scholarly journals Characterization of Three-Dimensional Internal Structure Evolution in Asphalt Mixtures during Freeze–Thaw Cycles

2021 ◽  
Vol 11 (9) ◽  
pp. 4316
Author(s):  
Gang Xu ◽  
Xianhua Chen ◽  
Xing Cai ◽  
Yunhong Yu ◽  
Jun Yang
Keyword(s):  
Internal Structure ◽  
Asphalt Mixture ◽  
Three Dimensional ◽  
Asphalt Mixtures ◽  
Structure Evolution ◽  
Void Content ◽  
3D Images ◽  
X Ray ◽  
Freeze Thaw ◽  
Before And After

This paper aims to characterize the three-dimensional (3D) internal structure evolution of asphalt mixtures under freeze–thaw cycles. Asphalt mixtures with three levels of design void content (3%, 5%, and 7%) were prepared in the laboratory. Subsequently, X-ray computed tomography (CT) tests were conducted to capture two-dimensional (2D) images of the internal structure of samples before and after freeze–thaw testing. A set of image processing techniques for reconstructing 3D images of the internal structure were utilized to extract the internal structure properties, which were then used to analyze the changes in the air void distributions and to evaluate the internal structure evolution under freeze–thaw cycles. 3D images reconstructed from X-ray CT images illustrated a dramatic degradation in the internal structure after cyclic freeze–thaw exposure. The change in internal structure occurs mainly in three ways: (1) expansion of existing individual voids, (2) combination of two separated air voids, and (3) generation of new voids. In addition, the parametric analysis of the three-dimensional reconstructed voids revealed that the asphalt mixture void ratio increased with the number of freeze–thaw cycles, while the larger the initial void content, the more pronounced the increase in the specimens. Therefore, asphalt mixture freeze–thaw resistance should be optimized in relation to the design void content.

scholarly journals Strength Criterion of Asphalt Mixtures in Three-Dimensional Stress States under Freeze-Thaw Conditions

2018 ◽  
Vol 8 (8) ◽  
pp. 1302 ◽  
Author(s):  
Tuo Huang ◽  
Shuai Qi ◽  
Ming Yang ◽  
Songtao Lv ◽  
Hongfu Liu ◽  
...  
Keyword(s):  
Asphalt Mixture ◽  
Three Dimensional ◽  
Strength Criterion ◽  
Failure Criteria ◽  
Asphalt Mixtures ◽  
Triaxial Tests ◽  
Axial Strength ◽  
Freeze Thaw ◽  
Stone Mastic Asphalt ◽  
Stress States

In order to study the influence of freeze-thaw cycles on the multi-axial strength of AC (Asphalt Concrete)-13 and SMA (Stone Mastic Asphalt)-13 asphalt mixtures which are widely used in China, triaxial tests were carried out in the laboratory. Two nonlinear failure criterions under three-dimensional stress states in octahedral space were established. A linear model for engineering design and its simplified testing method were then presented. The three-dimensional failure criteria of asphalt mixtures after 0, 1, 3, 5, 10, 15, 20 freeze-thaw cycles were also proposed. The results indicated that the multi-axial strength decayed significantly after 20 freeze-thaw cycles. It is noteworthy that the strength degrades rapidly during the first 5 freeze-thaw cycles. Compared with AC-13 asphalt mixture, the SMA-13 asphalt mixture exhibits better performance on the resistance to freeze-thaw damage, and it is recommended as the upper surface layer material of pavement structure.

Use of Imaging Techniques for Viewing the Internal Structure of Rubberised Asphalt Mixtures

2014 ◽  
Vol 695 ◽  
pp. 8-11 ◽  
Author(s):  
Norhidayah Abdul Hassan ◽  
Gordon Airey ◽  
Ramadhansyah Putra Jaya ◽  
Mohd Zul Hanif Mahmud ◽  
Nordiana Mashros
Keyword(s):  
Computed Tomography ◽  
Electron Microscope ◽  
Internal Structure ◽  
Imaging Techniques ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
X Ray ◽  
X Ray Computed ◽  
Rubberized Asphalt Mixture ◽  
Scanning Electron

This paper presents the application of different imaging techniques for viewing the internal structure of rubberized asphalt mixture as road materials. Two imaging techniques were used to capture the internal structure images of its compacted samples i.e. X-ray Computed Tomography (non-destructive method) and Scanning Electron Microscope, SEM (destructive method). Since a lot of previous researchers have produced extensive works on the mechanical properties, therefore, this study is an attempt to introduce the microstructure of rubberized asphalt mixtures produced using dry process method. Two types of dry mixed rubberized asphalt mixture were prepared by modifying a Hot Rolled Asphalt Mixture (HRA 60/20) with different crumb rubber sizes. A mixture of conventional HRA 60/20 was also scanned for comparison. The illustrations are aimed to provide the researchers more information regarding their internal structure distribution.Keywords: Imaging techniques, X-ray Computed Tomography, Scanning Electron Microscope, Rubberised Asphalt Mixture

X-ray microtomography

1988 ◽  
Vol 46 ◽  
pp. 998-999
Author(s):  
H.W. Deckman ◽  
B.F. Flannery ◽  
J.H. Dunsmuir ◽  
K.D' Amico
Keyword(s):  
Computed Tomography ◽  
Internal Structure ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Tissue Structure ◽  
Individual Element ◽  
X Ray ◽  
Non Invasive ◽  
Panoramic Imaging ◽  
Three Dimensional Images

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.

scholarly journals Ceramic Biomaterial Pores Stereology Analysis by the Use of Microtomography

