中文摘要：

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。

英文摘要：

Due to the issues of strain hardening cementitious composites（SHCC）with low Young＇s modulus and tensile strength,densified strain hardening cementitious composites（DSHCC）were developed using the densification method in SHCC,which were applicable to strengthen RC beams.Thereafter,the bending performances of 6 RC beams with flexural strengthening using DSHCC and 4RC beams with flexural strengthening using high performance mortar（HPM）were compared and tested.The influences of DSHCC on failure mode,bearing capacity,deformation,and crack distribution of strengthened RC beams were investigated.The failure process of RC beam with flexural strengthening using DSHCC was analyzed by the coded program,in which the corresponding simplified formula of ultimate bearing capacity was derived.The results show that elastic modulus,ultimate tensile strength and tensile strength of DSHCC greatly increase than those of normal SHCC.DSHCC has obvious advantages of increasing the ultimate bearing capacity and durability for strengthening RC beam,whereas the deformationcapacity of strengthened RC beam without reinforcement is still insufficient（the ductility coefficient of which is only 1/6that of RC beam）.It has been found that a small amount of steel reinforcement to DSHCC strengthening layer can increase the deformation capacity of strengthened RC beam.In the tests,0.6% and 0.9% reinforcement ratios for strengthening layer can make the ductility coefficient of strengthened RC beams increase 40% and 100%respectively.After adding a small amount of steel reinforcement to DSHCC layer,RC beam strengthened with DSHCC has not only high bearing capacity and durability,but also better deformation capacity.