Interfacial performance of slab track with gradient polymer-modified self-compacting concrete

Abstract

Excellent bonding and a moderate elastic modulus of self-compacting concrete (SCC) are crucial for reducing the interfacial damage of slab track and meanwhile avoiding a sharp decrease in elastic modulus. In this study, a gradient distribution of polymer in SCC was introduced to slab tracks for the first time, ensuring a significant enhancement of interfacial performance. An interface damage model of slab track was established to investigate the influences of mechanical parameters of gradient polymer-modified SCC and interfacial cohesive parameters on the interfacial displacement, stress and damage initiation. It is expected to improve the interfacial performance of slab tracks and bring new insights into the development of long-service-life slab tracks. Results indicated that the gradient elastic modulus effectively coordinated interface deformation and reduced the interfacial displacement and stress, minimizing the initiation of interfacial damage. The gradient Poisson's ratio had little influence on the interfacial damage. Moreover, the local accumulation of polymer on the surface of SCC significantly reduced both the interfacial normal and tangential stiffness, thereby lowering the interfacial stress. Additionally, the accumulation of polymers (≤ 20 %) enhanced the tangential cohesive strength of the interface between SCC and track slab. These effects led to a noticeable reduction in the damage initiation factor of the interface in the slab track.