DUCTILE SPRAY-APPLIED FIRE-RESISTIVE MATERIAL FOR ENHANCED FIRE SAFETY

摘要

Spray-applied fire-resistive material (SFRM) is one of the most widely used passive fire protection material in North America.However, SFRM is inherently brittle and tends to dislodge or delaminate under extreme loading conditions (earthquakes or impacts) and even under normal service conditions such as impacts caused by maintenance work.Such loss of fire protection material puts the steel structure in great danger under fire loading, especially under multi hazards (post-earthquake or post-impact fires).As an alternative to conventional brittle cementitious material, engineered cementitious composites (ECC) is a family of high performance fiber reinforced cementitious composites.ECC typically exhibits strain hardening behavior with very high tensile ductility (3-5％) under loading.In this paper, a new spray-applied fire-resistive material that combines the desirable thermal insulation property, ease of construction (facilitated by sprayability), light-weightness of SFRM and the enhanced ductility of ECC is developed as an alternative material to current SFRM.The newly developed spray-applied fire-resistive ECC (SFR-ECC) exhibits density as low as 550 kg/m3 yet with tensile strength of 1.1 MPa and tensile strain capacity of 3.0％ significantly higher than those of conventional SFRM with tensile strength of less than 0.1MPa and no inelastic tensile strain.The thermal conductivity and sprayability of SFR-ECC are measured to be comparable to conventional SFRM, which ensures the proper functionality of SFR-ECC.SFR-ECC with enhanced mechanical performance is expected to improve the overall fire safety of steel structure under both service and extreme loads.