Modeling and characterizing the mesomechanical behavior of asphalt mixture with random aggregate distribution: A coupled topological-numerical method

2021 ◽  
pp. 635-640
Author(s):  
Cong Du ◽  
Pengfei Liu ◽  
Markus Oeser
Keyword(s):  
Numerical Method ◽  
Asphalt Mixture ◽  
Aggregate Distribution ◽  
Random Aggregate

Application of Fractal Theory in Aggregate Gradation Research

2012 ◽  
Vol 204-208 ◽  
pp. 1923-1928
Author(s):  
Bo Tan ◽  
Rui Hua Yang ◽  
Yan Ting Lai
Keyword(s):  
Fractal Dimension ◽  
Fractal Theory ◽  
Asphalt Mixture ◽  
Fractal Dimensions ◽  
Aggregate Gradation ◽  
Structure Characteristics ◽  
Aggregate Distribution ◽  
Dimension Formula ◽  
Mass Fractal ◽  
Fractal Characteristics

The paper presents the fractal dimension formula of distribution of asphalt mixture aggregate diameter by the deducing mass fractal characteristics function. Taking AC-20 and SMA-20 as examples, selected 6 groups of representative grading curves within the grading envelope proposed by the present specification, and calculated their fractal dimensions. The asphalt mixture gradation has fractal dimension D (D∈(1,3)), and the fractal of continuous gradation is single while the fractal of gap-gradation shows multi-fractal with 4.75 as the dividing point. Fractal dimension of aggregate gradation of asphalt mixture reflect the structure characteristics of aggregate distribution, that is, finer is aggregate, bigger is the fractal dimension.

scholarly journals Modeling of the Complex Modulus of Asphalt Mastic with Biochar Filler Based on the Homogenization and Random Aggregate Distribution Methods

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yushuai Wu ◽  
Peng Cao ◽  
Feiting Shi ◽  
Ketong Liu ◽  
Xuhao Wang ◽  
...  
Keyword(s):  
Complex Modulus ◽  
Coating Layer ◽  
Mineral Filler ◽  
Distribution Method ◽  
Asphalt Mastic ◽  
Aggregate Distribution ◽  
Consistent Model ◽  
Random Aggregate ◽  
Self Consistent ◽  
Asphalt Mastics

The disposal of agricultural straw has been a severe environmental concern in China and many other countries. In this study, the complex modulus of using biochar converted from straw as an alternative mineral filler in asphalt mastic was investigated through both laboratory tests and modeling. The experimental results indicated that the biochar can provide asphalt mastic higher stiffness than the conventional granite mineral filler. It was believed that the special porous structure of biochar providing a thicker coating layer of mineral filler increases the stiffness modulus of asphalt mastic. To consider this factor into the micromechanical model, a modified generalized self-consistent model (MGSCM) with a coating layer was proposed. Besides, the finite element (FE) microstructural model with a coating layer generated by random aggregate distribution method was used to numerically evaluate the effect of the coating layer on the complex modulus of asphalt mastics. The predicted results indicated that the generalized self-consistent model (MGSCM) with a coating layer is an efficient and accurate model for predicting the complex modulus of asphalt mastics. Moreover, the FE modeling proved that the coating layer can significantly improve the complex modulus of asphalt mastics. Therefore, the experiments and modeling carried out in this study provided insight for biochar applications to improve the performance of asphalt mixtures.

Considering Material Heterogeneity in Crack Modeling of Asphaltic Mixtures

2003 ◽  
Vol 1832 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Jorge Barbosa Soares ◽  
Felipe Araújo Colares de Freitas ◽  
David H. Allen
Keyword(s):  
Fracture Mechanics ◽  
Numerical Method ◽  
Laboratory Tests ◽  
Global Analysis ◽  
Asphalt Mixture ◽  
Local Scale ◽  
Monotonic Loading ◽  
Crack Evolution ◽  
Material Heterogeneity

Cracking in the asphaltic layer of pavement has been shown to be a major source of distress in roadways. Previous studies in asphaltic mixture cracking have typically not considered the material heterogeneity. A numerical method of analysis is presented that is based on the theory of fracture mechanics, in which the binder and the aggregates are treated as distinct materials. The simulations performed are verified and calibrated from simple and conventional laboratory tests. The study investigates crack evolution under monotonic loading, even though the method outlined can be further developed for the investigation of asphalt mixture fatigue. The approach discussed is part of a multiscale framework for pavement analysis, in which the damage due to cracking at the local scale can be considered in a global analysis at the actual pavement scale.

