Ryan G. Kernes, Amogh A. Shurpali, J. Riley Edwards, Marcus S. Dersch, David A. Lange, and...
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Ryan G. Kernes, Amogh A. Shurpali, J. Riley Edwards, Marcus S. Dersch, David A. Lange, and Christopher P.L. Barkan International Concrete Crosstie & Fastening System Symposium Urbana, IL 6-8 June 2012 Investigation of the Mechanics of Rail Seat Deterioration (RSD) and Methods to Improve the Abrasion Resistance of Concrete Sleepers
Ryan G. Kernes, Amogh A. Shurpali, J. Riley Edwards, Marcus S. Dersch, David A. Lange, and Christopher P.L. Barkan International Concrete Crosstie & Fastening
Ryan G. Kernes, Amogh A. Shurpali, J. Riley Edwards, Marcus S.
Dersch, David A. Lange, and Christopher P.L. Barkan International
Concrete Crosstie & Fastening System Symposium Urbana, IL 6-8
June 2012 Investigation of the Mechanics of Rail Seat Deterioration
(RSD) and Methods to Improve the Abrasion Resistance of Concrete
Sleepers
Slide 2
Slide 2 Investigating Rail Seat Deterioration Outline
Objectives Rail seat deterioration (RSD) background Large scale
abrasion test Evaluation of frictional properties Small scale
abrasion resistance test Results Conclusions and future work
Slide 3
Slide 3 Investigating Rail Seat Deterioration Objectives
Understand the mechanics of the most critical failure modes
Investigate parameters that affect abrasion mechanism Characterize
frictional forces between rail seat and rail pad Propose methods of
mitigating the critical failure modes Quantify abrasion resistance
of various concrete mix designs, curing conditions, and surface
treatments
Slide 4
Slide 4 Investigating Rail Seat Deterioration Rail Seat
Deterioration (RSD) Degradation of concrete material under rail and
pad Increases maintenance costs Shortens service life of the
concrete crosstie Leads to track geometry defects Feasible
mechanisms: Abrasion Crushing Freeze-thaw damage Hydro-abrasive
erosion Hydraulic pressure cracking
Slide 5
Slide 5 Investigating Rail Seat Deterioration Abrasion
Mechanism of RSD Abrasion is a progressive failure mechanism that
occurs when: Frictional forces act between two surfaces in contact
Relative movement occurs between the surfaces Harder surface cuts
or ploughs into softer surface Progression of abrasion at the rail
seat 1.Cyclic motion of rail base induces shear forces 2.Shear
forces overcome static friction 3.Pad slips relative to concrete
4.Strain is imparted on concrete matrix Abrasion involves 3-body
wear: two interacting surfaces (rail pad and rail seat) and
abrasive slurry (water and fines)
Slide 6
Slide 6 Investigating Rail Seat Deterioration Large Scale
Abrasion Resistance Test Experimental Setup Vertical Actuator
Horizontal Actuator Abrasion Pad Concrete Specimen
Slide 7
Slide 7 Investigating Rail Seat Deterioration Large Scale
Abrasion Resistance Test Results Consistently able to cause
deterioration of concrete due to abrasion Concrete deterioration
initiates near pad edges and propagates inward Heat build up in pad
materials at local contact points leads to softening and adhesion
to concrete surface Difficulty in correlating severity of abrasion
to input variables Contact angle and pressure distribution
Heterogeneity of concrete surface
Slide 8
Slide 8 Investigating Rail Seat Deterioration Experimental
Evaluation of Friction Magnitude of static frictional force is
directly related to the normal force between the two bodies by the
coefficient of friction () Experimental frictional coefficient
measured during test calculated by: = ||/ where F is the force
required to initiate lateral sliding under vertical normal load P
400 loading cycles to simulate single unit train pass 5,000 pound
normal vertical load (420 psi), 1/8 lateral displacement, 3
cycles/second, no abrasive fines or water added
Slide 9
Slide 9 Investigating Rail Seat Deterioration Mean Coefficient
of Friction per Loading Cycle Polyurethane Nylon 6/6
Slide 10
Slide 10 Investigating Rail Seat Deterioration Effect of
Environmental Conditions on Nylon 6/6
Slide 11
Slide 11 Investigating Rail Seat Deterioration Effect of
