Study of granulometric ranges in the behavior and useful life of railway ballast using dynamic testing equipment

Abstract

The particle size range directly influences the useful life of the ballast layer when subjected to loads generated by railway traffic. However, in Brazil, we only have two particle size ranges to be used. Those recommended by Brazilian regulatory bodies are quite uniform, and publications referring to more efficient mechanical behavior express the need for a well-graded lane, different from the lanes normally used on Brazilian roads. Therefore, the influence of the particle size of the ballast used on railways was the object of study, with the aim of verifying the mechanical behavior and its influence on the useful life of the track, mitigating the generation of fines and maintaining drainage efficiency. For this, two granulometric ranges were chosen: Range 3 of AREMA (Range A of the Brazilian Association of Technical Standards - ABNT) and Australian Range 50. For this study, using dynamic equipment that simulates railway traffic, two different granulometric ranges were analyzed, and with the data found on Cc, CNU, fineness modulus and maximum diameter, a better graduated particle size range and a particle size distribution that fit into this new range were proposed to be used, in order to improve the overlap between the grains, reducing their breakage , improving deformability, without compromising permeability.