Thermal performance of the solar reflective fluorocarbon coating and its effects on the mechanical behavior of the ballastless track

Li, Yang; Chen, Jinjie; Jiang, Ziqing; Cheng, Guanzhi; Wang, Jianxi; Shi, Xuguo

doi:10.1016/j.conbuildmat.2021.123260

Cited by 23 publications

(5 citation statements)

References 30 publications

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“…15 Under the action of positive and negative temperature gradient, the track slab exhibits arching and concave deformation, respectively. [16][17][18][19] Besides the temperature actions, initial gap damage between the track slab and CA mortar layer will seriously affect the stability of track structure, which is general in practice due to the improper construction operation. [20][21][22][23][24][25][26] Existing studies, as presented above, investigated the interface behaviour considering initial gap damage under the action of overall temperature or temperature gradient independently.…”

Section: Introductionmentioning

confidence: 99%

Interface behaviour analysis of China railway track system Ⅱ slab ballastless track under temperature action and initial gap damage

Wang,

Lu,

Zhang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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The interface damage is considered to be one of the main diseases of China Railway Track System (CRTS) Ⅱ slab ballastless track, which will affect the long-term performance of the track structure and safety operation of high-speed trains. This study aims to reveal the interface damage mechanism between the track slab and the cement asphalt (CA) mortar layer of CRTS Ⅱ slab ballastless track, under different combinations of temperature actions and initial gap damage. A three-dimensional finite element model of CRTS Ⅱ slab ballastless track was established, in which a cohesive constitutive model was incorporated to simulate the interaction behavior of the interface. The interface damage evolution under different temperature actions and initial gap damage was analyzed. The analysis results show that: (1) Overall temperature has a more obvious effect on interface damage compared with temperature gradient, and the greater the overall temperature drops, the lower the decrease of interface damage will be; (2) When initial gap damage occur at the slab end, the growth rate of interface damage under temperature gradient is greater than that under overall temperature; The interface will begin to delaminate when the overall temperature drop reaches −50°C and the gap length becomes greater than one fastener spacing; and (3) When initial gap damage occur at the slab edge, the influence of overall temperature on interface damage is greater than that of temperature gradient; The interface gap damage reaches level II (according to TG/GW 115-2012) at the slab edge under the combination of −50°C and −50°C/m, while the slab center interface is unlikely to be damaged under negative temperature.

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Section: Introductionmentioning

confidence: 99%

Interface behaviour analysis of China railway track system Ⅱ slab ballastless track under temperature action and initial gap damage

Wang,

Lu,

Zhang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…Reflective thermal insulation coatings, as new composite materials that can reduce the absorption coefficient of solar radiation and change the temperature field of a structure, have gradually started to receive attention [9][10][11]. The advantage of a reflective coating is that it can effectively reduce the temperature stress of a track slab and reduce the risk of upper arch deformation [9]; however, its disadvantage is that its use will lead to a sudden drop in the local temperature of the track structure [12], which may have a detrimental effect on the structure. Li et al [9] experimentally verified the feasibility of reflective coating modeling.…”

Section: Introductionmentioning

confidence: 99%

“…The advantage of a reflective coating is that it can effectively reduce the temperature stress of a track slab and reduce the risk of upper arch deformation [9]; however, its disadvantage is that its use will lead to a sudden drop in the local temperature of the track structure [12], which may have a detrimental effect on the structure. Li et al [9] experimentally verified the feasibility of reflective coating modeling. In recent years, scholars have studied the type [13] and thickness [14] of the reflective coating, and the results show that a thin layer of a reflective coating on the surface of a structure can effectively reduce the temperature of the structure.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, Quan explored the effect of coatings and coating position on the transverse and longitudinal temperature as well as the temperature gradient of track slabs. Li et al [9] conducted an experiment on CRTS I double-block ballastless tracks and analyzed the effect of a reflective coating on the temperature field and temperature stress of the track structure under different wind speeds, which provided a reference for the application of reflective coatings in different areas. Liu et al [12] conducted a full-scale experiment on the CRTS II ballastless track structure on bridges with a reflective coating and investigated the longitudinal stress characteristics of the track slab and base plate before and after the application of a reflective coating; the economy of the reflective coating application position was discussed as well.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Reflective Coating on Temperature Field and Temperature Effect of CRTS III Slab Ballastless Tracks on Bridges

