Preliminary study of concrete with manufactured sand in high-speed railway ballastless track slab

The use of manufactured sand (MS) in concrete has become an inevitable choice in parts regions in China with the increasing depletion of natural river sand (RS), however, the study on the cracking resistance of ballastless track slabs prepared with manufactured sand concrete (MSC) is insufficient due to the complexity of chemical composition and mechanical properties. In this paper, the influence of manufactured sand lithology, that is, Basalt, Tuff, Granite as well as Limestone and stone powder (SP) content, that is, 5%, 10% and 15% on the static mechanical properties of concrete were first investigated. A static load experiment for China Railway Track System (CRTS) Ⅲ ballastless track slab prepared with MS was then conducted. The cracks distribution and damage factor of MSC track slab were analyzed by the finite element analysis method. The bending moment of MSC track slab was further evaluated accounting for train loads, temperature loads and subgrade settlement. Results show that the compressive strength and elastic modulus of MSC are generally higher than those of river sand concrete (RSC), which can be attributed to the sharper edges of MS particles. The static cracking resistance of the MSC track slab meets the required standards when qualified MS is used. However, the SP content in MS exhibits a dual effect on prestressed concrete track slabs and is recommended to be limited to within 10%. This study demonstrates a feasible approach for applying MS in high-speed railway ballastless track slab.