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Performance of Tape-Bonded Seams of EPDM Membranes: The Effect of Load on Peel-Creep.


pdf icon Performance of Tape-Bonded Seams of EPDM Membranes: The Effect of Load on Peel-Creep. (1440 K)
Rossiter, W. J., Jr.; Vangel, M. G.; Kraft, K. M.; Embree, E. J.

Challenges of the 21st Century. Roofing Technology, Fourth (4th) International Symposium. Proceedings. First (1st) Edition. U.S. National Institute of Standards and Technology, U.S. National Roofing Contractors Association, Canadian Roofing Contractors Association, National Research Council of Canada, International Waterproofing Association, CIB, RILEM. September 17-19, 1997, Gaithersburg, MD, 1-13 pp, 1997.

Keywords:

roofs; adhesive tapes; adhesive testing; bonding; creep rupture; EPDM roofing membranes; microscopy; seams; time to failure

Abstract:

A study was conducted to compare the peel creep-rupture response (i.e., time-to-failure or TTF) of tape-bonded and liquid-adhesive-bonded seams of EPDM (ethylene-propylene-diene terpolymer) roof membranes. Two commercial tape systems (i.e., tape and primer) and one liquid adhesive were applied to well-cleaned EPDM rubber in the NIST laboratories. The creep-rupture experiments were conducted at 23 deg C (73 deg F) and 40 percent to 45 percent relative humidity under peel loads ranging from 3.1 N to 24.9 N (0.7 lbf to 5.6 lfb). For each adhesive system, the data were found to be fitted well by the model. The conclusion was that the tape-bonded sample sets had mean times-to-failure that were, in most cases, comparable to or greater than those of the liquid-adhesive-bonded sample sets. In addition, the tape-bonded specimens provided time-to-failure results that were reproducible between replicate sets. In a related experiment, the creep-rupture response of six sets of tape-bonded specimens prepared in the laboratories of EPDM membrane manufacturers was compared with that of NIST-prepared tape-bonded sample sets. Five of six manufacturer-prepared samples sets had similar, or longer, times-to-failure than the NIST-prepared sample sets at low creep loads. In the case where the manufacturer-prepared sample sets had a statistically significant shorter time-to-failure than the NIST-prepared sample sets, the difference was not practically important.