Macro Texture Research Articles

Electrolyte jet tomography: Three-dimensional microstructure mapping with an electrochemical machine tool and an optical microscope

There is a general separation between the manufacturing processes that add value to materials on the factory floor and the techniques engineers use in the laboratory to evaluate the microstructures and the surface integrity that results. These techniques are often destructive or require a vacuum and are incompatible with production lines. However, this information has intrinsic value and could be exploited to inform production decisions during manufacture. In this study, a novel approach to acquire this information is presented that is underpinned by electrolyte jet machine tool coupled with optical microscopy, which can allow the extraction of both grain-wise partial orientation and morphological information, and crystallographic macro textures in three dimensions. Here, iterative sections are precisely machined into the near surface of a commercially pure titanium alloy using an electrochemical jet and subsequently imaged, allowing the reconstruction of high-fidelity microstructure models rapidly and under ambient conditions. In doing so, new insights into the specific orientation-dependent dissolution mechanisms are offered, and the acquisition of appropriate conditions that result in nanoscale roughness surfaces (avoiding the dominance of pitting and preferential grain removal) is firstly explored. Building on prior work, a piecewise approach is presented to analyse the acquired image stacks to map partial crystal orientations, while different approaches are proposed to account for jet-specific surface artefacts and waviness. This is repeated over 20 layers in an individual specimen and layer-wise orientation maps are used to construct volumetric models of the specimen. These data sets are then explored from the perspective of materials/manufacturing engineers, who may use to this information to effect advancements to materials processing technologies.

The effect of aggregate micro and macro texture on pavement skid resistance of Malaysia road network

The effect of aggregate micro and macro texture on pavement skid resistance of Malaysia road network

Study on Hot Deformation Behavior and Microstructure Evolution of MgAlCuZnMnCe Alloy

The Mg79Al12.5Cu2.5Zn4MnCe multi-principal element alloys was prepared by induction melting under a high-purity argon. The true stress-strain curves at deformation temperatures of 250-350°C and strain rates of 0.001-1s−1 were used to establish the constitutive equations as well as the thermal processing map. The optimal hot processing parameters for the alloy were determined as a deformation temperature of 320-350°C and a strain rate of 0.1-1s−1. Further investigation into the impact of various deformation parameters on the microstructure and macrotexture of the alloy during hot compression was conducted. The findings indicate that at a deformation rate of 1s−1, the second phase of the alloy is broken and deformed. The texture intensity follows a pattern of initially decreasing and then increases as the temperature rises. The change in grain size is influenced by the deformation crushing effect, initiation of the non-substrate slip system, and grain growth. When the strain rate increases, the changes in texture intensity and distribution are not pronounced, indicating that the strain rate has minimal influence on the macro texture.

Crystallographic orientation dependence of dynamic deformation behaviours in additively manufactured stainless steel

This study reveals the dynamic compressive deformation anisotropy among 316L stainless steel fabricated via wire and arc additive manufacturing process(WAAM). Cylindrical samples extracted from as-built WAAM 316L plate with 35°, 45°, 55°and 90° from scanning direction, were referred to as <111>, <110>, <112> and <100> crystallographic orientations hereinafter, which had been confirmed through backscattered diffraction. Cylindrical samples were subjected to dynamic tests by a split Hopkinson pressure bar. The corresponding mechanical behaviors and deformed microstructures are associated. There are approximately 10% higher dynamic flow stresses from the <111> samples than other samples during dynamic tests at strain rates less than 3500 s−1, which can be attributed to lower density of thinner deformation twins. The lower tendency towards deformation twinning in <111> samples arises from the increase of effective stacking fault energy. WAAM 316L presents an anisotropy of resistance to adiabatic shearing, of which the order is < 100>, <110>, <112> and <111>. Two adiabatic shear bands(ASB) in <111> sample present distinct orientation characters, where the sub-grains in the first ASB show <111> and <112>-fiber while that in the subsequent one take <110>-fiber. This micro-texture discrepancy from two ASBs could be contributed to the precondition change of macro texture in the matrix which give birth to.

