This study investigated the structural behaviour of reinforced reactive powder concrete (RPC) beams under service load and fire exposure. The beams were composed of hybrid fibres (50% polypropylene fibres and 50% steel fibres) at different volume fractions relative to nonfibrous-reinforced RPC beams. The bottom and both sides of the beams which were simply supported and loaded with two-point loads were exposed to a controlled fire for 120 min in accordance with ASTM E 119 standard time–temperature curve. The midspan deflection was recorded every 5 min. The experiment also included loading tests on fire-damaged beams after cooling. The nonfibrous-reinforced RPC beams failed during the fire test after 38 min because of the spalling of the reinforcement cover which directly exposed the reinforcing steel to elevated temperatures. By contrast, the beams with hybrid fibres could resist failure during the entire test period. The rate of increase in deflection during fire exposure declined with an increase in hybrid fibre content. Increases in fibre volume fraction from 0.25% to 0.75% and 1.25% decreased the midspan deflection of the reinforced RPC beams by 33% and 36%, respectively. Adding hybrid fibres could considerably improve the residual stiffness of fire-damaged beams.

这项研究调查了钢筋活性粉末混凝土（RPC）梁在使用载荷和火灾下的结构性能。横梁由混合纤维（50％聚丙烯纤维和50％钢纤维）组成，相对于非纤维增强RPC横梁，它们的体积分数不同。根据ASTM E 119标准时间-温度曲线，将简单支撑并承受两点载荷的梁的底部和两侧暴露在受控的火中120分钟。每5分钟记录一次中跨挠度。该实验还包括冷却后对着火的梁的载荷测试。非纤维增强RPC梁在38分钟后的耐火测试中失败，这是因为增强层剥落使增强钢直接暴露在高温下。相比之下，具有混合纤维的梁可以在整个测试期间抵抗破坏。随着混合纤维含量的增加，在火中暴露的挠度增加率下降。纤维体积分数从0.25％增加到0.75％和1.25％，分别使增强RPC梁的中跨挠度降低了33％和36％。添加混合纤维可以显着提高火灾受损梁的残余刚度。