Evaluation on mechanical behavior of asphalt concrete trackbed with slab panel using full-scale static and dynamic load test

Abstract

In this study, a full-scale model of a railway track structure using an asphalt concrete trackbed with concrete slab panel (ACTSP) is developed. Slab panels are very important to develop asphalt concrete (AC) track system for minimizing the roadbed pressure due to the trainload and reducing the plastic deformation of the AC. The purpose of this study is to analyze the performance of the subgrade and the AC trackbed under different AC layer concepts. Static and dynamic loads were applied to the whole track system by using the Railway Loading System (RLS). Based on the data acquisition and instrument systems, the displacement of the rail/sleeper, the strain at the bottom of the asphalt concrete, and the pressure characteristics of each subgrade was measured. The pressure distribution efficiency along the track system was also investigated. Based on the full-scale test results, the application of asphalt concrete trackbed is very promising since this technology will noticeably mitigate the impact of pressure on the track system from the trainload. The effectiveness is more prominent in railway structures having an AC trackbed thickness of around 35 cm. In this condition, the dynamic train load results reveal that plastic deformation and tensile strain of rail and panel can substantially be reduced up to 20 and 50%, respectively, compared to the condition of 20 cm trackbed thickness. The results also indicate that the pressure distribution along the panel is improved by using a thicker AC layer roadbed concept. Overall, the findings in the research suggest that asphalt concrete trackbed with slab panel is a novel technology that will reinforce the durability of track components and prolong the service life of railway track structure.