Spray-applied fire-resistive materials (SFRM) is one of the most widely used passive fire protection material for steel structures in North America. However, SFRM is inherently brittle and tends to dislodge or delaminate under extreme loading conditions (earthquakes or impacts) and even normal service load. Such loss of fire protection material puts the steel structure in great danger in subsequent fires. To address this concern, a new type of ductile spray-applied fire-resistive material, namely spray-applied fire-resistive engineered cementitious composite (SFR-ECC), has been developed recently as a durable alternative to conventional SFRM. SFR-ECC exhibits a ductile strain-hardening behavior with tensile strength, tensile ductility and interfacial adhesion (to steel) of 1-2 orders of magnitude higher than those of conventional SFRM under static loads. In the present paper, the behavior of SFR-ECC under high rate loading was experimentally studied. SFR-ECC maintains desired tensile performance under high rate loading, ensuring the performance of such material under impact or earthquake loads. Low velocity impact tests were also conducted on SFR-ECC protected steel beam and panel. SFR-ECC protected steel system showed much higher impact resistance than conventional SFRM protected ones. The integrity and functionality of SFR-ECC were well preserved after multiple impacts while conventional SFRM experienced catastrophic failure. This experimental study further demonstrated the advantages of SFR-ECC over conventional SFRM under severe loading conditions, which is critical for the fire safety of steel structures under multi-hazards.
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