CFRP加固受损再生混凝土板的抗弯性能试验研究

Experimental study on flexural performance of damaged recycled aggregate concrete slabs strengthened with CFRP

为了探究CFRP加固受损再生混凝土板的抗弯性能,制作了4块再生混凝土板(再生粗骨料取代率为50%),考虑预损伤等级及加载循环次数对试件加固性能的影响。通过试验与数值模拟研究,分析了试件的破坏模式、荷载-位移曲线及承载能力,并对规范中的承载力计算公式进行了修正。结果表明:CFRP加固再生混凝土板的破坏模式为CFRP脱落;当预损伤等级<0.4P_(m)(极限承载力)时,加固后的试件承载力变化不大;当预损伤等级≥0.4P_(m)时,加固后的试件承载力随预损伤等级的提升而降低;当预损伤等级<0.9P_(m)时,加载循环次数对试件的承载力影响很小;当预损伤等级≥0.9P_(m)时,试件承载力随加载循环次数的增大而显著降低;试件承载力随着CFRP加固层数的增加而增大;修正后的承载力计算公式具有较高的计算精度。

To investigate the flexural behavior of recycled aggregate concrete(RAC)slabs strengthened with carbon fiber-reinforced polymer(CFRP),four RAC slabs with a recycled coarse aggregate replacement rate of 50%were fabricated and tested.Considering the influence of pre-damage level and loading cycle on the strengthening performance of specimens,the failure mode,load-displacement curve,and bearing capacity of specimens were analyzed through experimental and numerical studies.The results show that the failure mode of CFRP-strengthened RAC slabs is CFRP-debonding failure.When the pre-damage level is less than 0.4P_(m),the bearing capacity of the specimens after strengthening does not change significantly.When the pre-damage level is greater than or equal to 0.4P_(m),the bearing capacity of the specimens after strengthening decreases with the increase of the pre-damage level.When the pre-damage level is less than 0.9P_(m),the loading cycle has little effect on the bearing capacity.When the pre-damage level is greater than or equal to 0.9P_(m),the bearing capacity of the specimens significantly decreases with the increase of the loading cycle.The bearing capacity of the specimens increases with the increase of the number of CFRP layers.The calculation formula of the bearing capacity is modified,and the modified formula has high calculation accuracy.