Thermal evolution of CRTS Ⅱ slab track under various environmental temperatures: Experimental study. (28th March 2022)

• Record Type: Journal Article
• Authors: Zhou, Rui; Zhu, Xuan; Ren, Wei-Xin; Zhou, Zhixiang; Yao, Guowen; Ma, Cong; Du, Yanliang
• Is Part Of: Construction & building materials. Volume 325(2022)
• Publication Date: 2022-03-28
• Subjects: CRTS II slab track -- Environmental temperatures -- Thermal performance -- Two constraint conditions -- Environmental testing chamber; CRTS Ⅱ slab track -- Environmental tests -- Thermal performance -- Two bounday conditons; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.126699
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Temperature tests are conducted in a large environmental simulation test system. Two 1:4 scaled models of five CRTS Ⅱ slab tracks with two boundary conditions. Temperature, stress and displacement increase nonlinearly with temperature increase. Temperature, stress and displacement decrease linearly with temperature decrease. The constraint condition accelerate the temperature and temperature gradient. Constraint condition decelerate temperature transfer from track slab to CAM layer. Abstract: The environmental temperature plays an important role in thermal performance of materials and structure in CRTS Ⅱ ballastless slab track under operational condition. In this paper, two 1:4 geometric scaled models of five CRTS Ⅱ slab tracks on a simply-supported box girder under three environmental temperatures rising and dropping cases were conducted in a large-scale environmental simulation testing chamber, respectively. In order to study the effect of constraint conditions on the bond of cement asphalt mortar (CAM), the internal temperature distribution, stress and displacement of two scaled models with constraint and freedom boundary conditions are also compared. Results show that the internal temperatures, longitudinal stresses and displacements of the track structure increase nonlinearly within an increase of the environmental temperature. Accordingly, these same responses decrease linearly within a temperature decrease. Most importantly, when the environmental temperature variation is + 26.5℃, the testing axial force at the two ends of the prototype track structure reaches 2, 849kN, and the relative longitudinal displacement between the track slab and base plate become larger with a decrease of the environmental temperature, especially for the lowest temperature of −20℃. Moreover, fixed constraint condition decelerates the temperature transfer of the track slab to CAM, since it leads to the larger absolute temperatures and stresses of the track structure compared to the free constraint.