喷射超高韧性水泥基复合材料加固带裂缝素混凝土梁的力学性能试验研究

Experimental study on mechanical performance of cracked plain concrete beams retrofitted by sprayed ultra high toughness cementitious composites

对既有受损混凝土结构的加固维修是地震灾后重建的重点之一。应用喷射超高韧性水泥基复合材料(UHTCC)的拉伸应变硬化特性,研究了带裂缝混凝土梁底部喷射20mm薄层UHTCC的加固作用。结果表明:薄层喷射UHTCC对混凝土梁的弯曲强度和弯曲刚度有明显的加固作用,可将带预制裂缝的混凝土梁极限承载力提高117.5%,使受损混凝土梁的承载能力恢复到相同尺寸无损混凝土梁承载能力相当的水平;此外混凝土梁底部薄层喷射UHTCC能将裂缝宽度控制在0.1mm以下的微裂缝,有利于提高混凝土梁的耐久性。

Reinforcing current damaged concrete structure is one of the points of the post-earthquake reconstruction. In this paper, the cracked concrete beams strengthened by 20 mm thin layer UHTCC are studied applying the ten- sile strain hardening properties of sprayed UHTCC. Test results show a dramatically improvement of 117.5% in the flexural strength when compared with the same concrete beams without being repaired by thin layer of sprayed UHTCC. Besides, cracks＇ widths were well controlled below 100urn in the layer of UHTCC and the width of crack in concrete is also well limited when the load was at a high level, which is good for the durability of concrete beams.