Crack Propagation Assessment of Time-Dependent Concrete Degradation of Prestressed Concrete Sleepers

Abstract

As prestressed concrete sleepers are continuously exposed to various environmental and loading conditions, it is increasingly crucial to analyse their current and future serviceability performance. In practice, the main cause of cracking in prestressed concrete sleepers is usually induced by impact loads. The most heavily influenced sections are the midspan and rail-seat area of sleepers. This paper investigates the effects of time-dependent concrete strength degradation on the capacity of prestressed concrete sleepers. The factors affecting concrete strength degradation are analysed in order to evaluate the crack behaviour of prestressed concrete sleepers. A finite element modelling approach is developed for prestressed concrete sleepers, which is used to assess the effects of structural behaviour in railway sleepers. The sleeper model has been calibrated and validated. This research firstly discusses time-dependent behaviour using load–crack length responses. It is shown that various cracking modes cause an overall increase in the maximum cracking length as prestressed concrete sleepers age. This paper demonstrates that initial cracking loads and ultimate crack lengths have significant change in first 20 years. After 40 years of service life, the crack resistance of prestressed concrete sleepers becomes very weak which is only 61.32% of the new sleeper. In long term, the initial cracking load keeps reducing, and the crack propagation rate becomes sharp. The presented methodology and results can greatly assist in decision-making for the repair or replacement of prestressed concrete sleepers and aid in the design of new prestressed concrete sleepers considering their future performance.

Engineering, Mechanical and Dynamic Properties of Basalt Fiber Reinforced Concrete

“…Furthermore, a previous study [ 65 ] also shows that the dynamic modulus of elasticity can be correlated to compressive high-strength self-compacting concrete. For example, according to Lu et al [ 66 ] and Li et al [ 67 , 68 , 69 , 70 ], both dynamic and static MOE are relevant to compressive resistance. Therefore, an empirical equation can be settled for estimating, showing that concrete with higher stiffness/MOE usually has a higher compressive performance.…”

Numerical Investigation of Pre-Stressed Reinforced Concrete Railway Sleeper for High-Speed Application

“…Moreover, Figure 35 illustrates the concrete tension damage at the B-B section (under loading point), where the damage can be at its maximum. Figures [36][37][38] show the stress values for each steel bar in the supporting section (C-C section; see Figure 38) and in the loading section (B-B section; see Figures 36 and 37). It can be seen that steel bars had small stress values in the support area and are not yielded.…”

“…• the consideration of changing the strength and elastic moduli of concretes during the lifespan of the sleepers [38]; • investigation of transition zones between significantly different vertical stiffnesses [39,40]; • examination of the crack growing in concrete sleepers [17][18][19][20]23,24,36,38,41]; • investigation of settlements of ballasted tracks with increased sleeper space [42]; • taking into consideration the noise and/or vibration reduction with different sleepers [27]; • development of RC sleepers for a 40 ton axle load [22]; • examination of environmentally friendly production technology [43]; • investigation of fault production of RC sleepers and the possible reasons for it [44]; • development and analysis of RC sleepers of tramway tracks [31]; • analysis of the debonding effect of twin-block slab tracks [45]; • investigation of the 3D modeling of RC sleepers with the consideration of static, dynamic, and impact loads [30,31,33,35,38,[40][41][42]46,47]; • analysis of the features of the stress-strain state of the dual gauge track with a special design of reinforced concrete sleepers with the simultaneous fastening of four rails [48].…”

“…The methods listed below have been applied in the papers: • numerical modeling (finite element method-FEM and/or discrete element method-DEM) [30,31,33,35,38,[40][41][42]46,47 [53,54].…”