New railway concrete sleeper research about using carbon fiber reinforced polymer rebars with non-prestressed and mono-block process

Over the last two or three decades, the premature failures of railway sleepers have significantly increased the track maintenance and replacement costs. Researchers have previously studied various characteristics and load carrying capacities of railway sleepers, but there is no remarkable solution for the high dynamic impact loads, the resonance of concrete sleepers and the corrosion of steel rebars or prestress tendonds. A sleeper design which do not consider those factors, could damage not only sleepers but also whole railway system. In order to avoid corrosion problems, the use of fibre reinforced polymer bars has emerged as an alternative solution. And also, to prevent resonance vibrations of railway sleepers, non-prestressed reinforcing of sleepers could be a feasibly solution. Among all fibre reinforced polymer bar types, carbon fiber-based systems are the least prone to failure due to fatigue-cyclic loading, exhibit very high tensile strength and low relaxation. The computational analysis of new sleepers was based on Italian guideline (CNR-DT 203/2006). New designed carbon-fibre reinforced sleepers are analyzed with regard to EN 13230, rail seat static positive moment test and compared between the B58 and B70 type prestressed and U3 type non-prestressed concrete sleepers. From the results it was concluded that the concrete sleeper reinforced with carbon fiber reinforced polymer bars shows higher strength than all this concrete sleeper types, moreover the smallest B58 type concrete sleeper cross section areas was used. For about dynamic tests and resonance performance, further works and field measurements needs to be undertaken.