Papers by Keyword: Pavement Engineering

Abstract: Through the crush value test and combustion method test to analyze the relationship between needle flake content and crush value，and analyze the affection to the status of broken at compaction procession .Through the use of static pressure, gyratory compaction and Marshall compaction this three different molding methods of rubber asphalt mixture specimen shape.At the same time, analyze the variation of volume parameters and combination with the methods of specimen trimming to analyze its porosity distribution. At the same time, forming the sample volume parameters and combination of slices to analyze the porosity distribution of three different ways. The same time, through combustion method to analyze the impact of molding methods on rubber asphalt mixture's compaction characteristics.

Abstract: In order to further reveal the shear property of asphalt mixtures, shear device self-developed was used to research the variation and impact factor of anti-shear strength, cohesion and internal friction angle of different asphalt mixture types. The results show that: Modified asphalt can effectively improve the cohesion and anti-shear strength, but little effect on the internal friction angle; the internal friction angle and anti-shear strength of SAC-16 are greater than AC-16, but the cohesion is not significant different; with the nominal size of stone increased, the internal friction angle and anti-shear strength of asphalt mixtures rose, but little change in the cohesion; with temperatures increased, the anti-shear strength and cohesion of asphalt mixtures reduced gradually, but little change in the internal friction angle.

Abstract: To design the planning of excavating step on widening engineering of expressway reasonably, three-dimensional finite element method is used to analysis the influence of relative position between load and joint and step thickness combination of asphalt layer on the stress state of widening pavement. It is indicated from the results that step of asphalt layer should be under the marking or middle of the lane. To the double step of old asphalt layer, increase the thickness of lower step can improve the stress state of widening pavement, and joint of base layer step shouldn’t 0.4m away from load. Step planning can affect the maximal shearing stress of joint surface obviously, the index can be use to control construct quality of pavement widening engineering. The conclusion can be use as reference on excavating step for pavement widening engineering.

Abstract: In order to study the influence of reinforcement on the distribution of dynamic deviator stress along the depth of subgrade, reinforced and unreinforced subgrade of graded-broken-stone-based asphalt concrete pavement under traffic loading was modeled by implicit dynamic FEM. Analytical results show that reinforcement can improve the vertical compressive stress distribution, and decrease shear stress transmitted to the surface of subgrade. The deviator stress on the upper part of reinforced subgrade is reduced distinctly, which is one of the key factors that can cause residual deformation. Therefore, reinforcement can restrain the development of residual deformation of subgrade induced by traffic loading.

Abstract: When the ordinary concrete is added to fly ash, the slump of concrete is increased and the workability and pumpability are also improved, which can meet the design requirement, reduce project costs, protect environment and save resources. Based on evaluation of the basic performance for raw materials of fly ash concrete, the improved mix design method for fly ash concrete is proposed. And then it is tested in practical project to verify the workability and feasibility and meanwhile some construction attentions are proposed. The results show that the fly ash can significantly improve the workability of cement concrete. The early strength of fly ash concrete is lower than ordinary concrete, but after 28 days, the compressive strength is similar with ordinary concrete, which provides a reference for design and construction of fly ash concrete.

Abstract: Using visco-elastoplastic-plastic finite element method, the resistant ability to rutting occurring in Heilongjiang province express way has been analyzed. Base on the numerical results, it has been found that the location of rutting occurring mainly existed in middle course, So some modified measurement of middle course to enhance the resistant rutting ability has been proposed. At the same time, A new user Subroutine, which is named dload of ABAQUS, has been employed to simulate the moving vehicle load ,this article has proposed a new method to predict rutting behavior .

Abstract: The daily temperature change of a pavement structure has an important impact on its crack production and propagation. First of all, a one-dimensional transient mathematical model of heat conduction and a heat convection boundary condition that can take solar radiation and ground radiation into account were established according to the characters of the pavement structure and heat conduction. Secondly all the computational formulae were deduced for the above model utilizing SAM. Finally, the hourly temperature field of a typical pavement structure was calculated using ANSYS and SAM respectively. Results show that SAM solutions at different depths are in good line with ANSYS solutions. Therefore, SAM is an easy-programmed, fast and high precise method, and is deserve to be popular. In addition, the daily temperature changes at different depths were discussed, and some suggestions were provided for the thermal crack control and prevention of the structure

Abstract: Based on the monitoring data of pavement performances and traffic volume from the China key projects, the expressways from Shenyang to Shanhaiguan and from Panjin to Haicheng, the effects of asphalt pavement preventive conservation measures utilized in the two expressways and the remaining equivalent standard loads are evaluated. Three models are adopted to predict the pavement performances for the two expressways in six years by the regressing analysis and the reasonable performance prediction models are accomplished through modifying the initial models by the actual monitoring data.

Abstract: Tensional ability of basalt fiber enforced asphalt mixture studied by split tensile test then compare with the normal asphalt mixture. The tensional ability is increasing while increase the basalt fiber percents. The tensional strength increase 3.5%, 7.8%, 3.5% and the failure stiffness modulus increase 15.1%, 40.4%, 11.8% while the added basalt fiber is 0.15%, 0.2%, 0.25%, respectively. The result shows that basalt fiber can enhance the tensional ability of asphalt mixture significantly, and the optimum percents of basalt fiber is 0.2%.

Abstract: 3-D permeability model is set up through image analysis of porous asphalt mixture sample slice by cosmos image technique on the basis of 2-D permeability model of porous asphalt mixture. The result shows that the numerical simulation permeability outcome is consistent with the indoor permeability test outcome. The model can simulate any maximum congregate diameter in different water surface level and the permeability coefficient of any open-graded porous asphalt mixture. The model offers an effective method for the designing of the porous asphalt mixture.