Browsing by Author "Aregawi, Gebru"
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Item Improvement of Ballast Material with Addition of Waste Tire Rubber(Addis Ababa University, 2020-11) Aregawi, Gebru; Henok, Fikre (PhD)Railway ballasted track is the most common form of construction used in railway transportation due to a number of reasons. But a lot of problems are associated with a ballasted track. The excessive deformations and degradations of the ballast, unacceptable differential settlement of track, liquefaction of underlying soft subgrade soils etc. are some of them. The traffic flow of rail is increasing every year, due to increased goods and passenger traffic. This in turn, has led to a more rapid degradation of the railway track and high maintenance cost. Degradation will affect the comfort and safety of the traffic also. Under good track conditions, where there is supportive sub ballast and a stable subgrade, ballast is the main source of induced track settlement. To improve ballast material with addition of waste tire rubber physical strength and shear strength tests were performed. The effect of ballast flying was also studied and it safe velocities have been found within the limits of the considered ranges of rubber percentages used in the research. Researches have been carried out to develop new materials with the aim of increasing the service life of the track. This thesis identifies the use of waste tire rubber as an elastic aggregate, and analyses its effect on strength, degradation and settlement characteristics of ballast.