Studies on Surface Preparation Systems for Polyurea Protective Coating of Beijing-Shanghai High Speed Railway Bridge Concrete Beams

Abstract:

. The comprehensive performance of three kinds of surface preparation systems of polyurea coatings for Beijing-Shanghai High-Speed Railway bridge concrete beams’ protection both in situ and in lab were studied in this paper. The pull-off test and visual inspection were used to determine the adhesion and coverage effect of the bug hole of shot blasted concrete surface. Adhesion tests were conducted both in situ and in lab over a period of 1 year. Five failure models were identified based on the failure mechanisms observed during the tests. It showed that, the adhesion strength of Qtech-112 system increased initially (from 2.7 to 4.8 MPa) and then tended to be stable (about 4.5MPa) both in lab and in situ, E1 and E2 system increased initially (from 1.2 to 1.9 MPa) then decreased to 1.3 MPa under low temperature. The tack free time of Qtech-112 was about 3 hours less than E1 and E2 system. Accordingly, the adhesion and tack-free time of epoxy based system (E1, E2) was very sensitive to application temperature and humidity in jobsite. Polyurethane based system (Qtech-112) have a good adhesion and surface coverage effect to concrete surfaces than epoxy based system under the same ambient condition, it showed an excellent comprehensive performance than epoxy one (E1, E2) both in adhesion and in elimination of pinhole for upcoming polyurea application.

• Periodical: Advanced Materials Research (Volumes 455-456)
• Pages: 765-774
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.455-456.765
• Online since: January 2012
• Authors: Wei Bo Huang, Xu Dong Liu, Zhang Jing, Ping Lu
• Keywords: Adhesion, Beijing-Shanghai High Speed Railway, Coverage Effect, Polyurea, Surface Preparation System

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