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Tan Y.-Q.,Harbin Institute of Technology | Xing C.,Harbin Institute of Technology | Zhang L.,Harbin Institute of Technology | Ren J.-D.,The Communications Research Institute of Liaoning Province
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2016

In order to research the effect of homogeneity on asphalt mixture strain field distribution and reveal the relationship between material distribution and strain field distribution, firstly, the strain field distribution of asphalt mixture in the indirect tensile test was obtained by digital image correlation method, and it was compared with gray level distribution. Secondly, the homogeneity index was proposed based on the gray level distribution for homogeneity evaluation, and the homogeneities of asphalt mixtures with different nominal maximum aggregate sizes were evaluated by homogeneity index. Finally, the relationship between homogeneity of asphalt mixture and strain field distribution was established by homogeneity index. The results show that greater gray level change appears in peak area of strain field, and there is smaller the gray level change in valley area of strain field. Homogeneity index method is effective for evaluating the local homogeneity of asphalt mixture. The homogeneity of the asphalt mixture with smaller nominal maximum aggregate size is better in the same evaluation scale. The peak value of strain field appears in the local area with higher homogeneity index, and the valley value of strain field appears in the area with lower homogeneity index. © 2016, Editorial Department of China Journal of Highway and Transport. All right reserved. Source


Chen J.,Dalian University of Technology | Liu J.,Dalian University of Technology | Liu Y.,The Communications Research Institute of Liaoning Province | Zhou C.,Dalian University of Technology
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2014

To understand in depth the behavioral characteristics of different asphalt pavements under traffic loads, the MLS66 accelerated loading facility was used to simulate actual vehicle running. The dynamic responses of semi-rigid pavement and inverted structured pavement in three directions were measured, and the strain responses at the bottom of the surface course and the bottom of the base course to the central load and eccentric load were studied respectively. The measurement showed that the value of the bending strain at the bottom of the base course of the semi-rigid structure was higher than that of the surface course. The inverted structure was more sensitive to the number of loading cycles because the value of the tensile strain in the inverted structure was much higher than that in the semi-rigid structure. The maximum tension strain in the inverted structure appeared on the bottom surface in the longitudinal direction, and fatigue cracking first appeared in the horizontal direction. The strain responses of both structures' surface course show the viscoelastic characteristics of the asphalt mixtures. The strain measurements under various loads indicate that the tire-pavement contacting pressure should be the primary estimating parameter when the overloaded vehicles are considered. The study of the dynamic responses of the pavement through the use of MLS66 helps to gain an understanding of the damage mechanisms of the various asphalt pavements. Source


Li Z.L.,Harbin Institute of Technology | Wu H.L.,Harbin Institute of Technology | Liu Z.Y.,Harbin Institute of Technology | Xu D.J.,Harbin Institute of Technology | And 2 more authors.
Applied Mechanics and Materials | Year: 2012

Fire effects cause one span of a frame underpass bridge in Harbin large area of different levels burning. Among them, some parts burned seriously; many adjacent beams turn black at bottom of roofs; parts of railings burned out of shape; parts decoration of side wall fractured, which blocked traffic towards Harbin. In order to make safety, repair on time, recovery traffic as soon as possible, satisfy the rules of original design and save money, this paper uses high strength non-shrinkage grouting material to repair stiffness of crack and damage concrete and carbon fiber to improve structure carrying capacity. Also, it uses middle support technique to reinforce the underpass bridge when repairing. Through a comparative analysis before and after reinforcement, paper confirms the feasibility and reliability of this repair design. © (2012) Trans Tech Publications, Switzerland. Source


Tan Y.-Q.,Harbin Institute of Technology | Ren J.-D.,Harbin Institute of Technology | Ren J.-D.,The Communications Research Institute of Liaoning Province | Xing C.,Harbin Institute of Technology | And 2 more authors.
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2014

In order to find out the warm mix mechanism of zeolite warm mix asphalt, the meso-structure of zeolite asphalt was studied. Dynamic nano particle analyzer, scanning electron microscopy and mercury porosimetry were used to analyze the granularity, mesoscopic features and pore characteristics of three kinds of zeolites; stereo microscope and X-ray CT technology were used to quantitatively analyze the two-dimensional and three-dimensional distribution of bubbles in three kinds of zeolite warm mix asphalts, and characteristic parameters of bubbles' distribution in zeolite-asphalt were thus determined, then the relationship between bubbles' distribution characteristic parameters and zeolite properties was established. The results show that synthetic zeolites have higher content of macropores, as well as bigger pore volume and smaller specific surface area than the natural ones. The bubbles produced by zeolite water have the distribution characteristics of "the upper the more and bigger, the lower the less and smaller"; the quantity of bubbles will decrease with the increase of temperature, yet the volume percentage will increase; zeolites with median pore that have small diameter and more mesopore and macropore are beneficial to the formation of the bubbles, which will promote the effect of warm mix, yet the large pore is not beneficial to forming bubbles, which contributes less to the effect of warm mix. Source

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