Application of Mastic Asphalt Waterproofing Layer in High-Speed Railway Track in Cold Regions

Abstract

Abstract:Freeze-thaw damage is a typical distress incurred in road and railway engineering in cold regions. Concrete waterproofing layer is commonly used in high-speed railway tracks to prevent the penetration of surface water, however, it cracks easily under thermal stress, especially in cold regions. Recently solutions have been proposed to increase the waterproofing layer's cracking resistance by using asphalt layers. Nonetheless, the use of emulsified asphalt as well as dense-graded asphalt mixture were not effective enough. To improve the effectiveness, in this study, mastic asphalt was designed for application as the waterproofing layer on the subgrade surface of high-speed railway tracks in cold regions. The overall performance of mastic asphalt was preliminarily evaluated by laboratory tests, then a 200-m test section was constructed for field validation in northeastern China as part of a new high-speed railway line, and water content sensors were placed inside the subgrade to monitor the performance of the mastic asphalt waterproofing layer (MAWL). The subsequent field investigation and monitoring data during the two years operation showed that MAWL dramatically outperformed the conventional concrete waterproofing layer in terms of waterproof performance. Plenty of serious cracks were found in the conventional concrete waterproofing layer, but only a limited number of local cracks were observed in MAWL. As a result, MAWL keeps the water content of subgrade at a stable level. In addition, MAWL showed relatively high stability during the two years investigation period, and no obvious deterioration was observed in the test section.

Investigation on Interface Damage between Cement Concrete Base Plate and Asphalt Concrete Waterproofing Layer under Temperature Load in Ballastless Track

“…By setting partly and totally delaminated interface state as the initial conditions, the influence of interface damage on the dynamic response was also analyzed. The main findings can be summarized as follows (1) It is reasonable to obtain the parameters of CZM from the full-scale transverse shear test and apply them in the numerical simulations of interfacial damage evolution under temperature load. (2) For the simulated conditions in this work, the microcracks between CCBP and ACWL were initiated when the temperature rising range was 5.9 • C, and the adjacent layers started to delaminate when the heating range was 19.2 • C. When ∆t exceeded 60 • C, the interface totally delaminated and turned into the slipping contacting state.…”

“…Asphalt concrete has been tentatively used for a full-cross-section waterproofing layer in the substructure of ballastless track in China [1,2]. Asphalt concrete has also been employed as an isolation layer of the high-speed railway foundation, sub-ballast layer of ballast railway, or reinforcement layer of the railway subgrade in Germany, Japan, France, Italy, etc.…”

Experimental Study of Environmental Conditions on In-Situ Engineered Cementitious Composites-Steel Deck Interface

“…Shear and pull-off tests were conducted to evaluate the bond properties [19]. The shear test was divided into single shear and inclined shear tests according to whether there is positive pressure or not.…”

Characterization of Vertical Response of Asphalt Trackbed Concrete in Railway Substructure to External Loads

“…Yusupov et al [10] have also presented a numerical study to examine and predicted the difference in asphalt behaviors at high temperatures, in the example of viscoelastic material assigned to the asphalt concrete trackbed. Liu et al [11] have studied the effect of mastic asphalt waterproofing layer in the railway structure and indicated that the mastic asphalt layer significantly contributes to the trackbed to be waterproof and thus could considerably reduce freeze-thaw damage risk.…”