Papers by Keyword: Asphalt Concrete

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Authors: Xi Xiang Zhang, Chao Zhang
Abstract: This paper presents a novel FRP-ERBG-asphalt concrete pavement system for steel bridge decks. Based on the preliminary results of theoretical analyses and laboratory tests, this new system offers superior structural performance to conventional asphalt concrete pavement systems. Once trial tested in practice, it may well represent a new generation of reliable and economic pavement system for steel bridge decks.
Authors: Michele Buonsanti, Giovanni Leonardi, Francesco Scoppelliti
Abstract: The particles distinct element model has the consistency to model the mechanical behavior of the microscopic structures inside an asphalt mixture. The model assumes that the schematized granular constituents are in a contact point, considering the thin asphalt films as the binding elements. In this paper, we will model (at micro-scale) the damage to a surface in asphalt concrete under an impulsive load, considering binding, interface, viscosity and friction. Our aim is to reproduce the micro-damage due to detachment among the elementary components of the concrete in airports pavements.The proposed approach is mainly from a mechanical point of view, and a general model describing adhesive contact between rigid bodies is proposed. The intensity of adhesion is supposed to decrease under prescribed shear and normal displacement fields and comes by energy reduction, where the viscosity and friction contributes are taken in account.A numerical implementation by finite element procedures has been performed, and the outcome is presented.
Authors: Ya Zhen Sun, Zhao Yang Xin, Si Bo Zhang
Abstract: This paper uses Sidoroff damage model to research asphalt concrete (AC) trabecular tensile damage. Damage factor D is used to estimate the damage degree of AC. And the optimum position of grid overlay is obtained. In order to simulate the trabecula without grid and grid in different position, an AC trabecular bending test model is established in ABAQUS. From the analysis of AC damage, it can retard AC damage efficiently when grid overlay is located on the bottom of trabecula. The results of the research can offer the reference of controlling on damage cracking in the process of design and construction of asphalt pavement.
Authors: Martin Lidmila, Tomáš Zikmund, Jindřich Dvořák, Jozef Kaiser, Vít Lojda
Abstract: The extent of the use of asphalt concrete in track bed layers is minimal in contrast to the application of granular materials mostly represented by coarse/fine crushed stone mixture. This article summarizes advantages and disadvantages of the use of asphalt concrete in the track bed construction and provides relevant literature research. The main part of this article focuses on the application of recycled asphalt concrete (so called R-material) in the track bed layer and its following non-destructive X-ray Micro Computed Tomography Method (Micro-CT) for the description of its structural parameters. The contribution of this research is based on the evaluation of the air void and soluble binder content of chosen recycled asphalt concrete. First, it was obtained from laboratory geotechnical models of a railway track, and then from the following implementation in a trial section of an operating railway track. The conclusion contains results of the R-material practical application and findings from Micro-CT.
Authors: Piet Stroeven, Huan He, Pham Huu Hanh
Abstract: Paper presents and discusses data obtained in a testing program on the replacement of limestone powder in asphalt concretes by fly ashes. This would combine economic, environmental and technical benefits. The finest fly ash of Vietnamese origin scored best. This is proposed due to the gap-graded design of the particulate mixture of coarse crushed rock fractions, fine fluvial sand and the mineral admixture. The test program encompassed Marshall tests, creep tests and splitting tensile tests.
Authors: Ji Qing Zhu, Shao Peng Wu, Jin Jun Zhong, Dong Ming Wang
Abstract: Two classification methods for coarse recycled aggregate used in asphalt concrete were investigated in this paper, respectively classifying by coarse recycled aggregate properties and asphalt concrete properties. When classifying by coarse recycled aggregate properties, coarse recycled aggregate was classified into three types by the apparent specific gravity, water absorption, crushed value, Los Angeles abrasion value and brick content of coarse recycled aggregate. When classifying by asphalt concrete properties, coarse recycled aggregate was used to prepare asphalt concrete; and coarse recycled aggregate was classified into three types by the optimum asphalt content ratio (ROAC), theoretical maximum specific gravity ratio (RTMSG) and indirect tensile strength ratio (RITS) of asphalt concrete containing coarse recycled aggregate. The proposed classification criterions of the two classification methods were respectively given.
