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Date of Publication:2014-01-01

Journal:水力发电学报

Affiliation of Author(s):建设工程学部

Issue:5

Page Number:187-191

ISSN No.:1003-1243

Abstract:Polyurea, as a new environment-friendly impermeable material in the past 20 years, has excellent impermeability and mechanical properties, suitable for dam anti-seepage purpose. An impermeability test of polyurea coated on upstream face of high water head case and a tensile properties test has been completed according to the performance requirements of the impervious layer on the high arch dam. Data of thickness value of this coating layer under different tensile states have been collected, and thickness variation has been obtained by using a data normalization process. The test results show that the coating with thickness greater than 4 mm, can withstand a water leakage pressure of 3 MPa in a crack of no wider than 5 mm. And the tensile failure of polyurea coating is a gradual time process and the appearance of pinprick holes is a sign of such failure featured with an elongation greater than 450% and a tensile strength greater than 22 MPa. During its elongation the coating layer has a decreasing rate of thickness from high to low: its thickness thins to 0.6 times of the initial value at an elongation of 100% and to 0.5 times at an elongation of 300%.

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