Study of Tire–Pavement Noise Acoustic Performance in Resilient Road Pavement Made of Strain-Hardening Cementitious Composites

A modified strain-hardening cementitious composite (SHCC) material, fabricated using corundum aggregates (SHCC-Cor), has been proposed for roadway applications as it offers high structural performance and high skid resistance. However, the acoustic performance of SHCC is unclear and has not been well studied in the past. Theoretically, SHCC may not provide the optimum solution in acoustic performance as it provides a low texture profile, high density, and low porosity. In this study, the acoustic performance of pavement slabs made of SHCC and modified SHCC-Cor are investigated using a nondestructive method to determine the surface roughness (macro texture) of slab surfaces. The pavement–tire noise level was then simulated using SPERoN software. As result, the noise level coming from the pavement made of SHCC could be up to 65 dB(A), while the noise level for SHCC-Cor increased up to 69.2 dB(A) because of the lower shape factor (G) due to a rougher surface as a result of the existence of corundum aggregate on the SHCC surface. The aeroacoustics were also increased compared to the SHCC slab. The modification of SHCC-Cor by introducing grooves (SHCC-Cor-Gro) successfully reduced the sound level coming from the vibration.

Data Augmentation and Intelligent Recognition in Pavement Texture Using a Deep Learning

As one of the most important properties of road, the adaption to roads with different macro-textures may significantly affect the autonomous driving technologies since road texture directly affects the skidding resistance and tire noise. Therefore, it is of great significance to detect and analyze the road macro texture with respect to different pavement types and service conditions. Generally, transportation engineers may face problems such as small dataset size, unbalanced dataset, etc. To solve these problems, this study aims to recognize the pavement texture using the deep learning approaches. The pavement texture data was first visualized using image processing methods, and then augmented using the traditional methods as well as a deep learning approach, i.e. Generative Adversarial Network (GAN) model. The Random Forest (RF) algorithm and the DenseNet network were both employed, where the overall classification accuracy of the original dataset was 50% and 59%, respectively, and the accuracy of the data augmented by the traditional methods was 58% and 70%, respectively. Test results show that, after 250,000 generations of training, GAN model was able to generate new pavement texture images with high quality, and the classification accuracy on the test dataset using DenseNet improved to 82%. It was discovered that the deep learning methods had a better performance for pavement texture recognition than manual classification and traditional machine learning methods. Furthermore, it was also found that adding noise in the original datasets as an augmentation method had a negative impact on the classification accuracy.

Texture Image Analysis for Larger Lattice Structure using Orthogonal Polynomial framework

An Orthogonal Polynomial Framework using 3 x 3 mathematical model has been proposed and attempted for the textureanalysis by L.Ganesan and P.Bhattacharyya during 1990. They proposed this frame work which was unified to address both edgeand texture detection. Subsequently, this work has been extended for different applications by them and by different authors overa period of time. Now the Orthogonal Polynomial Framework has been shown effective for larger grid size of (5 x 5) or (7 x 7) orhigher, to analyze textured surfaces. The image region (5 x 5) under consideration is evaluated to be textured or untextured usinga statistical approach. Once the image region is concluded to be textured, it is proposed to be described by a local descriptor,called pro5num, computed by a simple coding scheme on the individual pixels based on their computed significant variances. Thehistogram of all the pro5nums computed over the entire image, called pro5spectrum, is considered to be the global descriptor.The novelty of this scheme is that it can be used for discriminating the region under consideration is micro or macro texture,based on the range of values in the global descriptor. This method works fine for many standard texture images. The works usingthe proposed descriptors for many texture analysis problems with (5 x5) including higher grid size and applications are underprogress

Annealing texture in asymmetrically rolled Ni1.5FeCrCu0.5 high-entropy alloy

Asymmetrical cold rolling (ACR) was conducted on Ni1.5FeCrCu0.5 high-entropy alloy (HEA) with various velocity ratios (VRs) between the top and bottom rolls from one to eight. The crystallographic texture evolution in the annealed samples was investigated using the X-ray diffraction (XRD) method. Macro texture measurements revealed that the asymmetrical cold rolling increased the intensity of shear texture components such as E {111} <110> and F {111} <112> orientations. It was found that recrystallization was unfavorably suppressed by the low stacking fault energy (SFE) of the alloy. The results indicated that increasing the VR of the rolls led to the formation of Goss {011} <100> and Goss/Brass {011} <115> orientations in the annealed HEAs. Moreover, the Cube {001} <100> component in the homogenized sample disappeared by the post-roll annealing. However, the intensity of Brass {011} <211> orientation almost remained unchanged (⁓3 × R) in the annealed samples. Our findings showed that the increase in the VR of the rolls gave rise to a continuous rotation of 25° from the S {123} <634> orientation towards the Brass {011} <211> component in the annealed HEAs. Finally, plastic anisotropy measurements revealed that the drawability of the annealed sheets was continuously improved by increasing the VR of the rolls.