Random Aggregate Generation and Mesoscale Modeling of Concrete under High Strain Rate Compression

2011 ◽  
Vol 71-78 ◽  
pp. 733-736 ◽  
Author(s):  
Xiao Qing Zhou ◽  
Yong Xia
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Coarse Aggregate ◽  
High Strain ◽  
Concrete Specimen ◽  
Material Behavior ◽  
Mesoscale Modeling ◽  
Aggregate Distribution ◽  
Random Aggregate ◽  
Strain Rate Compression

In the mesoscale modeling, concrete is assumed consisting of three components, i.e., coarse aggregates, mortar matrix, and the interfacial transition zone (ITZ), each with different material behavior. The shape and the percentage of the coarse aggregate are the key factors in the mesoscale numerical simulation. The present paper investigates the effect of the coarse aggregate shape on the concrete behavior under high strain rate compression. Simplified methods are adopted to construct the aggregate distribution. Three different aggregate shapes, i.e., circular, oval and polygons, are generated to model the gravel and crushed stone aggregates, respectively. Using these different aggregate shapes, concrete specimens under high strain rate compression are modeled. Numerical results show that the aggregate shapes have a significant effect on the crack path, whereas little effect on the overall responses of the concrete specimen.

A Simple Method of Coarse Aggregate Generation Based on PFC2d

2013 ◽  
Vol 438-439 ◽  
pp. 149-152
Author(s):  
Yu Tian Kong ◽  
Juan Wang ◽  
Zong Kun Li ◽  
Li Hong Zhang
Keyword(s):  
Cross Section ◽  
Coarse Aggregate ◽  
Concrete Specimen ◽  
Two Dimensional ◽  
Mechanical Behaviors ◽  
Aggregate Model ◽  
Simple Method ◽  
Aggregate Distribution ◽  
Random Aggregate ◽  
Random Aggregate Model

To establish an appropriate random aggregate model at meso-level is the basis for successfully simulating the meso-mechanical behaviors of concrete. This paper proposes a new simple method to generate random aggregates of concrete by PFC2d. And the distribution of aggregate in the two-dimensional concrete specimen cross-section is determined by Walraven formula. The results show that the numerical aggregate distribution matches well with the theoretical grading curve.

scholarly journals Effect of Gradation Segregation on Mechanical Properties of an Asphalt Mixture

2019 ◽  
Vol 9 (2) ◽  
pp. 308 ◽  
Author(s):  
Wenliang Wu ◽  
Zhixian Tu ◽  
Zihan Zhu ◽  
Zeyu Zhang ◽  
Yongjie Lin
Keyword(s):  
Mechanical Properties ◽  
Asphalt Pavement ◽  
Contact Point ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Service Performance ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Vertical Load ◽  
Aggregate Distribution

Gradation segregation strongly affects the service performance of asphalt pavement. However, rare studies focus on the influences of segregation on asphalt mixture as it is difficult to simulate segregation in a laboratory. This paper presents a research aiming to evaluate the effects of gradation segregation using the two dimensional (2D) discrete element method (DEM). To achieve this objective, the gradation segregation levels are defined according to the differences between control and segregated gradations. Based on this, asphalt mixtures with three gradations at three segregation levels were selected. The corresponding 2D DEM models were then built using Particle Flow Code 2D (PFC 2D). The aggregate skeletons in the asphalt mixture were determined separately by means of the contact point and contact force. Based on this, the variations on the aggregate skeleton, aggregate distribution, and mechanical properties of the asphalt mixture under vertical load were studied at three different segregation levels. This study indicates that the aggregate skeleton in asphalt mixture can be affected by the gradation segregation. The correlation between gradation segregation and mechanical property is also determined in this study.

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