Freeze-Thaw Performance of Precast, Prestressed Concrete Railroad Crossties
Daniel Castaneda, a Ph.D. Candidate in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign, presented his seminar on March 31, titled "Freeze-Thaw Performance of Precast, Prestressed Concrete Railroad Crossties."
Daniel Ivan Castaneda is a Ph.D. Candidate in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign. His research seeks to understand the consequence of design, handling, and placement of fresh concrete and cementitious materials as they relate to the long-term durability of civil infrastructure. His work includes examining the loss of air-entrainment in extensively vibrated fresh concrete with adapted rheology; investigating bond of repair materials in non-ideal placement conditions; thoughtful selection of sorptive aggregates to control diffusion processes in alternative, sustainable binder systems; development of a field-test to measure residual stresses in plain concrete pavements and structures; and instrumentation of recycled aggregate pavements. Daniel is originally from southern California and attended the University of California, Berkeley, where he completed his B.S. in 2008. After graduating from Berkeley, he worked as a systems analyst in Silicon Valley where he drafted analytical solutions for the Federal Aviation Administration regarding aircraft excursions out of protected Class B airspace. Daniel is an associate member of the American Concrete Institute (ACI Committee 236) and the Cements Division of the American Ceramic Society (ACerS).
Concrete used in critical infrastructure is susceptible to structural and material damage, including freeze-thaw damage because of its exposure to wet and cold climates. In railroad lines, concrete crossties are now being used because of their advantages in sustaining higher traffic loads; however, premature damage has been observed at the rail seat area where the crosstie is fastened to the steel rail line. The Federal Railroad Administration is motivated to minimize premature crosstie damage such that maintenance costs are reduced and dangerous derailments do not occur, particularly as the United States moves toward implementing regional high speed passenger rail networks. A three-year study on the freeze-thaw durability of concrete railroad crossties was recently completed by the University of Illinois in partnership with Kansas State University. The wide-ranging study focused on the manufacturing of precast, prestressed concrete railroad crossties and their performance against freeze-thaw damage. New insight was gained about how consolidating vibration affects the fluid properties of concrete that, in turn, leads to the undesirable loss of entrained air bubbles exiting the fresh material system. This loss of entrained air makes hardened concrete more susceptible to freeze-thaw damage, so a field study instrumented concrete crossties was also conducted to better understand the extent of critical moisture saturation and freezing temperatures in field conditions. Models are adapted from fluid mechanics and pavement engineering in order to create a framework to better understand the freeze-thaw susceptibility of critical concrete infrastructure, and justify recommendations for precast concrete manufacturers that can improve the quality control of concrete crossties.