Characterization of Counter-Surface Substrates for a Laboratory Abrasion Tester (LAT100) Compared with Asphalt and Concrete to Predict Car Tire Performance

Tire performance is determined based on the interaction between the tire and the road as a counter-surface, and is of the utmost importance for driving safety. When studying tire friction and abrasion, the characteristics of the roads/counter-surfaces are crucial. The excitations on the tire come from the road asperities. A proper characterization of the counter-surface texture is, therefore, an absolute necessity in order to optimize tire performance. The present study provides the required knowledge over the counter-surfaces employed as common substrates in a Laboratory Abrasion Tester (LAT100), which are typically based on embedded corundum particles for dry/wet friction and abrasion experiments. All surfaces are scanned and characterized by laser microscopy. The surface micro and macro roughness/textures are evaluated and compared with asphalt and concrete as the real roads by power spectral densities (PSD). The reliability of the high-frequency data based on the device type should be considered carefully. The reliable cut-off wavenumber of the PSDs is investigated based on image analyses on the range of tested frequency for micro and macro textures obtained by optical scanning devices. The influence of the texture wavelength range on the rubber−surface interaction is studied on a laboratory scale.

RPAS BASED TRACKING OF MACHINERY USED IN ASPHALT PAVING PROCESS

Abstract. Application of rigorous construction procedures is fundamental when it comes to road construction. Nowadays, and in particular in Chile, the asphalt paving construction process is based on tradition, craftsmanship and other implicit, experience-based methods employed during road construction. This means, that the different stages of the construction process, including the paving of the road, are not controlled on time as they should, which causes that the final product does not have the ideal characteristics for which the construction materials initially were designed and manufactured. Therefore, we propose the use of tools and methodologies that allow monitoring each of the stages of the construction process in almost real-time. Our approach aims to evaluate the use of Remotely Piloted Aircraft Systems (RPAS) during the asphalt pavement construction process by capturing images and videos during the placement of the asphalt mixture and the movement of the compaction machinery (pneumatic roller and drum roller) present in the construction site. The observations are digitally processed by mainly binarization and thresholding. As a result, the macro texture of the asphalt surface was estimated and the trajectory of the compaction rollers was visualized. In conclusion, our results reveal that the main factor that influences the quality of the roads corresponds to the performance and operations of the compaction machinery.

Design on progressive corners of dies and macro textures of blank holders for S stamped parts

The shape dimensions of die corners and surface textures of blank holders are important in the effective control of twist springback. For predicting springback accurately, a mixed hardening model is presented for a thin-walled S beam made from TRIP780. Based on a proposed evaluation index for twist springback, the experiments of stamping and twist springback for TRIP780 are carried out. The twist springback angle is gauged by a three-coordinate measure instrument. A Response Surface Model (RSM) between the parameters of the mixed hardening model and the twist springback angles is established, and the parameters are inversed. The progressive die corners are designed for the twist springback compensation based on the stress distribution of the thin-walled S beam after stamping, and the die corner radius is optimized by the RSM and an Ant Colony Algorithm (ACA). Meanwhile, the macro textures of blank holders including longitudinal texture and transverse texture are designed. Based on the compensation analysis, a comprehensive compensation method which combined the progressive die corners with the longitudinal texture of the blank holder is proposed. The results show that the springback angle is reduced by 33.6%, proving the proposed comprehensive compensation method is effective.

The effect of mineralogy and grain size of fine aggregate and different surface textures on the durability of the RCCP surface toward abrasion conditions

The roller-compacted concrete pavement (RCCP) surface is almost smooth and without texture due to the vibrating rollers in the construction process. The lack of texturing causes a decrease in skid resistance in RCCP. For this purpose, different scenarios were proposed to create surface texture at micro and macro levels and provide the necessary friction. To provide friction at micro-scale, siliceous and calcareous sand and a combination of 50-50 of them with broken and natural aggregate shape was used in the construction of 8 RCCP mixing designs. In addition, in order to provide macro-texture, each of the eight mixing designs was texturing by methods such as seeding (three cases), stamping (two cases), and brooming (two cases). The purpose of this paper is to investigate the durability of various micro and macro textures created on RCCP surfaces by the simulation method proposed in the ASTM C 944 standard. The results showed that different textures have almost the same abrasion resistance. Among these, the seeding texture with the grain size of 4.75-9.5 mm has the weakest, and the stamp texture of 4 x 4 cm has the most durable abrasion resistance. Changes in abrasion resistance were associated with more changes in the mixing design. This means that crushed silica sand had the highest and natural lime sand had the lowest abrasion resistance. The results demonstrated that the combination of calcareous and siliceous materials improves abrasion resistance. In this regard, the higher the fracture rates of combined sand, the better the abrasion resistance.

