裂缝会对混凝土结构的承载能力和耐久性产生不利的影响,宽深裂缝的影响尤为严重.基于浙江省新岭隧道改扩建工程中旧有隧道张开裂缝的开展情况,设计了碳纤维布修加固大尺寸无缺陷素混凝土梁和碳纤维布修复带宽深预制裂缝大尺寸素混凝土梁的弯曲试验,试验表明碳纤维布对素混凝土梁的弯曲性能具有显著地修复加固效果.对于无损伤混凝土梁,底部粘贴碳纤维布加固可使其极限承载能力提高65%左右;而对于带有预制裂缝的混凝土梁,底部粘贴碳纤维布修复可使其承载能力提高250%左右.其最后的破坏模式为碳纤维布与混凝土梁底部剥离致使减弱甚至失去对混凝土中裂缝的约束而导致裂缝快速发展,最终发生失稳破坏.碳纤维布对于混凝土梁的修复加固效果取决于二者的黏接性能,无论混凝土梁是否带有损伤,底部粘贴碳纤维布进行修复加固后二者极限承载能力接近.因此,碳纤维布修复加固带损伤的混凝土结构具有明显的效果.%Cracks in concrete will weaken the load carrying capability and durability of concrete structures,especially for those wide and deep ones.Flexural tests on concrete beams repaired and strengthened by pasting a layer of carbon fiber sheet on their bottom were carried out based on the crack opening situation of Xinling highway tunnel in Zhejiang province.It shows that this method of strengthen and repair would improve the load carrying ability by 65% for the concrete beams without any damage and 250% for the ones with a pre-casted notch in their midspan,respectively.All reinforced beams failed due to the peeling off of carbon fiber sheets.And the ability of repair and strengthen relied on the bonding strength of carbon fiber sheets to concrete substrates,so the ultimate flexural strength of all reinforced beams are almost the same.However,the utility for carbon fiber sheets repairing notched beams is much better than strengthening ones without any damage.
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