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针对应变硬化水泥基复合材料(SHCC)存在弹性模量和强度较低等不足,采取致密化方法对普通SHCC进行改进,研究出适用于RC梁加固的致密应变硬化水泥基复合材料(DSHCC)。在此基础上,通过对6根DSHCC增强RC梁和4根高性能复合砂浆增强RC梁受弯性能进行对比试验,分析DSHCC层对增强RC梁受弯破坏模式、承载力、变形能力以及裂缝分布等的影响,并通过编制程序分析DSHCC增强RC梁受弯破坏过程,推导相应的极限承载力简化计算式。结果表明:DSHCC的弹性模量、极限抗拉强度和抗压强度相较于普通SHCC均有大幅提高;DSHCC增强RC梁在极限承载力和耐久性方面优势明显,但未配筋的DSHCC增强梁变形能力仍存在不足(其延性系数仅为基梁的1/6),可通过在DSHCC增强层中配置少量钢筋来提高增强梁的延性,试验得到DSHCC增强层配筋率为0.6%和0.9%的增强RC梁延性系数分别提高了40%和100%;增强层配置少量钢筋后DSHCC增强RC梁不仅具有较高承载能力和耐久性能,还具有较好的延性能力。
In order to deal with the shortcomings of low modulus of elasticity and low strength of strain-hardening cementitious composites (SHCC), densification method was used to improve ordinary SHCC, and a compact strain hardening cement-based composite (DSHCC) suitable for RC beam reinforcement was developed. On this basis, by comparing the flexural behavior of RC beams reinforced with 6 DSHCC reinforced RC beams and 4 high performance composite mortars, the flexural failure modes, bearing capacity, deformation capacity and fracture distribution of RC beams strengthened by DSHCC were analyzed. And so on, and through the compilation of procedures to analyze DSHCC RC beams to enhance the process of bending failure, derived the corresponding simplified calculation of ultimate bearing capacity. The results show that: the elastic modulus, ultimate tensile strength and compressive strength of DSHCC are greatly increased compared with ordinary SHCC; DSHCC reinforced RC beams have obvious advantages in ultimate bearing capacity and durability, but the un-reinforced DSHCC reinforced beams Deformation capacity is still insufficient (the ductility coefficient is only 1/6 of the base beam). The ductility of the strengthened beam can be increased by configuring a small amount of steel reinforcement in the DSHCC reinforcement layer. The reinforcement ratio of DSHCC reinforced layer is 0.6% and 0.9% The ductility coefficient of reinforced RC beams is increased by 40% and 100% respectively. The DSHCC reinforced RC beams with a small amount of reinforcement reinforcement layer have not only high carrying capacity and durability, but also good ductility.