2026-09-19T23:57:37Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/30885 2023-07-10 col_2142_5131 col_2142_14770 com_2142_5130 com_2142_3518 com_2142_234

Tutumluer, Erol Boler, Huseyin 2012-05-22T00:13:13Z 2012-05-22T00:13:13Z 2012-05 2012-05-22T00:13:13Z 2012-05 Unbound nature of railroad ballast aggregates causes abrasion and degrada- tion predicaments due to heavy train axle loads. Polyurethane reinforcement of ballast layer is a candidate solution to these problems. However, not many polyurethane reinforcement applications have been studied until the begin- ning of last decade. Therefore, the technology requires considerable research e orts to fully develop. As part of this thesis study research, direct shear testing was undertaken for two di erent railroad ballast aggregates, granite and limestone. Both aggregate materials satis ed the AREMA No. 24 railroad ballast gradation requirements. Although the unbound granite samples showed higher shear strength properties than the unbound limestone samples, polyurethane rein- forcement increased shear strengths of the limestone aggregate samples more than the granite aggregate samples in direct shear (shear box) tests. The granite samples had somewhat of a coarser gradation when compared to the size distribution of the limestone samples. An image aided discrete element modeling approach was used to simulate the shear box tests and calculate number of particle contacts and sample porosities for both the granite and limestone gradations. The simulation results showed that even though the di erences in porosity were only in the order of 2% to 3%, the number of particle contacts for the limestone samples was 50% more than that for the granite samples. In conclusion, number of particle contacts in an assembly of aggregates coated with polyurethane was found to be an important factor contributing to the shear strength properties of chemically bonded ballast aggregate layers. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2012-04-27T15:36:21Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Boler_Huseyin.pdf: 11386223 bytes, checksum: bb6c16640d0dae1ae7b5ba86b0455601 (MD5) Made available in DSpace on 2012-05-22T00:13:13Z (GMT). No. of bitstreams: 2 Boler_Huseyin.pdf: 11386223 bytes, checksum: bb6c16640d0dae1ae7b5ba86b0455601 (MD5) license.txt: 4061 bytes, checksum: ef0347ecd161ee1af6077f11b1535853 (MD5) http://hdl.handle.net/2142/30885 en Copyright 2012 Huseyin Boler Railroad Ballast Shear Strength Polyurethane Reinforcement On the shear strength of polyurethane coated railroad ballast text Civil & Environmental Eng 1251 Civil Engineering 0106 University of Illinois at Urbana-Champaign Thesis M.S. MS:Civil Engineering -UIUC 10KS0106MS