Environmental Conditions on Concrete Abrasion Polished surface with
no sand Abrasion initiated with sand
Slide 12
Slide 12 Investigating Rail Seat Deterioration Effect of
Increasing Normal Load on Nylon 6/6 5 kips 3 kips 10 kips
Slide 13
Slide 13 Investigating Rail Seat Deterioration Small Scale
Abrasion Resistance Test (SSART): Test Setup In general, similar to
other standard abrasion tests Consists of powered rotating steel
wheel with 3 lapping rings Lapping rings permitted to rotate about
their own axis Vertical load applied using the dead weights
Abrasive sand and water dispensed during testing
Slide 14
Slide 14 Investigating Rail Seat Deterioration Test Protocol
Each test can evaluate 3 specimens Multiple tests are run to
evaluate more than 3 specimens Specimen dimensions: 4 inch
(diameter),1 inch (thickness) Duration: 120 minutes Wear depth
measurements taken every 20 minutes Speed: 60 revolutions per
minute Abrasive fine: Ottawa 20-30 sand Before After
Slide 16 Investigating Rail Seat Deterioration Effect of
Mineral Admixtures
Slide 17
Slide 17 Investigating Rail Seat Deterioration Effect of Fiber
Reinforcement
Slide 18
Slide 18 Investigating Rail Seat Deterioration Effect of Curing
Conditions
Slide 19
Slide 19 Investigating Rail Seat Deterioration Comparison of
Techniques to Increase Abrasion Resistance
Slide 20
Slide 20 Investigating Rail Seat Deterioration Additional Tests
Conducted Objective: to obtain specimens batched by industry
concrete crosstie suppliers Silica fume and epoxy coated specimens
tested Saw-cut surface of control specimens considered analogous to
ground surface and tested GrindingEpoxy coating
Slide 21
Slide 21 Investigating Rail Seat Deterioration Effect of
Surface Treatments
Slide 22
Slide 22 Investigating Rail Seat Deterioration Conclusions
Large scale testing: Confirmation of abrasion as a feasible RSD
mechanism Frictional coefficient is affected by temperature, water,
sand, normal force SSART: Successfully compared 13 approaches to
improving abrasion resistance of rail seat through material
improvements Improve abrasion resistance of concrete with: Optimal
amounts of fly ash Proper curing condition Addition of steel fibers
Grinding cement paste
Slide 23
Slide 23 Investigating Rail Seat Deterioration Future Work
Determining the optimal frictional properties at each interface of
multi-layer rail pads (top, bottom, and between layers) could:
Reduce movement at critical interfaces Influence load path and
location of slip Delay the onset of abrasive wear and extend rail
seat life Extend to other fastening system components SSART:
Perform image analysis to characterize the role of coarse aggregate
in abrasion resistance Study the effect of air entrainment and
quality of aggregates on abrasion resistance of rail seat Use of
Statistical Analysis Software (SAS) to model abrasive wear of
concrete specimens Optimize concrete mix design and surface
treatments to mitigate abrasion
Slide 24
Slide 24 Investigating Rail Seat Deterioration Acknowledgements
Funding for this research has been provided by Association of
American Railroads Technology Scanning Program NEXTRANS Region V
Transportation Center Eisenhower Graduate Fellowship For providing
direction, advice, and resources: Amsted Rail - Amsted RPS: Jose
Mediavilla, Dave Bowman, Brent Wilson, BNSF Railway: John Bosshart,
Tom Brueske, Hank Lees AREMA Committee 30: Winfred Boesterling,
Pelle Duong, Kevin Hicks, Tim Johns, Steve Mattson, Jim Parsley,
Michael Steidl, Fabian Weber, John Zeman TTCI: Dave Davis, Richard
Reiff Pandrol Track Systems: Bob Coats, Scott Tripple UIUC: Tim
Prunkard, Mauricio Gutierrez, Don Marrow, Darold Marrow For
assisting with the research and lab work: Josh Brickman, Ryan
Feeney, Kris Gustafson, Steven Jastrzebski, Andrew Kimmle, Calvin
Nutt, Chris Rapp, Amogh Shurpali, Emily Van Dam, Michael Wnek
Slide 25
Slide 25 Investigating Rail Seat Deterioration Questions Ryan
Kernes Research Engineer Rail Transportation and Engineering Center
- RailTEC email: [email protected] Amogh A. Shurpali Graduate
Research Assistant Rail Transportation and Engineering Center -
RailTEC email: [email protected]