MD and APM affected different wavelength ranges of the texture. The most influential wavelength range for the skid resistance is found to be 32–128 µm. Mineral properties and the composition of aggregate directly affect the skid-resistant performance as well as the polishing resistance.

Polishing resistance of polymer concrete pavement using limestone aggregate

ABSTRACTThe purpose of this research was to investigate the polishing resistance of uncoated and resin-coated specimens under polishing and chemical attack. Low-quality aggregate, limestone and orthophthalic unsaturated polyester resin were the main materials. From the analysis, the macrotexture was reduced from the coarser aggregate to finer aggregate mix proportion. Resin-coated specimen was more polishing resistant than the uncoated specimen. Thickness reduction for resin-coated specimen was 1.8% after 9 h polishing, while the thickness reduction for uncoated specimen was 1.9% after 6 h polishing. In comparison with the uncoated specimen, the British pendulum number (BPN) of resin-coated specimen under dry and wet conditions was 8% higher and 16% lower, respectively. For the chemical resistant investigation, the immerging mediums used were water, sulphuric acid, sodium chloride, sodium hydroxide and used engine oil. The uncoated and resin-coated specimens were immersed into the solutions under direct immersion as well as wetting and drying for 24 weeks. Sulphuric acid and sodium hydroxide affected the BPN on both uncoated and resin-coated specimens but not for water and used engine oil, while sodium chloride only affected the BPN of the uncoated specimen.

An approach to mitigate effects of colour variation, specularity and pores on microtexture analysis of aggregates

ABSTRACTPrevious research indicated that color variation, specularity, and porosity, which are not related to surface roughness or texture of aggregate, affect the value of Texture Index (TI) determined using standard procedures associated with Aggregate Image Measurement System (AIMS). In response, a new technique called Photometric Stereo-Independent Component Analysis (PS-ICA) was developed and found to effectively mitigate color variation effect. Reduced light intensity was found to partially, but not completely, mitigate specularity effect. However, effect of pores could not be mitigated with measurements obtained from existing AIMS procedures. An extensive evaluation was conducted on a broad range of aggregates to determine whether TI values obtained before and after polishing using PS-ICA and reduced light intensity resulted in appropriate assessment of polishing resistance. For aggregates exhibiting strong specularity, it was found that specularity effect increased after initial polishing, which increased TI, thereby confounding and sometimes overwhelming the reduction in TI associated with reduced roughness. The specularity effect appeared to remain constant after initial polishing, such that further polishing resulted in a more consistent reduction in TI. For aggregates not exhibiting specularity, reduction in PS-ICA TI after initial polishing was found to be an excellent parameter to assess polishing resistance.

Evaluation of the polishing resistance characteristics of fine and coarse aggregate for asphalt pavement using Wehner/Schulze test

Traffic safety is influenced strongly by the skid resistance of pavements. Moreover, the long-term skid resistance of pavements depends mainly on the polishing resistance of the specific aggregate present on the surface. The polishing resistance is a measure which describes the roughness of aggregate after a polishing load has been induced by traffic loads. Specifications for the polishing resistance of aggregate are given only for coarse aggregate. However, given the various mixture types it is questionable if the fraction of fine aggregate (up to 55 M.-%) ought to be neglected, particularly since the polishing resistance of fine aggregate is higher than that of coarse aggregate. This paper aims to quantify the polishing resistance of various aggregate size fractions with particular focus on the properties of fine aggregate, and to demonstrate the suitability of the Wehner/Schulze test (W/S) in this regard. The results show that the initial skid resistance and the polishing resistance of fine aggregate are generally greater than that of coarse aggregate. It is notable that the initial skid resistance decrease is far more pronounced for fine aggregate. The polishing resistance does not exhibit a uniform development across all aggregate sizes. It is to be expected that fine aggregate may play a significant role for the skid resistance of asphalt pavements; however only coarse aggregate is considered in the design process. Further research is needed to precisely determine the effect of fine aggregate to allow for more economically feasible pavement designs.