Adhesion of spray-applied fire-resistive materials (SFRMs) to steel structures is critical in enabling the capacity of a building to remain functional for a specific length of time during a fire for life safety and fire department assess. Empirical tests such as ASTM E736 have been widely adopted by the industry in an effort to ensure sufficient bonding between SFRMs and steel structures. ASTM E736 assesses the adhesion performance of SFRM by using ultimate tensile strength, a failure parameter that depends on the test geometry and has very limited use for predicting failure in other geometries and conditions. These limitations have led to many criticisms and produced an urgent need for a scientifically meaningful adhesion test method. In this paper, we proposed to a new test method which would generate more fundamental information, i.e. a result that is independent of test geometry and therefore has predictive capability. The work here utilizes a fracture mechanics-approach with an energy-based failure criterion to characterize the adhesion between SFRMs and steel structures with a fracture energy, . The theoretical basis of this test method is validated by an experimental compliance tests. The dependence of on a wide range of test variables such as specimen width, substrate type, SFRM formulation, and test rate were examined. A comparison between this new test method and the current widely used strength-based test method was also presented.
Citation: Fire and Materials
Pub Type: Journals
Adhesion, cantilever beam, fracture-mechanics, spray-applied fire resistive materials, test method.