Effects of Aggregate Shape Parameters and Gradation on High-Modulus Asphalt Mix Performance

2021 ◽  
pp. 647-653
Author(s):  
Taher Baghaee Moghaddam ◽  
Hassan Baaj
Keyword(s):  
Shape Parameters ◽  
High Modulus ◽  
Asphalt Mix ◽  
Aggregate Shape

scholarly journals Extending the Service Life of Pavements

2018 ◽  
Vol 26 (1) ◽  
pp. 25-32
Author(s):  
Ivan Gschwendt
Keyword(s):  
Asphalt Concrete ◽  
Building Materials ◽  
Road Construction ◽  
Pavement Management ◽  
High Modulus ◽  
Pavement Management System ◽  
Asphalt Mix ◽  
Degradation Models ◽  
The Cost ◽  
Whole Life Cost

Abstract The cost of road construction and expenditures on the maintenance of pavements, i.e., their whole life cost, represents a lot of money. The paper describes a procedure for a pavement management system with degradation models and estimates the length of time for the rehabilitation of an asphalt pavement. Using a theory of pavement mechanics, we calculated the stresses and strains on the layers of two pavement models. High modulus asphalt concrete, an asphalt mix with a high binder content, and an asphalt mix with binder modifications are new road building materials. Prolonging the time for the rehabilitation of pavements is possible.

Temperature implications on rheological-mechanical behavior and design of high modulus dense asphalt mix

2016 ◽  
Vol 125 ◽  
pp. 135-144 ◽  
Author(s):  
Breno Barra ◽  
Leto Momm ◽  
Yader Guerrero ◽  
Hazim Ali Al-Qureshi ◽  
Alexandre Mikowski ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
High Modulus ◽  
Asphalt Mix

scholarly journals Shape Characterizing of Aggregates Produced through Different Crushing Techniques

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1199
Author(s):  
Ghulam Yaseen ◽  
Wesam Salah Alaloul ◽  
Imran Hafeez ◽  
Abdul Hannan Qureshi
Keyword(s):  
Form Factor ◽  
Aspect Ratio ◽  
Shape Factor ◽  
Asphalt Mixtures ◽  
Volumetric Properties ◽  
Shape Parameters ◽  
Jaw Crusher ◽  
Factor Form ◽  
Marshall Stability ◽  
Aggregate Shape

The aggregate shape properties produced from the different crushing techniques influence the performance properties of the asphalt mixtures. The objective of this study was to classify the aggregates into spherical, flat, elongated and flat, and elongated shapes, collected from impact crusher and jaw crusher of two sources, and to calculate the shape parameters, such as aspect ratio, shape factor, form factor, sphericity, roundness, and angularity index. In addition, this study also investigated the effects of this classification on the Marshall stability and volumetric properties of asphalt mixtures prepared from the respective shape of aggregates. The results showed that the aggregate of different fractions (passing 37.5 mm and retained on 4.75 mm) produced from the jaw crusher of Margalla quarry showed better shape parameters. The spherical aggregates collected from all crushers showed 20–30% higher Marshall stability of the blends by improving the mechanical and volumetric properties of the asphalt mixtures.

scholarly journals Viscoelastic Mechanical Responses of HMAP under Moving Load

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2490 ◽  
Author(s):  
Yazhen Sun ◽  
Bincheng Gu ◽  
Lin Gao ◽  
Linjiang Li ◽  
Rui Guo ◽  
...  
Keyword(s):  
Dynamic Modulus ◽  
Tensile Strain ◽  
Mechanical Response ◽  
Asphalt Pavement ◽  
Moving Load ◽  
High Modulus ◽  
Wave Load ◽  
Mechanical Responses ◽  
Finite Element Software ◽  
Asphalt Mix

In order to represent the mechanical response laws of high-modulus asphalt pavement (HMAP) faithfully and objectively, the viscoelasticity of high-modulus asphalt mixture (HMAM) was considered, and the viscoelastic mechanical responses were calculated systematically based on moving load by numerical simulations. The performances of the HMAP in resistance to the deformation and the cracking at the bottom layer were compared with the ordinary asphalt pavement. Firstly, Lubao and Honeywell 7686 (H7686) were selected as the high modulus modifiers. The laboratory investigations of Asphalt mix-70 penetration, Asphalt mix-SBS (styrene-butadiene-styrene), HMAM-Lubao and HMAM-H7686 were carried out by dynamic modulus tests and wheel tracking tests. The conventional performances related to the purpose of using the HMAM were indicated. The master curves of the storage moduli were obtained and the viscoelastic parameters were fitted based on viscoelastic theories. Secondly, 3D pavement models based on moving loads for the viscoelastic structures were built using the non-linear finite element software ABAQUS. The wheel path was discretized in time and space to apply the Haversine wave load, and then the mechanical responses of four kinds of asphalt pavement were calculated. Finally, the sensitivity analysis was carried out. The results showed that the addition of the high modulus modifiers can improve the resistance to high-temperature rutting of the pavements. Except for the tensile strain and stress at the bottom of the underlayer, other responses decreased with the increases of the dynamic moduli and the change laws of the tensile strain and stress were affected by the range of the dynamic modulus. The tensile stress at the bottom of the asphalt layer would be too large if the modulus of the layer were too large, and a larger tensile strain would result. Therefore, the range of the modulus must be restricted to avoid the cracking due to excessive tension when using the HMAM. The resistance of the HMAP to deformation was better and the HMAP was less sensitive to load changes and could better withstand the adverse effects inflicted by heavy loads.

scholarly journals Correlations Between Aggregate Particle Shape Parameters and Size Based on Images Captured Using a 3-D Laser Scanning Device

2014 ◽  
Vol 15 (2) ◽  
pp. 27-36 ◽  
Author(s):  
Martin B. Mgangira ◽  
Julius Komba
Keyword(s):  
Particle Shape ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Free Form ◽  
Shape Parameters ◽  
Aggregate Particle ◽  
Laser Scanners ◽  
Aggregate Shape ◽  
Ideal Technique

Abstract Three dimensional (3-D) laser scanning has recently proved to be an ideal technique for quantifying aggregate particle shape parameters. This is because 3-D laser scanners measure fine details and capture free-form shapes. This paper presents some results of an on-going study, which utilises 3-D laser scanning technology to quantify aggregate shape parameters. Specific correlations and shape parameters have been considered. The results have shown that meaningful correlations exist between 3-D sphericity and aspect ratio as well as between specific surface area and the particle diameter as defined in this paper. The results of the current study are consistent with generally accepted relationships between shape parameters and particle size, further validating the application of the 3-D laser scanning technology

EXELFS Studies of Carbon Fibers

1990 ◽  
Vol 48 (2) ◽  
pp. 72-73
Author(s):  
V. Serin ◽  
K. Hssein ◽  
G. Zanchi ◽  
J. Sévely
Keyword(s):  
Carbon Fibers ◽  
Energy Analysis ◽  
Electron Excitation ◽  
Complex Structures ◽  
High Modulus ◽  
Promising Technique ◽  
X Ray ◽  
Fine Structures ◽  
X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

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