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2207
Author(s):  
Żaneta Garczyk ◽  
Zbigniew Jaegermann ◽  
Piotr Duda ◽  
Andrzej S. Swinarew ◽  
Sebastian Stach
Keyword(s):  
Internal Structure ◽  
Pore Geometry ◽  
3D Images ◽  
X Ray ◽  
Research Material ◽  
Comparison Of The Results ◽  
Chemical Foaming

The main aim of this study was to analyze microtomographic data to determine the geometric dimensions of a ceramic porous material’s internal structure. Samples of a porous corundum biomaterial were the research material. The samples were prepared by chemical foaming and were measured using an X-ray scanner. In the next stage, 3D images of the samples were generated and analyzed using Thermo Scientific Avizo software. The analysis enabled the isolation of individual pores. Then, the parameters characterizing the pore geometry and the porosity of the samples were calculated. The last part of the research consisted of verifying the developed method by comparing the obtained results with the parameters obtained from the microscopic examinations of the biomaterial. The comparison of the results confirmed the correctness of the developed method. The developed methodology can be used to analyze biomaterial samples to assess the geometric dimensions of biomaterial pores.

scholarly journals Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Barbara Helena Barcaro Machado ◽  
Ivy Dantas De Melo E. Silva ◽  
Walter Marou Pautrat ◽  
James Frame ◽  
Mohammad Najlah
Keyword(s):  
Laser Treatment ◽  
Three Dimensional ◽  
Skin Surface ◽  
Clinical Scale ◽  
3D Images ◽  
Laser Resurfacing ◽  
Before And After ◽  
Measuring Outcomes ◽  
Skin Scar ◽  
Scientific Validation

AbstractMeasuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

Image processing procedure to quantify the internal structure of porous asphalt concrete

2019 ◽  
Vol 15 (1) ◽  
pp. 206-226 ◽  
Author(s):  
Kabiru Abdullahi Ahmad ◽  
Norhidayah Abdul Hassan ◽  
Mohd Ezree Abdullah ◽  
Munder A.M. Bilema ◽  
Nura Usman ◽  
...  
Keyword(s):  
Internal Structure ◽  
Asphalt Concrete ◽  
Functional Performance ◽  
Resilient Modulus ◽  
Asphalt Mixture ◽  
Content Type ◽  
Porous Asphalt ◽  
X Ray ◽  
Air Void ◽  
Aggregate Interlock

Purpose In order to fully understand the properties of porous asphalt, investigation should be conducted from different point of views. This is from the fact that porous asphalt mixture designed with the same aggregate gradation and air void content can give different infiltration rate due to the different formation of the internal structure. Therefore, the purpose of this paper is to investigate the micro-structural properties and functional performance of porous asphalt simultaneously. Design/methodology/approach The aim is to develop imaging techniques to process and analyze the internal structure of porous asphalt mixture. A few parameters were established to analyze the air void properties and aggregate interlock within the gyratory compacted samples captured using a non-destructive scanning technique of X-ray computed tomography (CT) throughout the samples. The results were then compared with the functional performance in terms of permeability. Four aggregate gradations used in different countries, i.e. Malaysia, Australia, the USA and Singapore. The samples were tested for resilient modulus and permeability. Quantitative analysis of the microstructure was used to establish the relationships between the air void properties and aggregate interlock and the resilient modulus and permeability. Findings Based on the results, it was found that the micro-structural properties investigated have successfully described the internal structure formation and they reflect the results of resilient modulus and permeability. In addition, the imaging technique which includes the image processing and image analysis for internal structure quantification seems to be very useful and perform well with the X-ray CT images based on the reliable results obtained from the analysis. Research limitations/implications In this study, attention was limited to the study of internal structure of porous asphalt samples prepared in the laboratory using X-ray CT but can also be used to assess the quality of finished asphalt pavements by taking core samples for quantitative and qualitative analysis. The use of CT for material characterization presents a lot of possibilities in the future of asphalt concrete mix design. Originality/value Based on the validation process which includes comparisons between the values obtained from the image analysis and those from the performance test and it was found that the developed procedure satisfactorily assesses the air voids distribution and the aggregate interlock for this reason, it can be used.

scholarly journals In Situ Coherent X-ray Diffraction during Three-Point Bending of a Au Nanowire: Visualization and Quantification

2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Anton Davydok ◽  
Thomas Cornelius ◽  
Zhe Ren ◽  
Cedric Leclere ◽  
Gilbert Chahine ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reciprocal Space ◽  
X Ray Diffraction ◽  
Complex Deformation ◽  
X Ray ◽  
Three Point Bending ◽  
Atomic Force ◽  
Au Nanowire ◽  
Before And After

The three-point bending behavior of a single Au nanowire deformed by an atomic force microscope was monitored by coherent X-ray diffraction using a sub-micrometer sized hard X-ray beam. Three-dimensional reciprocal-space maps were recorded before and after deformation by standard rocking curves and were measured by scanning the energy of the incident X-ray beam during deformation at different loading stages. The mechanical behavior of the nanowire was visualized in reciprocal space and a complex deformation mechanism is described. In addition to the expected bending of the nanowire, torsion was detected. Bending and torsion angles were quantified from the high-resolution diffraction data.

scholarly journals Laboratory Evaluation of the Use of Florida Washed Shell in Open-Graded Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7060
Author(s):  
Mohammad Alharthai ◽  
Qing Lu ◽  
Ahmed Elnihum ◽  
Asad Elmagarhe
Keyword(s):  
Tensile Strength ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Laboratory Evaluation ◽  
Void Content ◽  
Coarse Aggregates ◽  
Significant Difference ◽  
Indirect Tensile ◽  
Marshall Stability

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.

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