Research on Structure and Material Properties of Asphalt Pavement for Old Concrete Bridge

In order to improve the performance of bridge deck pavement structure, improve the stress state of bridge deck pavement structure layer, reduce the disease of old concrete bridge asphalt pavement, grasp the stress state of bridge deck pavement structure layer and material performance, the asphalt pavement material and pavement structure are optimized. Based on the finite element analysis method, the finite element model of asphalt pavement on cement concrete bridge deck is established. The interlaminar shear stress, interlaminar tensile stress and surface shear stress are selected as the main mechanical control indicators, and the stress variation rule of different thickness and modulus of pavement layer under traffic load is analyzed. The result shows that (1) Shear failure is the main failure form of asphalt pavement on bridge deck, and the thickness of asphalt pavement is the main factor affecting the stress distribution inside the pavement, while the modulus of asphalt pavement material has a little effect on the stress distribution. The proper thickness of asphalt pavement can improve the distribution of internal stress, therefore, 2 kinds of bridge deck pavement structure design schemes, SMA composite structure and AC composite structure are proposed. (2) Based on the indoor test, the high-temperature stability, low-temperature crack resistance, water stability and water permeability of SMA-10, SMA-13 and Ac-13 asphalt mixtures are studied, it is known that all performance indicators of the 3 asphalt mixtures meet the requirements of the design code, but each has its own advantages and disadvantages in different performance. (3) Finally, according to the results of the performance test and the principle of optimizing the material of the bridge deck pavement, under the condition that the performance can meet the requirements of the project, combined with the requirements of the project cost economy and the safety of the bridge structure, a composite structure is recommended as the old concrete bridge deck pavement structure, AC-13 is selected as the old concrete bridge deck pavement upper and lower layer pavement material.