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Repeatability of Minimum and Maximum Density Testing on Clean and Fouled Ballast
Ballast material is a critical part of the safety of railways, such as padding tracks to prevent dynamic vibrations from causing trains to derail. The effectiveness of this material is closely tied to the percentage of fouling that is intermixed with the material. Generally, ballast is placed as compact as practical, but overtime, fouling of the ballast changes the composition of the placed material. Relative density could provide insight into the relative compactness and strength of the material. Unfortunately, the results of minimum or maximum density tests are not well documented in the existing literature. Although ASTM D4254 and D4253 do provide guidelines for minimum and maximum density testing of large particle diameters, there is minimal discussion in the literature regarding the anticipated error when testing with ballast and fouling. Tests to attempt to characterize this behavior, minimum and maximum density tests were run using Connecticut Granite ballast with granite stone dust used as a fouling material. The samples contained fouling at intervals of 0, 15, 30, 45, and 60% by mass and were placed in a 12-inch interior diameter cylinder mold in accordance with the ASTM standards. For each fouling condition, two operators each conducted 10 minimum density and 5 maximum density tests for a total of 100 minimum density tests and 50 maximum density tests. The effect of fouling, density, and operator, on the repeatability of the tests on ballast, is discussed.
Repeatability of Minimum and Maximum Density Testing on Clean and Fouled Ballast
Ballast material is a critical part of the safety of railways, such as padding tracks to prevent dynamic vibrations from causing trains to derail. The effectiveness of this material is closely tied to the percentage of fouling that is intermixed with the material. Generally, ballast is placed as compact as practical, but overtime, fouling of the ballast changes the composition of the placed material. Relative density could provide insight into the relative compactness and strength of the material. Unfortunately, the results of minimum or maximum density tests are not well documented in the existing literature. Although ASTM D4254 and D4253 do provide guidelines for minimum and maximum density testing of large particle diameters, there is minimal discussion in the literature regarding the anticipated error when testing with ballast and fouling. Tests to attempt to characterize this behavior, minimum and maximum density tests were run using Connecticut Granite ballast with granite stone dust used as a fouling material. The samples contained fouling at intervals of 0, 15, 30, 45, and 60% by mass and were placed in a 12-inch interior diameter cylinder mold in accordance with the ASTM standards. For each fouling condition, two operators each conducted 10 minimum density and 5 maximum density tests for a total of 100 minimum density tests and 50 maximum density tests. The effect of fouling, density, and operator, on the repeatability of the tests on ballast, is discussed.
Repeatability of Minimum and Maximum Density Testing on Clean and Fouled Ballast
Lecture Notes in Civil Engineering
Tutumluer, Erol (editor) / Nazarian, Soheil (editor) / Al-Qadi, Imad (editor) / Qamhia, Issam I.A. (editor) / Jones, M. W. (author) / Akey, E. K. (author) / Ho, C. L. (author) / Rubin, A. J. (author)
2021-08-05
11 pages
Article/Chapter (Book)
Electronic Resource
English
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