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钢筋增强超高韧性水泥基复合材料(RUHTCC)梁的弯曲性能与配筋率、UHTCC拉压材料性能以及截面尺寸相关。以配筋率为研究的影响因素,理论给出RUHTCC梁3个特征配筋率即最小配筋率、最大弹性配筋率以及最大界限配筋率的计算式。以这3个特征配筋率为边界,理论分析破坏模式从受拉破坏到受压破坏不同情况下梁极限承载力、中性轴高度、曲率、开裂长度以及最外层边缘拉应变的变化规律。提出最优化配筋率的概念,并指出它的大小接近于最大弹性配筋率。进行4种不同配筋率RUHTCC梁和两组RC对比梁的弯曲试验,讨论配筋率对弯曲性能包括承载力、变形、延性以及裂缝开展情况的影响和配筋率对RUHTCC梁较RC梁弯曲性能提高程度的影响。结果表明,对不同配筋率的RUHTCC梁,配筋率越大,极限承载力增加,屈服变形增大,但极限变形减小,延性降低,裂缝宽度的变化不明显。同一配筋率下,RUHTCC可提高RC梁的承载力和延性,在屈服时刻裂缝宽度可控制在0.1mm以内,极大提高了结构的耐久性,但随配筋率的增大,提高程度降低。试验与理论预测进行对比,结果较为吻合。
Bending behavior of reinforced reinforced ultrahigh-toughness cementitious composites (RUHTCC) beams is related to reinforcement ratio, UHTCC tension and compression material properties, and cross-sectional dimensions. Taking the reinforcement ratio as the researching factor, the formula of three characteristic reinforcement ratios, namely the minimum reinforcement ratio, the maximum elastic reinforcement ratio and the maximum limit reinforcement ratio, is given theoretically. With these three characteristics of reinforcement ratio as the boundary, the variation regularity of ultimate bearing capacity, neutral height, curvature, cracking length and outermost edge tensile strain under different failure modes from compression failure to compression failure are theoretically analyzed . The concept of the optimal reinforcement ratio is put forward and its size is approached to the maximum elastic reinforcement ratio. The bending tests of four kinds of RC beams with different reinforcement ratio and two RC beams were carried out to discuss the influence of the reinforcement ratio on the bending performance including the bearing capacity, deformation, ductility and crack initiation and the reinforcement ratio. The bending of the RUHTCC beam was compared with that of the RC beam The impact of increased performance. The results show that, for different RUHTCC beams, the ratio of reinforcement increases, ultimate bearing capacity increases, yield deformation increases, but the ultimate deformation decreases, ductility decreases, and the variation of crack width is not obvious. At the same reinforcement ratio, RUHTCC can improve the bearing capacity and ductility of RC beams. The crack width can be controlled within 0.1mm at the yielding moment, which greatly improves the durability of the structure. However, with the increase of the reinforcement ratio, the improvement degree is reduced . The experimental and theoretical predictions are compared, the results are more consistent.