An experimental study on the characteristics of polyurethane-mixed coarse aggregates by large-scale triaxial test

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>The two main functions of ballast are train-load distribution and track-water drainage. Repeated train passage subjects ballast aggregates to abrasion and, eventually, breakage. Mixing of bonding materials such as polyurethane into aggregates can effectively mitigate ballast degradation. In the present study, large-scale triaxial tests were carried out to investigate the characteristics of polyurethane-mixed ballast materials. The stiffness and strength of the materials could be predicted in terms of the polyurethane contents, and the linear relationships could be established. According to those relationships, the performance of polyurethane-mixed aggregates as enhanced railway ballast materials can be simply but reasonably estimated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This paper focuses on the behavior of ballast aggregates induced by train loading. To improve performance of the ballast, polyurethane is added. The moduli and strength are investigated according to content of polyurethane. </LI> <LI> A large scale triaxial testing equipment was applied to evaluate the behavior of ballast accurately. The large triaxial tests lead to the correlation between polyurethane content and stiffness of polyurethane mixed ballast. The large scale triaxial tests provide with predictive model for strength as well. </LI> <LI> These simple models are believed to help design the ballast with polyurethane without expensive and cumbersome testing. </LI> </UL> </P>