Durable Rail Tie
Emily Herbert – PhD Candidate, Department of Civil and Environmental Engineering, University of Michigan
Victor C. Li – Benjamin Wylie Collegiate Professor, Department of Civil and Environmental Engineering, University of Michigan
Industry: Railroads, Rail Tires
Funding: MTRAC: $100,000, August 2015
Problem: When rail companies started installing prestressed concrete railroad ties, they were expecting them to have a service life of 50 years. Reality shows that these ties last only 10-30 years due to damage caused by cracking of the concrete. The industry has been trying to solve this problem by introducing incremental changes to the design of the concrete ties. However, none of these changes address the true nature of the problem: Concrete is a brittle material and will therefore always be susceptible to cracking damage.
Solution: Our solution is to make rail tires using our ECC (“bendable concrete”) material. This material is currently used in several applications including buildings, bridges, dams, sea walls, etc. ECC is extremely ductile and able to bend under excessive loading, unlike traditional concrete that would fracture and fail under the same conditions. The ductile behavior of ECC allows it to suppress major cracking damage, thus increasing durability and service life.
Market Opportunity: In 2013, about $1.8 billion was spent on rail ties in the US. 650,000 ties were laid as part of expansion projects, while 15.6 million ties were laid as replacements on existing track. Currently, only about 6% of the ties in the US are made of concrete.
Competitive Advantage: It is expected that an ECC rail tie will have a service life of at least 50 years. In addition, due to the ductile nature of ECC, it is possible that ECC ties will not have to be prestressed like traditional concrete ties. The elimination of prestressing means that ECC ties will not only have a longer service life than traditional concrete ties, but may also not require a cost premium since prestressing is an expensive manufacturing process that may be eliminated from the making of an ECC tie.
Key Risks: Technical risks (meeting required performance), IP risks (not being able to obtain patent coverage of innovations), and commercialization risks: finding motivated railroad companies and rail tie manufacturing partners to work with on path to market.