分析了CRCP+ AC复合式路面结构塑性损伤,研究了不同荷载作用条件下结构应力与损伤的空间分布规律.利用正交试验方法,以结构的拉张损伤作为考察指标,对多种复杂的结构因素与环境因素进行了参数敏感性分析,得到了各因素影响规律.根据极差、方差分析结果,区分了变温作用、温度与荷载耦合作用条件下的主要与次要因素,并依据影响效果进行了次序排列.研究结果表明:结构损伤在CRCP面板深度范围内的分布存在差异,导致拉应力的差异化分布;重复行车荷载作用时,随着结构应力软化现象的加剧,结构损伤在初期呈现台阶式上升趋势,后期则增长平稳;根据结构最大塑性主应变的矢量方向可判断结构裂缝平面的法向;综合考量不同荷载作用的分析结果,沥青面层厚度、混凝土的线膨胀系数与面板的支撑情况是影响CRCP结构损伤最为重要的因素.

To provide a theoretic basis for and reference to the material design and crack control research on continuously reinforced concrete pavement (CRCP)and to reveal the causal relationship between the pavement early-age behavior and performance, a computational model by FEM to predict and evaluate the CRCP performance was established. The time effect of concrete material properties, creep characteristics and interface effect between the reinforced concrete and steel were taken into account in the model. Influencing factors, such as concrete coarse aggregate type, variation coefficient of concrete tensile strength, longitudinal reinforcement content, the depth of steel, the bond-slip relationship between the reinforced concrete and steel and the base layer type were mainly analyzed to evaluate their effects on the mean crack spacing, the mean crack width and punchout. The results show that selecting concrete material with low coefficient of thermal expansion, low shrinkage and low modulus of elasticity and ensuring the uniformity of the tensile strength of concrete and reducing the friction coefficient of base materials are all beneficial to obtain a good pavement performance, and the possibility of punchout is less likely to be forecast when the nonlinear bond-slip model or the ultimate slip relationship of the interfaces between the reinforced concrete and steel is taken into account.

The form and distribution pattern of cracks is important for the performance and life of composite pavement constructed with continuous reinforced concrete pavement (CRCP) and asphalt concrete layer (AC) as a surface course. In this study, a 3-D finite element model of the composite pavement is built by using the software ABAQUS, and the damaged plasticity material model for concrete is adopted to describe the mechanics characteristics of the CRC slab. Base on the conclusion from the temperature field analysis, it is found that the improving effect of AC layer becomes apparent when the thickness ratio of AC and CRCP is about 0.15 or above. The structural damage evolution and the crack behavior of the CRC slab subjected to the thermal-mechanical coupling condition are analyzed.

In the study on the CRCP+AC composite pavement,the form and distribution pattern of cracks are two important factors influencing the performance and the lifetime of the pavement.The concrete damaged plasticity material model incorporated in the general purpose finite element software named ABAUQS was adopted to describe the mechanical characteristics of the CRC slab.Combining with the temperature field database drawn from the three-dimensional transient heat transfer analysis,the structural damage under the condition of temperature changing is analyzed.The structural damage evolution and the crack behavior of the CRC slab subjected to the thermal-mechanical coupling condition are further analyzed,which suggests that the role of the asphalt concrete surface is not confined only to the scope of improving the performance of the road,its capacity for improving the stress state of CRCP slab is worthwhile to be affirmed.And the reasonable thickness of AC layer should be designed in consideration of the thermal contraction and damage properties of the CRC slab comprehensively.

A 3D finite element model of a continuously reinforced concrete pavement (CRCP) was developed by using finite element method (FEM) software named ABAQUS. The vehicle load is simplified to be a moving load and has been implemented into a user subroutine VDLOAD. Beam elements and rebar elements are adopted to simulate the steels in CRCP slab. Influence factors, such as longitudinal reinforcement content, driving velocity, traffic load applications, the position of reinforcement and slab thickness, were evaluated to analyze the dynamic stress and displacement of the pavement by the indexes including the stress and strain state and the vertical displacement of CRCP. It is concluded that the dynamic response of CRCP is sensitive to the traffic load; the steels should be placed in the upper position of the CRCP slab; there is little probability that steels in CRCP are subject to yield or fracture under traffic load. Engineers should pay attention to the distress induced by water seepage through the cracks. Increasing the thickness of the slab to improve the pavement performance or to extend the service life of CRCP is not reasonable in the construction practice when the longitudinal reinforcement content is low. The scheme that using thin slab with high longitudinal reinforcement content has more economic advantage and is conducive to the maintenance and reconstruction engineering of CRCP.

The composite pavement of CRCP+AC has often been given credit for its combination of high bearing capacity and desired surface feature like typical flexible pavement has. It has full potential to make the most out of the desired features of both rigid and flexible pavements to make a sound pavement system. In this paper, 3D FEM models of CRCP and CRCP+AC were developed respectively by using FEM software named ABAQUS. The vehicle load is simplified to be a moving load and has been realized through a user subroutine VDLOAD. The differences of the dynamic response between CRCP and CRCP+AC under traffic loading were compared. Influencing factors, including AC thickness, base course type, longitudinal reinforcement content and slab thickness, were evaluated to analyze the dynamic stress and displacement of pavements. The results of analysis can provide theoretic basis and reference for the structural design and construction technique of the CRCP and CRCP+AC.