钢筋活性粉末混凝土简支梁受弯力学性能试验与计算

活性粉末混凝土(RPC)与普通混凝土(OC)相比,具有超高的强度、高韧性和优异的耐久性,其构件承载力与刚度计算方法必然不同于普通混凝土构件。该文对4根钢筋活性粉末混凝土简支梁开展受弯性能足尺试验,获得了梁的开裂弯矩、极限弯矩及荷载-跨中位移曲线,揭示了RPC简支梁受弯变形特征与破坏模式,推导了钢筋RPC简支梁的开裂弯矩与正截面受弯承载力计算公式。结果表明:钢纤维RPC极限压应变为4394με~5200με,开裂应变为690με~820με,均远大于普通混凝土;由于添加了钢纤维,公式推导时必须考虑RPC拉区拉应力的影响,推导所得开裂弯矩、正截面受弯承载力及刚度公式计算值与试验值吻合较好,计算公式具有较高的精度,可用于钢筋RPC梁的设计计算。

EXPERIMENTAL AND CALCULATION OF FLEXURALMECHANICAL PROPERTIES OF REINFORCED REACTIVE POWDER CONCRETE SIMPLY SUPPORTED BEAMS

Reactive powder concrete (RPC) has superior strength, high toughness and excellent durability compared with ordinary concrete (OC). The calculation method of the strength and stiffness of components of RPC is inevitably different from ordinary concrete components. A full-scale test on the bending performance of four reinforced RPC simply supported beams is conducted. The cracking moment, ultimate bending moment and mid-span load-deformation curve of the beam are obtained. The bending deformation characteristics and failure modes of RPC simply supported beams are revealed, and the calculation formulas for the cracking moment and the bending strength of the RPC simply supported beams are derived. The ultimate compressive strain of steel fiber reinforced RPC is 4394 με~5200 με, and the cracking strain is 690 με~820 με, which are much larger than those of OC. Due to the addition of steel fibers, the influence of the tensile stress of the RPC tension zone must be considered. The derived cracking moment, the normal section bending capacity and the calculated value of the stiffness are in good agreement with the experimental values. The calculation formula has high precision and can be used for the design calculation of reinforced RPC beams.