2D-wavelet based micro and macro texture analysis for asphalt pavement under snow or ice condition

In ice and snow weather, the surface texture characteristics of asphalt pavement change, which will significantly affect the skid resistance performance of asphalt pavement. In this study, five asphalt mixture types of AC-5, AC-13, AC-16, SMA-13, SMA-16 were prepared under three conditions of the original state, ice and snow. In this paper, a 2D-wavelet transform approach is proposed to characterize the micro and macro texture of pavement. The Normalized Energy (NE) is proposed to describe the pavement texture quantitatively. Compared with the mean texture depth (MTD), NE has the advantages of full coverage, full automation and wide analytical scale. The results show that snow increases the micro-scale texture because of its fluffiness, while the formation of the ice sheets on the surface reduces the micro-scale texture. The filling effect of snow and ice reduces the macro-scale texture of the pavement surface. In a follow-up study, the 2D-wavelet transform approach can be applied to improve the intelligent driving braking system, which can provide pavement texture information for the safe braking strategy of driverless vehicles.

Evolutions of Mechanical Properties and Macro Textures of AZ91D sheets by Hot Rolling and Subsequent Annealing

The mechanical properties and textures of 75% hot unidirectionally rolled and cross rolled commercial magnesium die-casting alloy AZ91D sheets were investigated for the different rolling temperatures 623K and 673K, respectively. As for mechanical properties, tensile testing results show total elongations of both as-unidirectional and as-cross-rolled sheets are enhanced by the repetition of rolling passes and inter-pass heating. The planar anisotropy of tensile strengths and elongations of cross-rolled at 673K are the smallest among the rolling conditions employed in the present study. Annealed sheets demonstrate the significant elongation to failure due to the static recrystallisation at 623K. Macro textures of the as-unidirectional-rolled sheets show typical double-peak (0001) basal textures with inclined peaks towards ±15° in RD. Contrastingly, macro textures of the as-cross-rolled sheets show the significant (0001) basal textures having double peaks at ±10° in TD and concentrically broader orientation distribution in RD and TD.

Evaluation of the use of steel slag in micro surfacing

Micro surfacing (MS) is a type of bituminous coating frequently applied in the surface of pavement structures in order to prevent the occurrence of common distress and/or as a maintenance procedure. Micro surfacing has successfully been used in some states of Brazil as well as in many countries all over the world. Local aggregates used for micro surfacing composition are in some cases scarce and/or expensive. Therefore, the main objective of the present research is to verify the technical, financial and environmental viability of using steel slag aggregate (SSA) in micro surfacing applications. To reach the main objective, a procedure was developed in four steps. In the first step it was made the characterization of conventional (granitic) and alternative aggregates (steel slag) and polymer-modified emulsified asphalt. In the second step, mix design, surface abrasion resistance and setting time tests were performed. In the third step, the micro surfacing mechanical performance was analyzed using a laboratory traffic simulator to observe accumulated permanent deformation; surface wear; micro texture and macro texture. In the fourth step, a comparative study of costs concerning micro surfacing application using conventional mineral aggregate (MS-MA) and alternative aggregates (MS-SSA) were performed. The laboratory procedure results indicated that the steel slag studied has the potential to be used in micro surfacing applications with more rutting resistance and better durability. The cost analysis showed for medium transport distances bigger than 60 km, the MS-SSA will be cheaper than MS-MA solution.

Pre-concentration at crushing sizes for low-grade ores processing – Ore macro texture characterization and liberation assessment

Mineral processing of low-grade ores requires high processing flow rates. Pre-concentration is a clever technological solution for this challenge because the rejection of barren rock, in the early stages of the processing flowsheet, leads to increasing the head grade of the concentration plant and reducing the corresponding input flow rate.As pre-concentration at crushing sizes depends on the ore texture and consequently, it relies on the achieved mineral liberation degree, a straightforward methodology to assess quantitative mineralogical data of the ore macro-texture, based on image analysis, was developed.For the purpose, photos of hand samples collected at the mine site were converted into a digital image representative of the ore macro-texture. Then, a random comminution algorithm simulating a coarse crushing stage, to generate particles in size range 19.3/6.7 mm was applied. The surface grade of each particle was calculated by pixel counting, allowing for the computation of the Grade Histograms (wt%) and then for the construction of ultimate upgrading descriptors, which has been proved to be a useful tool to assess pre-concentration feasibility and the separation efficiency.This methodology was applied to a Li-Mica lepidolite ore from Alvarrões deposit (Portugal) by simulating several separation scenarios. The separation efficiency of an optical sorting separation was also assessed using the proposed methodology. Furthermore, the influence of mineral liberation at different size ranges on the global separation efficiency was predicted.This paper intends to underline the importance of quantitative mineralogical data in the study of the pre-concentration process. Data acquisition must be improved, taking advantage of the more accurate and faster systems, such as the modern multispectral analytical devices and ore sorting technologies.

