191 / 2022-04-30 23:30:27

Investigation on the recycled aggregate from worn ballast in heavy haul railways

Mechanical properties; recycled aggregate; worn ballast; railway engineering

The dirty worn ballast was produced during the ballast cleaning process, which would result in a seriously environmental problem, not only the air pollution but also the waste of a huge amount of the field, which challenges the railway engineering significantly. In China, the transportation capacity of the cargoes is increased more and more rapidly in order to meet the requirement of the economic, which induces the deterioration of the ballast bed in a shorter period subsequently. To make sure of the safety of the transportation, the maintenance of the heavy haul railway was necessary and the frequency of ballast cleaning is enlarged significantly. Moreover, as the “Strong transportation” has pointed out that a sustainable way should be realized in the railway engineering in China, the dirty worn ballast should be recycled in a suitable way in the future.



The investigation of the heavy haul railway in China was conducted, including five main rail net in the north of China. The cleaning distance of the relative lines was cumulated, the cumulated waste from the cleaning process was evaluated based on the daily records. As a result, the total quality of the dirty worn ballast was assessed. The challenge of these worn ballast would be analyzed based on the statistical results.



The compositions of the worn ballast were analyzed. It was found that the worn ballast was polluted due to the coal powder which come from the transportation of the cargos inevitably. According to the seizing of the worn ballast, it was found that it could meet the requirement of both the fine aggregate and coarse aggregate. Some other properties of the worn ballast, such as the composition of the coal was tested, and the crushing strength of the worn ballast was about 2.6.



The recycled aggregate of the worn ballast was conducted. The mechanical properties of the concrete based on the recycled aggregate was compared with the normal materials, as well as crushed aggregate. The slump of the specimens was also conducted. it could be found that the worn ballast could be a suitable choice for the recycled aggregate.