Study of Structural Characteristics of Asphalt Overlays on Airport Pavement with Damaged Load Transfer Efficiency of Joints

Author(s):  
Kaifeng Wang ◽  
Kai Wang ◽  
Yunsheng Zhu ◽  
Yunhan Bao ◽  
Zhou Fang

In this paper, the real joint load transfer efficiency of airport pavement is calculated by combining the results of airport pavement deflection detection and ground-penetrating radar detection. Spring elements are used to simulate the actual load transfer efficiency of joints in ABAQUS. The impact of different asphalt overlays on the stress state of the critical point in the pavement is analyzed by the airport cement concrete pavement model. The result shows that adding a thin stress-absorbing layer with fine-graded and low modulus can effectively disperse the load transferred from the asphalt pavement to the cement pavement and the stress concentration at the joint under the asphalt overlay. Compared with airport pavement without a stress-absorbing layer, the tensile stress and shear stress at the critical point in the airport pavement asphalt overlay decreased by 24.62% and 22.49%, respectively. Therefore, the combination of the high-modulus upper layer and low-modulus lower layer can effectively reduce the tensile stress and shear stress at the critical point. In addition, increases in the thickness of the asphalt overlay can effectively improve the stress state at the critical point. When the thickness of the asphalt overlay changed from 13 cm to 21 cm, the maximum tensile and shear stress decreased by 8.82% and 8.92%, respectively. Finally, based on the analysis of the numerical simulation and field test verification, the optimal airport pavement asphalt overlay scheme is proposed.

Author(s):  
Neeraj Buch ◽  
Dan G. Zollinger

The results of an in-depth study of factors that affect dowel looseness in jointed concrete pavements are presented. The laboratory investigation revealed the influence of aggregate type (in relation to oxide content), aggregate texture and shape, bearing stress (dowel diameter and crack width), load magnitude, and number of load cycles on the magnitude of dowel looseness and the subsequent loss in load transfer efficiency across saw-cut joints. A discussion is included on the development of an empirical-mechanistic dowel looseness prediction model based on the experimental results. Results of the sensitivity analysis of the dowel looseness prediction model (using laboratory data) are also presented. An associated scope of this research was to develop a relationship between dowel looseness and loss of load transfer efficiency. The sequential use of the dowel looseness prediction model and its relationship to load transfer efficiency allows the design engineer to predict load transfer characteristics of a joint, based on calculated (or measured) dowel looseness. The framework suggested to predict dowel looseness can then be incorporated into a fault prediction model for doweled joints.


2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xiaolan Liu ◽  
Xianmin Zhang ◽  
Yadong Wang

The evaluation method of load transfer efficiency using falling weight deflectometer is unworkable in remote mountain areas and transportation difficult region. Therefore, a novation method of load transfer efficiency evaluation is proposed using the index of amplitude ratio. Finite element method is applied to study the influence of dowel bar parameters (diameter, length, spacing, and elastic modulus) and pavement structures parameters (thickness and modulus) on load transfer efficiency, frequency, and the ratio of amplitude. Results of finite element model show that the effects of dowel bar and pavement structure parameters on load transfer efficiency and the ratio of amplitude are similar. The load transfer efficiency, frequency, and the ratio of amplitude enhance with the increase of dowel bar diameter, length, and elastic modulus and the decrease of dowel bar spacing. The subgrade modulus has more significant influence on the load transfer efficiency, frequency, and the ratio of amplitude than other pavement parameters. Polynomial function method is utilized to established load transfer mode between deflection-based load transfer efficiency and the ratio of amplitude. The feasibility and reliability of new method is verified by static and dynamic load test. All results are helpful for the development of highway engineering and airport engineering.


2012 ◽  
Vol 178-181 ◽  
pp. 1152-1155 ◽  
Author(s):  
Luo Ke Li ◽  
Yun Liang Li ◽  
Yi Qiu Tan ◽  
Zhong Jun Xue

In a jointed plain concrete pavements, the dowel bar system are used to provide lateral load transfer across transverse joint. Corrosion of commonly used steel dowel in engineering practice reduces their service life and costs considerable maintenance and repair spending for concrete pavements. The objective of this study focus primarily on the performance of none eroded GFRP dowel on LTE( load transfer efficiency) with the help of a three-dimensional finite-element model. The amount of LTE can be obtained directly from comparing the maximum deflection of the concrete slab and the level tensile stress under the concrete slab. According to the finite element results, the larger-diameter GFRP dowel are found to perform the best in this study.


2010 ◽  
Vol 163-167 ◽  
pp. 4599-4603
Author(s):  
Wen Liang Zhu ◽  
Dong Mei Luo ◽  
Ying Long Zhou ◽  
Wen Xue Wang

An improved shear-lag analytical model has been established to study stress transfer in carbon nanotube (CNT) reinforced polymer matrix composites with and without debonding interface. The Poisson’s effect and radial effect of matrix is considered in the model for the first time, and a simplified 2D representative volume element (RVE) is modeled using a four-phase composite composed of matrix, nanotube, bonded, and debonded interfaces in this analysis, and the axial stress for CNT and matrix and interfacial shear stress along the CNT is predicted. The results show that load transfer efficiency in CNT reinforced composites is affected by the debonding length, and the abrupt change of shear stress is existent at the tip of debonding interface.


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