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Corrosion Resistance of the Metro Tunnel Segments after Repairing of Segment Cracks
(1 Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016; 2 Institute of Architectural Engineering, Yangzhou Polytechnic Institute, Yangzhou 225127; 3 The Communications Planning Surveying and Designing Institute of Shanxi Province, Taiyuan 030012)
Abstract Cracks often occur during manufacturing, construction and operation of metro tunnel segments, and the durability of repaired segments has direct effect on tunnel safety. Simulating different subway tunnel segment crack patterns, using the chloride ion permeation test and sulfate attack test, it studied the erosion resistance of the tunnel segments after repairing various segment cracks with innovative repairing material NR, and a comparison with the commonly used epoxy resin repairing material EC was conducted, with the results show that the concrete resistance to chloride ion penetration increases significantly, the repairing effect of C60 segment is better than that of C50; the repairing effect of segment with polypropylene fiber is better than that of the segment without polypropylene fiber;the repairing effect of PFC50 and C60 segments is better compared with the repairing material EC; after using NR repairing material, the resistance to sulfate corrosion of segment decreases slightly, the decreasing amplitude of bending strength and compressive strength of the repaired C60 segment is smaller compared with that of C50 seg? ment, and the remediation effect of compressive strength is better than that of bending strength; the decreasing am? plitude of compressive strength and bending strength against sulfate corrosion of the segment with polypropylene fi? ber is smaller than the one without polypropylene fiber and the remediation effect of compressive strength is better than that of bending strength; compared with the EC repairing material, the remediation effect of compressive strength against sulfate corrosion of C50 and PFC50 concrete segments is better and the remediation effect of bend? ing strength against sulfate corrosion of three kinds of concrete segments is better.
Abstract：
Cracks often occur during manufacturing, construction and operation of metro tunnel segments, and the durability of repaired segments has direct effect on tunnel safety. Simulating different subway tunnel segment crack patterns, using the chloride ion permeation test and sulfate attack test, it studied the erosion resistance of the tunnel segments after repairing various segment cracks with innovative repairing material NR, and a comparison with the commonly used epoxy resin repairing material EC was conducted, with the results show that the concrete resistance to chloride ion penetration increases significantly, the repairing effect of C60 segment is better than that of C50; the repairing effect of segment with polypropylene fiber is better than that of the segment without polypropylene fiber;the repairing effect of PFC50 and C60 segments is better compared with the repairing material EC; after using NR repairing material, the resistance to sulfate corrosion of segment decreases slightly, the decreasing amplitude of bending strength and compressive strength of the repaired C60 segment is smaller compared with that of C50 seg? ment, and the remediation effect of compressive strength is better than that of bending strength; the decreasing am? plitude of compressive strength and bending strength against sulfate corrosion of the segment with polypropylene fi? ber is smaller than the one without polypropylene fiber and the remediation effect of compressive strength is better than that of bending strength; compared with the EC repairing material, the remediation effect of compressive strength against sulfate corrosion of C50 and PFC50 concrete segments is better and the remediation effect of bend? ing strength against sulfate corrosion of three kinds of concrete segments is better.
2019, Vol. 56 