Implementation of a GIS-based pilot application for roads management applied to the conservation and maintenance of unpaved low traffic roads

The lack of updating and unreliability of information has become one of the main problems that occur in the area of management of unpaved roads in developing countries as Colombia. Therefore, a GIS-based application was developed which allows keeping updated all the information at the structural and functional level of the road, and to control the premature pavement deterioration favouring the support for making decisions in management activities of the unpaved road network. In the municipality of Urrao (Antioquia), a research proposal on “La Encarnación” road was proposed. The Road Trial Section (RTS) is part of a bidirectional 3rd level road, which has 240 m-length and a 4 m-width. The RTS was divided into eight segments or cells (30 m-length), where each of them was stabilized with different conventional and unconventional materials (cement, hydrated lime, coal ash, brick dust, sulfonated oil, polymer and sugarcane sludge). Based on the results gathered in six pavement performance follow-up and evaluation campaigns, a geospatial database (GDB) was designed. This GDB is the core of the application “SGVVT Urrao v1.0” which is able to represent graphically the behaviour of the tests of functionality and the bearing capacity carried out (International Roughness Index, slip resistance, surface macro texture, lightweight deflectometer and visual inspection). The application is able to forecast the deterioration values allowing the prioritization of rehabilitation activities for the most affected sections in a given time period which is possible to extend the useful life of the roads, reduce the operation cost of the vehicles, and guarantee the road safety and the comfort of the unpaved road network users.

Field evaluation of a handheld laser meter for pavement surface macro texture measurement

ABSTRACT In the past, pavement surface texture has primarily been measured using volumetric methods, with the sand patch test the most common. However, handheld laser-based devices are now available for measuring a surface profile depth, which is converted to an estimated surface texture. Comparative measurement of 21 different pavement surfaces, of six different types, indicated that the results were consistently less variable for the laser-based device, compared to the sand patch results. The standard (linear) conversion from laser meter profile depth to estimate texture depth was adequate for typical asphalt surfaces (surface texture 0.5–1.5 mm) but an alternate (quadratic) conversion was recommended for better agreement between the laser meter and sand patch results for surfaces with lower (<0.5 mm) and higher (1.5–3.0 mm) surface textures.

Chip sealing macro texture performance evaluation using split-plot repeated measures

Chip seal is a pavement preservation technique that is preferred by agencies to defer future rehabilitation activities. The objective of this paper is to provide a very beneficial yet simple way to examine the effectiveness of chip seal as a pavement preservation technique and understand the effect of factors such as seal type, age of pavement and their interaction effect on performance. The research provides a carefully designed experimental plan to evaluate chip seal macrotexture properties using a split-plot repeated measurement (SPRM) statistical analysis. Selected emulsified and hot applied roadways in Klamath Falls were examined for their mean texture depth (MTD) using sand circle testing procedure at four consequent time points: (pre-seal application, within one week of seal application, 1-year, and 2-year post-seal application). Findings show that using chip seal have led to a statistically improved macrotexture performance of sealed roadways when compared to their pre-seal texture condition. Both emulsified and hot applied roadways have acquired satisfactory performance during the two-years monitoring period. Statistical analysis results further showed that both seal type and the environmental aging of pavements had a significant effect on roadways mean texture depth values. The study further emphasised that the interaction effect of seal type and time of experimentation had a very significant effect on the MTD performance.

Threshold value of skid resistance and texture depth for Malaysia road

Skid resistance is an important pavement characteristic for roads, which determines the friction between the road surface and vehicle tyres. The level of friction is largely influenced by the pavement surface aggregates micro texture, macro texture, and drainage attributes. The objective of this paper is to present the findings of the research and analysis conducted on Skid Resistance Value (SRV), Mean Texture Depth (MTD) and Skid Number (SN) obtained from the data collected on federal roads over the years since 2008. This research also attempted to determine the appropriate limiting values for SRV (microtexture), MTD (macrotexture) and SN for the federal roads. The result of analysis indicated that the average value of SRV at the locations of wet surface accident is 52.31 + 8.54. While for MTD, the accident risk is higher when MTD value is below the average of 0.45 + 0.025. The SRV and MTD results were correlated to each other and it can be concluded that accident risk increases significantly when SN value is below the average value of 31.49 + 7.87. Based on these findings, it is concluded that the minimum desirable values for SRV and SN for Malaysia’s Federal roads to be 55 and 30 respectively.