Song,

Wu,

Cui

et al. 2023

Materials

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To minimize the adverse effects of high temperatures on the service performance of track structures, research on the application of reflective coatings on track structures is urgently needed. Based on meteorological data and the characteristics of the multi-layer structure of the ballastless track, refined finite element models (FEMs) for the temperature field and temperature effect analysis of the CRTS III slab ballastless track structure on bridges were established. The temperature deformation characteristics and temperature stress distribution of the CRTS III slab ballastless track under natural environmental conditions were investigated. Similarly, the influence of a reflective coating on the structural temperature field and temperature effect was studied. The results showed that the temperature and vertical temperature gradient of the track slab were significantly reduced after the application of the reflective coating. Meanwhile, the thermal deformation and thermal stresses of the track slab and the self-compacting concrete (SCC) layer were minimized. Under high-temperature conditions in summer, the maximum temperature of the track slab decreased from 47.0 °C to 39.6 °C after the application of the reflective coating, and the maximum vertical temperature gradient of the track slab decreased from 61.5 °C/m to 39.1 °C/m after the application of the reflective coating. Under the maximum positive temperature gradient, the peak displacement of the upper arch in the middle of the slab and the peak displacement of the sinking in the slab corner decreased from 0.814 mm and 1.240 mm to 0.441 mm and 0.511 mm, respectively, and the maximum transverse tensile stresses of the track slab reduced from 2.7 MPa to 1.5 MPa as well. In addition, the reflective coating could also inhibit the failure of the interlayer interface effectively. The results of this study can provide a theoretical basis and reference for the application of reflective coatings on ballastless tracks on bridges.

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“…There is serious nonlinear temperature distribution in ballastless track slabs, which can cause temperature-induced issues such as slab warping deformation [4], cracking, and interfacial separation [5][6][7]. The utilization of solar reflective coating on the surface of the aforementioned concrete structures proved to have an obvious cooling effect [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Design and Experimental Evaluation of Composite Magnesium Phosphate Cement-Based Coating with High Cooling Effect

et al. 2022

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The application of surface heat reflective coatings is one of the effective measures to solve the temperature disease of concrete structures in sunlit environments. To achieve strong bonding, high durability, and good cooling characteristics, a novel inorganic reflective thermal insulation coating was prepared using magnesium phosphate cement (MPC) as the binder and reflective matrix, and titanium dioxide and glass beads as the reflective thermal insulation reinforcement functional additives. The optimum ratio of the new reflective thermal insulation coating was preferred through laboratory irradiation test, thermal conductivity test, and spectral reflectance test. The results show that MPC itself was a good reflection cooling material, and the surface and internal temperatures of concrete blocks were reduced by 7.6 °C and 6.6 °C, respectively, after using MPC as the cooling coating. When 2% titanium dioxide was added to MPC, the surface and internal temperatures were further reduced by 6.0 °C and 4.9 °C, respectively. On top of this, the surface and internal temperatures of the concrete were reduced by a further 3.9 °C and 2.2 °C when 8% glass beads were added. The bond strength of the MPCTG coating to the concrete matrix reached 2.1 MPa. Finally, the microscopic characteristics and the reflective thermal insulation mechanism of the MPCTG coating were investigated with the aid of SEM, thermo gravimetric analysis, and XRD analysis. The results show that the MPC in the MPCTG coating was well hydrated, and a large number of hydration products encapsulated the unreacted MgO particles, titanium dioxide, and glass beads, forming a dense whole with high reflection and low thermal conductivity, and the coating effectively prevented the entry of radiant heat. At the same time, the MPCTG coating was thermally stable below 70 °C. The magnesium phosphate cement-based reflective thermal insulation coating developed in this study has potential application prospects in concrete structure cooling coatings.

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Thermal performance of the solar reflective fluorocarbon coating and its effects on the mechanical behavior of the ballastless track

Cited by 23 publications

References 30 publications

Interface behaviour analysis of China railway track system Ⅱ slab ballastless track under temperature action and initial gap damage

Interface behaviour analysis of China railway track system Ⅱ slab ballastless track under temperature action and initial gap damage

Influence of Reflective Coating on Temperature Field and Temperature Effect of CRTS III Slab Ballastless Tracks on Bridges

Design and Experimental Evaluation of Composite Magnesium Phosphate Cement-Based Coating with High Cooling Effect

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