Query: fractal theory of asphalt concrete

title: Description of Surface Morphology and Skid Resistance of Asphalt Concrete Pavement with Fractal Theory
abstract: In order to describe the surface morphology and skid resistance performance,the gray contour of asphalt concrete pavement digital image is extracted to fractal analysis,the fractal parameters results show that the asphalt concrete pavement has significant fractal characteristics,the larger the fractal dimension,the more complex the asphalt pavement morphology;the larger the scale coefficient,the more coarse the asphalt concrete pavement texture.A roughness function,which combined with fractal dimension and scale coefficient,is put forward to the asphalt surface morphology.At the same time,it can also describe the complex degree and texture structure of asphalt concrete pavement.The test results show that the asphalt concrete pavement skid resistance performance and roughness function value has a good correlation,the greater the roughness function value,the better the skid resistance performance.

title: Research of AC 20 Grading of Conductive Asphalt Concrete Based on Fractal Theory
abstract: Aggregate distribution of asphalt mixture had an obvious characteristic of fractal. Based on fractal theory, the distribution function of aggregate of conductive asphalt mixture based on the granular fractal model was deduced. This paper used linear regression analysis to different gradings to get the grading fractal dimension of conductive asphalt mixture and the conductivity of the mixture was tested. Test results indicated that the grading fractal dimension of conductive asphalt mixture was controled by the fine aggregate. On the other hand, the fractal dimension had a congruent relationship with conductivity. The conductive asphalt mixture had good pavement performance and conductive when the fractal dimension of AC 20 grading ranged from 2.43 to 2.53. The fractal dimension can be used as a quantification index of grading evaluation.

title: Research on the homogeneity of asphalt pavement quality using X ray computed tomography (CT) and fractal theory
abstract: This paper presents an imaging method to assess the homogeneity of asphalt concrete using X ray computed tomography, the improved OTSU image method, and fractal theory. Specifically, this research attempts to analyse the principles of X ray computed tomography (CT) and to discover the cause of "dead pixels" in CT images. They are further processed by combining the annular block and OTSU methods. For this, the image is divided into several annular regions of similar brightness. The OTSU method divides the image into two parts, the object and the setting, for which the largest variance equals the least mistakes. Fractal theory can effectively calculate the complexity of the curves. Then, the fractal dimension can be calculated using the box counting dimension method. This article applies pavement quality indicators to test asphalt pavement and to choose four specimens with various degrees of segregation. A segregation evaluation standard based on fractal dimensions and the imaging method was established. By testing the physical indices, including the density, air void, strain, fatigue life and stiffness modulus of the specimens, it was concluded that the fractal dimension can define the 3D segregation of asphalt pavement well. The analysis also indicates that when the fractal dimension is relatively small, the boundary characteristics of the aggregate and mucilage will be relatively simple, and the uniformity coefficient will be larger with a shorter fatigue life.

title: Computation of fractal dimension on conductive path of conductive asphalt concrete
abstract: Distribution of the conductive paths in the conductive asphalt concrete seems as rough, disorder and random, but it has self similar fractal characteristics in statistics. It use the fractal theory to study on the distribution characteristics of the conductive paths. The conductive process of asphalt concrete turned from insulator to conductor could be described quantitatively by fractal dimensions. When the graphite content is 4 vol. 14 vol. the fractal dimension which is measured by box counting is 1.22 1.89. Comparing the relationship between fractal dimension and resistance change, it can be found that the changes in fractal dimension and resistivity have a similar trend with the changes of graphite content. There exists a percolation threshold when fractal dimension and the resistivity change, and the fractal dimension and resistivity change little once the graphite content exceeds the threshold. The physical significance of fractal dimension reflects the changes of the conductive paths in the asphalt mixture.

title: The Relationship between the Fractal Dimension and Mechanical Properties of Asphalt Concrete
abstract: The importance of the shape of aggregate particles on their mechanical behavior is well recognized. In asphalt concrete, the shape of aggregate particles affects the durability, workability, shear resistance, tensile strength, stiffness, fatigue response, and optimum binder content of the mixture. Due to their irregularity, the shape of aggregates is not accurately described by Euclidian geometry. However, fractal theory uses the concept of fractal dimension, DR, as a way to describe the shape of aggregates. This paper describes a study of the influence of fractal dimension on mechanical properties of asphalt concrete. The flow of asphalt concrete decreases and Marshall Stability increases when the fractal dimension of aggregate increases.

title: Estimation of fractal dimensions of conductive asphalt concrete based on fractal and percolation model
abstract: This paper introduces the fractal theory to the study on the distribution characteristics of the conductive paths of asphalt concrete by using fractal dimension to describe the conversion process when asphalt concrete are changed into conductor. Based on Matlab,the images information of the box counting dimension combined with the conventional image processing method is obtained. The relationship between fractal dimension and volume content of the conductive material was also analyzed. The results show that: the conductive path of asphalt concrete has obviously statistical significant similarity on fractal,and fractal dimension increases by the graphite content at two dimensional plane. In addition,the change trend of fractal dimension is similar to the dependence of resistivity and graphite content. The results indicate that fractal dimension can describe the degree of connectivity clearly and quantitatively when conductive asphalt concrete forming a percolation path.

title: Fractal features of cracking of self monitoring asphalt concrete
abstract: Self monitoring asphalt concrete has a good electrical behavior. The monitoring of damage is valuable for structural health monitoring and service life prediction. In this paper, the process of cracking of self monitoring asphalt concrete cracks were quantitatively described by indirect tensile test and combination of mathematical fractal theory. The test results show that the distribution of self monitoring asphalt concrete crack has obviously statistical similarity, and cracks with a clear statistical significance of cracks on the fractal. There is a good congruent relationship among fractal dimension, resistance and deformation, which provides a new thought to the research of the cracking of self monitoring asphalt concrete.

title: Fractal Analysis on Asphalt Mixture Using a Two Dimensional Imaging Technique
abstract: Fractal is a mathematical set that has a fractal dimension which usually exceeds its topological dimension and may be nonintegral. Since the asphalt pavement texture has limitations of randomness and self similarity, fractal theory has been explored to quantify the asphalt pavement texture and employs good applicability in processing and analyzing the complex details of research object. In this paper, the 2D digital image of the pavement surface is measured in terms of area fractal dimension and contour fractal dimension, which are used to correlate with aggregate gradation and British Pendulum Number (BPN) value, respectively. It turns out the area fractal dimension of aggregate provides a simple way to acquire the continuous gradation of asphalt concrete sample and the contour fractal dimension is an available parameter to characterize roughness and friction of pavement surface texture.

title: The Test Research about Gradation Design of Middle Asphalt Concrete
abstract: Relying on the fouth stage of the old cement concrete road surface engineering petrochemical asphalt mask in Canggui line,the article introduces the superpave gradation design method and bailey method and gradation design method based on the fractal theory,in order to study the gradation design of middle asphalt concretes.It also discusses the road performance through the Marshall test and freeze thaw splitting test.

title: Research on Optimization of Aggregate Gradation Design for AC 20 Asphalt Mixture in Airport Pavement
abstract: This paper investigates the AC 20 asphalt mixture based on "Specifications for asphalt concrete Pavement construction of civil airports" and put forward optimized aggregate gradation range by fractal geometry theory and bailey method,contrastive researches pavement performance of asphalt mixture between optimized aggregate gradation and standard aggregate gradation.The research indicates that the optimization of gradation consistent with the use of airport pavement and can be applied to airport pavement.The results shows that optimized aggregate gradation asphalt concrete has a better high temperature and water stability performance than standard aggregate gradation asphalt mixture.