Performance Evaluation of ELASTOTRACK Polyurethane Stabilized Railroad Ballasts
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Date
2017-03
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Addis Ababa University
Abstract
Ballast, the primary loading area in ballasted railroad substructure, is crucial for the
structural support and maintaining of drainage capability. So preserving and enhancing
its performance is not only important but also necessary to prolong the life of railroad
tracks. Though many enhancement measures were recommended by researches over
years, this thesis focuses on stabilizing of ballasts with ELASTOTRACK polyurethane.
ELASTOTRACK polyurethane is a liquid and solventless two components, isocyanate
and resin, cross-linked rigid compact polyurethane which is sprayed on ballast stones and
used to coat them to increase the rigidity of ballasts for the purpose of arresting
permanent deformation of ballast layer as well as preventing infiltration of fouling.
In this thesis, an application using ELASTOTRACK polyurethane particle bonding
technology for stabilizing ballast is evaluated. The results of the tests show that the
average UCS strength of the EPSB specimens (3.16MPa) is greater than that of clean
ballast (1.35MPa) under a confining pressure of 90KPa, which is 57.3% greater. And the
EPSB specimen with full confinement during EP injection had cumulative plastic
stain, , of 0.145% or 92.5% less than clean ballast (1.94%) over many loading cycles.
From evaluation of the elastic deformational behavior of EPSB, the compressive moduli
(i.e., Young's and Resilient Modulus) of EPSB are typically less than clean ballast. As
ballast elastic modulus is reduced from 200MPa to 90MPa in the test, effect on full track
modulus had been analyzed using FEM ABAQUS and results of the model shows that
track modulus was ranged from 30.27-28.94MN/m/m (± 4.4%). Therefore, the EPSB
integration modeled was found to have an inconsequential effect on track elastic
response compared to other key components in the track. Accordingly the LCC of tracks
with ELASTOTRACK polyurethane stabilization have economic advantage of about
43,079EUR/km than clean ballast which increases the benefits expected from rail
transport projects. Use of EPSB stemming from this research presented can serve as an
economically feasible/favorable performance improvement approach. Thus, EP
stabilization is an applicable tool for maintaining track geometry thereby reducing
maintenance cycles associated with plastic deformation of the ballast layer.
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Keywords
Ballast stabilization and performance, Compressive strength, plastic deformation, EPSB, Track modeling, Track modulus