Research on two-dimensional digital characterization of crushed stone aggregates in the SCC filling layer of the CRTS III slab ballastless track

Abstract

Through the actual situation of on-site construction and building, it could be found that the filling quality of the SCC filling layer had a large correlation with the apparent morphology of crushed stone aggregates. This paper investigated the two-dimensional digital characterization of crushed stone aggregates in the SCC filling layer of the CRTS III slab ballastless track through field experiments and compared them with pebble aggregates from three perspectives. Two-dimensional feature data of crushed stone and pebble aggregates in the top view, front view, and left view were obtained using the 3D scanning equipment. The sphericity (or flatness, or circularity) of both crushed stone and pebble aggregates did not directly reflect a uniform pattern of variation in the three views. Pebble aggregates exhibited higher concentration of the sphericity (or flatness, or circularity), while crushed stone aggregates showed more dispersed values. Furthermore, the fractal dimension of crushed stone aggregates was greater than that of pebble aggregates in the corresponding view, with the fractal dimension of crushed stone aggregates tending towards larger values. Regarding the characteristic indices of crushed stone and pebble aggregates, including the sphericity, flatness, and circularity, significant differences were observed between the different characteristic indices. This research provided effective suggestions for the preparation of the SCC with excellent flow characteristics at the construction site.