Authors: Yi Han Sun, Shao Peng Wu, Ji Qing Zhu, Jin Jun Zhong
Abstract: Two classification methods for fine recycled aggregate used in asphalt concrete were investigated in this paper, respectively classifying by fine recycled aggregate properties and asphalt concrete properties. When classifying by fine recycled aggregate properties, all test results of fine recycled aggregate properties can meet the technical requirements of China with obvious differences in quality. When classifying by asphalt concrete properties, fine recycled and natural aggregate was respectively used to prepare asphalt concrete with the same gradation, the same asphalt, the same limestone mineral filler and the same coarse natural aggregate. Some related properties of asphalt concrete were discussed to classify fine recycled aggregate. It is proposed in this paper that fine recycled aggregate should be classified into three types by asphalt concrete properties and the proposed classification criterion is given.
Authors: Li Qun Zhou, Yu Ping Li, Hong Liu, Guo Xing
Abstract: So as to design the pavement planer, it is necessary to study the milling performance of asphalt concrete. In this work, a coupled thermo-mechanical plane-strain large deformation orthogonal cutting finite element model is presented to simulate the asphalt concrete milling process and predict the stress and temperature field on the cutter. Chip separation is considered by applying shear fracture failure criteria and element deletion and adaptive mesh technique. Two contact pairs are defined. Contact pair 1 defines the milling path, and contact pair 2 defines to prevent the formed chip enter into the workpiece. The Johnson-Cook’s constitutive relation is adopted for the asphalt material. The cutter surface friction and heat conduction are considered. The computation indicates that the maximal cutting force will change from 3.967KN to 10.494KN if the cutting speed is between 1000mm/s and 2000mm/s for the pavement planer of BG2000.
Authors: Hong Zhang, Xiao Hua Wu, Xiao Lei Wang
Abstract: Using SMA -16 (Stone Mastic Asphalt) non-continuous close-graded, a self-made polyaniline / PP (PANI / PP) compound conductive fiber was investigated as electric conduction phase, a new type of conductive asphalt concrete was prepared. The conducting performance tests shown that the conductivity of conductive asphalt concrete logarithmic changed from -12.67 to -6.67, increased by 6 orders of magnitude, and the percolation threshold was 1%. The scanning electron microscopy (SEM) shown that conductive fibers dispersed equably in asphalt concrete. Conduction mechanism of conductive asphalt concrete can be described as "an island - network" model and with the fiber fraction increased, the distribution of the conductive fiber turned from "isolated island" model to "conductive network chain" ,and at the same time the asphalt concrete changed from insulating to conducting accordingly. According to classical percolation theory, a filling factor F and network factor n was introduced, so that determined the meaning and value of the parameters, and established the electrical conductivity of conductive asphalt concrete theoretical formula. The theoretical results were in good agreement with the measured values.
Authors: Islam Md Rashadul, Mekdim T. Weldegiorgis, A. Tarefder Rafiqul
Abstract: This study has developed a relationship between the Dynamic Modulus (E*) and the Indirect Tensile Strength (ITS) of Hot-Mix Asphalt (HMA) using standard laboratory tests programs. Two types of SuperPave (SP) mixtures were considered namely, SP-III with 15% Reclaimed Asphalt Pavement (RAP) materials and SP-III with 35% RAP materials. Cylindrical samples of 100 mm diameter and 150 mm height were prepared. The samples were then tested for |E*| value at 210C at several loading frequencies following the AASHTO TP 62-07 test protocol. Next, the samples were cut into circular pieces of 38 to 50 mm thickness using laboratory saw. The samples are then tested for ITS value by applying a deformation rate of 50 mm per minute (AASHTO T 283 protocol). The ITS was calculated following the AASHTO T 283-07 test standard. The |E*| values (MPa) of SP-III with 15% RAP at 25, 10, 5.0, 1.0, 0.5, 0.1 Hz are measured to be 65, 59, 52, 34, 31, and 18 times of ITS (psi) respectively. The |E*| values (MPa) of SP-III with 35% RAP at 25, 10, 5.0, 1.0, 0.5, 0.1 Hz are measured to be 41, 38, 33, 24, 20, and 14 times of the ITS (psi) respectively. This study also draws a conclusion that increase in RAP has resulted in increased stiffness and strength.
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