Mechanical property deterioration of the prefabricated concrete slab in mixed passenger and freight railway tracks

Abstract The loading difference of passenger trains and freight trains would influence the damage development of mixed passenger and freight railway tracks. The development of damage, in essence, is the evolution of microfractures and interfaces of the concrete used for the slab track and the deterioration of the concrete’s mechanical properties. In this paper, a batch of concrete specimens were made to test how passenger and freight trains with different wheel loads and at different speeds would influence the mechanical deterioration of concrete used for the prefabricated slab track. Based on damage mechanics, the concrete’s dynamic modulus of elasticity and flexural strength were chosen as two damage variables, and the MTS cyclic loading system was adopted to conduct indoor tests on the specimens in order to analyze the mechanical deterioration rules of the slab track in terms of the two damage variables with passenger and freight railways. The test results indicate that the Miner’s Rule is limited in terms of describing the deterioration process of the prefabricated concrete slab. Also, a greater decrease was seen in the dynamic modulus of elasticity than in the flexural strength. In addition, lower loading frequencies lead to faster damage in the initial phase, while larger stress results in faster damage in the later phases. For example, in the later phases, the test specimen with the stress level of 0.5 is damaged more than 10 times faster than that with a stress level of 0.3, and the test specimen with a stress level of 0.7 and loading frequency of 15 Hz suffers extremely serious material deterioration. Trains running at a lower speed would fasten the damage accumulation at the beginning of the deterioration process, while trains running at a higher speed would aggravate the consequential damage development.