00469501

Component

http://onlinepubs.trb.org...trr/1987/1131/1131-003.pdf

https://scholar.google.co...elig&publication_year=1987

In this paper is presented an interpretation of ballast performance test results that uses the information obtained from petrographic analysis of ballast material to help assess the importance of this technique as a means of evaluating ballast. Fourteen ballast materials were used in this study. These were tested in a special ballast box apparatus under differing conditions of equivalent wheel load, material gradation, and number of load cycles. Mill abrasion and ballast cementing tests were also performed on these materials and Los Angeles abrasion values were obtained from the ballast suppliers. Identification of the mineral composition and texture of the ballast material, as well as inherent planes of weakness such as foliation and cleavage, can be accomplished using petrographic analysis. With a few exceptions, petrographic analysis was found to provide a reasonable explanation of the performance of the ballast materials in each of the tests. Performance of ballast in track is a function of field conditions and particle shape and grading as well as of factors identified by petrographic analysis. Thus petrographic analysis is not yet sufficient to predict performance--but neither are commonly used index tests. However, appropriate research involving field observations as well as laboratory testing has the potential to provide a significant improvement in ballast performance prediction using petrographic analysis as an important tool. Such analysis should be performed by a petrographer with experience in railroad applications.

Publication of this paper sponsored by Committee on Railway Maintenance. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01418149

pp 15-25

1987

Transportation Research Record

0309045150

Print

Figures (3) ; References (16) ; Tables (5)

Abrasions; Accelerated tests; Aggregate gradation; Aggregates; Ballast (Railroads); Index tests; Performance evaluations; Petrography; Repeated loads; Wheel loads

Aggregate analysis; Ballast

Geotechnology; Highways; Railroads; I36: Aggregates

TRIS, TRB, ATRI

Jul 31 1988 12:00AM

• COMPONENT IDENTIFICATION AND INVENTORY OF U.S. ARMY RAILROAD TRACKAGE
• EFFECTS OF PARTICLE CHARACTERISTICS ON BEHAVIOR OF GRANULAR MATERIAL
• EVALUATION OF BALLAST MATERIALS USING PETROGRAPHIC CRITERIA
• PERFORMANCE OF LARGE-SCALE MODEL SINGLE TIE-BALLAST SYSTEMS
• PRODUCTION AND TESTING OF BALLAST
• RAILROAD TRACK STRUCTURE PERFORMANCE UNDER WHEEL IMPACT LOADING
• SUBGRADE AND BALLAST REQUIREMENTS FOR 125-TON CARS
• TRACK COMPONENTS FOR 125-TON CARS
• TRACK EVALUATION AND BALLAST PERFORMANCE SPECIFICATIONS
• USE OF GEOSYNTHETICS IN THE DESIGN OF RAILROAD TRACKS