【作者】 何波；

【导师】 李杉；

【作者基本信息】 武汉大学 ， 结构工程， 2023， 硕士

【摘要】 碳纤维编织网增强高延性地聚合混凝土(Carbon Fiber Reinforced Polymer Grid Reinforced Engineered Geopolymer Concrete,FGGC)是由碳纤维编织网(CFRP)和高延性地聚合物(EGC)结合而成的新型复合材料,充分结合CFRP抗拉强度大、EGC多缝开裂等优点,弥补传统FRP加固法中粘结剂耐久性差的缺陷,而且地聚合物取材于工业废弃物,符合绿色环保的理念。将FGGC作为混凝土加固材料,可以提高混凝土的极限承载力与延性。本文对FGGC加固混凝土短柱轴压力学性能开展研究,设计了FGGC加固混凝土短柱、预损伤混凝土短柱以及RC短柱的轴压试验,从试件破坏形态、峰值荷载与峰值应变、荷载-位移曲线、延性等分别研究CFRP网格层数、混凝土强度、预损伤水平等对试件轴压力学性能的影响。主要内容如下:(1)对36个FGGC加固素混凝土短柱进行轴压试验,影响参数考虑混凝土强度、CFRP网格层数,发现FGGC加固层加固效果良好,不仅改善了柱的破坏形态、提升延性,2层CFRP网格的FGGC加固柱相较于未加固柱提升幅度80%以上;EGC加固层对素混凝土短柱承载力提升幅度为66%,延性提升30.01%;混凝土强度增加虽然能提高试件的峰值荷载与峰值位移,但对试件延性的提升较小。(2)对12个FGGC加固预损伤混凝土短柱进行轴压试验,结果表明:FGGC加固层能改善预损伤混凝土短柱的破坏形态,减小初始损伤带来的轴压力学性能下降的影响,修复损伤混凝土的极限承载力与轴向、环向变形能力,但是嵌入CFRP网格层数过多也会削弱加固层对于试件延性的提升效果。(3)对10个FGGC加固RC短柱进行轴压试验,结果表明:随着CFRP网格层数的增加,加固柱峰值荷载和峰值位移逐渐增加,2层CFRP网格的FGGC加固柱相较于未加固柱提升幅度在50%以上;混凝土强度增加,试件延性有所提升,峰值荷载逐渐提高,而峰值位移有下降趋势。(4)对已有约束混凝土承载力计算模型进行整理,讨论了FGGC加固层的约束对核心混凝土承载能力的影响,对FGGC加固素混凝土短柱、损伤混凝土短柱以及RC短柱核心混凝土极限应力模型进行修正,获得承载力计算公式,计算结果与试验结果吻合度良好,计算模型能够较为精确的预测FGGC加固混凝土柱的极限承载力。更多还原

【Abstract】 Carbon Fiber Reinforced Polymer Grid Reinforced Engineered Geopolymer Concrete(FGGC)is a new type of fiber reinforced composite material.By carbon fiber woven mesh(CFRP)and high ductivity polymer(EGC)combination,can make full use of CFRP tensile strength,EGC multi-crack cracking and other advantages,make up for the traditional FRP reinforcement in the adhesive durability of poor defects,and geoppolymer based on industrial waste,in line with the concept of green environmental protection.Using FGGC as concrete reinforcement material can improve the ultimate bearing capacity and ductility of concrete.This paper studies the axial pressure performance of FGGC reinforced short concrete column,and designs three axial compression tests of FGGC reinforced short concrete column,pre-damaged short concrete column and RC short column.The effects of the number of CFRP grid layers,concrete strength and pre-damage level on the axial compressive properties of specimens were studied from the failure form,peak load and peak strain,load-displacement curve,ductility,etc.The main contents are as follows:(1)The axial compression test is carried out on 36 FGGC reinforced plain concrete short columns,which affects the parameters including concrete strength and the number of CFRP grid layers.It is found that the FGGC reinforced layer has a good reinforcement effect,which not only improves the failure form of the columns,improves the ductility,but also improves the ultimate bearing capacity of the specimens.Compared with the unreinforced columns,the FGGC reinforced columns with two layers of CFRP grid can be lifted by more than 80%.EGC reinforced layer increases the bearing capacity of plain concrete short columns by 66%and the ductility by30.01%.Although the increase of concrete strength can improve the peak load and peak displacement of the specimen,it has little effect on the ductility of the specimen.(2)Axial compression test was conducted on 12 FGGC reinforced pre-damaged concrete short columns,and the results showed that:The FGGC reinforced layer can improve the failure form of the pre-damaged concrete short columns,reduce the impact of the initial damage on the decline of axial compressive properties,and repair the ultimate bearing capacity and axial and circumferential deformation capacity of the damaged concrete.However,too many embedded CFRP grid layers will also weaken the enhancement effect of the reinforced layer on the ductility of specimens.(3)The axial compression tests were carried out on 10 FGGC reinforced RC short columns.The results show that the peak load and peak displacement of reinforced columns gradually increase with the increase of the number of CFRP grid layers.Compared with the unreinforced columns,the increase of FGGC reinforced columns with 2 layers of CFRP grid is more than 50%,but the ductility decreases slightly.With the increase of concrete strength,the ductility of the specimen increases,the peak load increases gradually,and the peak displacement has a downward trend.(4)The existing constrained concrete bearing capacity calculation models are sorted out,and the influence of the constraints of FGGC reinforcement layer on the bearing capacity of core concrete is discussed.The ultimate stress models of FGGC reinforced plain concrete short column,damaged concrete short column and RC short column core concrete are modified,and the bearing capacity calculation formula is obtained.The calculated results are in good agreement with the test results.The calculation model can accurately predict the ultimate bearing capacity of FGGC reinforced concrete column.更多还原