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Author
Rossiter, W. J., Jr. | Nguyen, T. | Martin, J. W. | Byrd, W. E. | Seiler, J. F., Jr. | Lechner, J. A.
Title
Creep-Rupture Tests of Joints Fabricated From Aged EPDM Rubber Membrane Material.
Coporate
National Institute of Standards and Technology, Gaithersburg, MD
Book or Conf
American Chemical Society (ACS). Elastomers in Roofing and Construction Symposium. ACS Rubber Division. Paper 5. October 1991, Detroit, MI, 1-19 p., 1991
Keywords
joints | creep tests | rubber | membranes | adhesives | roofs | roofing (finishes) | cleaning | EPDM roof | peel strength | T-peel joints
Abstract
Am experiment was conducted to assess the creep-rupture performance of joints fabricated from aged EPDM rubber membrane material. The rubber, sampled from a 10-year old roof, was abrasively cleaned with heptane prior to joint formation. Two sets of joints were prepared using a butyl-based pre-formed tape: one designated as "patch" specimens (one strip of cleaned aged rubber adhered to one strip of cleaned new rubber), and the second designated as "new seam" specimens (two strips of cleaned new rubber bonded together). Both sets were stressed in peel under creep conditions to determine their times-to-failure. The mean time-to-failure of the new seam joints was significantly longer than that of the patch joints. The locus of failure of the patch joints (and also new seam joints) was at the interface between the surfaces of the new rubber and the tape. This indicated that cleaning the surface of the aged EPDM rubber by wiping with a cloth soaked with heptane provided a bond with the tape that was more resistant to peel under creep conditions than that of the new cleaned rubber. The mean time-to-failure of the joints fabricated with new cleaned rubber and the pre-formed tape was the same as that previously reported for comparable joints made with solvent-based adhesives. The peel strengths of the patch and new seam specimens were also obtained, and the results are discussed.