Research chemist, Oxford Management and Research Center, Middlebury, Conn.
Pages: 9 Published: Jan 1976
A laboratory test method, based on the “toughness” value of the material, has been developed to distinguish between high- and low-performance rubberized asphalt membranes used in inverted (protected-membrane) roofing systems.
Rubberized asphalts with a high toughness level have been shown, under laboratory conditions, to be capable of bridging structural cracks in concrete decks at temperatures as low as -18°C (0°F). When the temperature is raised, the membrane remains as an undeformed continuous film. On the other hand, membranes with a lower toughness level were shown to fail at high strain rates, while at lower strain rates they sag irreversibly after such a temperature cycle. During application of the membrane, such temperatures may be experienced for short periods of time before the insulation is placed on top of the membrane or before the building is heated.
Field experience in waterproofing applications, including bridge decks, underground parking garages, and plazas as well as roofs, has shown that the toughness level, combined with other properties such as low temperature flexibility, resistance to flow, and penetration, correlate well with actual performance.
roofing, bituminous materials, asphalts, toughness, waterproofing, tests
Paper ID: STP27787S