Comparison of new LCR and ordinary prestressed concrete railway sleepers with LUR tests

Rail operations today have become more difficult due to increasing operating speeds and decreasing maintenance times. New developed, laminated carbon fiber reinforced polyurethane (L-CFRPU) reinforced concrete railway sleepers (LCR) have the potential to show longer service life in this demanding condition. In this study, a large number of specimens with various reinforcement variations were produced, and improved incremental loading-unloading-reloading (LUR) tests and common one-stage static loading (direct loading) tests were performed. Sleeper deformations, first crack formation loads, and permanent crack width measurements were also recorded during the tests. It is revealed that there are significant differences in peak load capacity, modulus of elasticity, and maximum deformation values between the results of the direct-loading tests and the LUR tests. According to the results, the new LCR sleepers have met the static capacity requirements of standards and also show fewer vertical plastic deformations, which are very important for high-speed railways. Among the samples, sleepers with L-CFRPU surface sanded, and with more spread of L-CFRPU in the concrete section showed better performance than the other sleepers.