【作者】 陈凤山；

【导师】 赵国藩；

【作者基本信息】 大连理工大学 ， 结构工程， 2007， 博士

【摘要】 多年来的码头调查证实，海洋环境下的钢筋混凝土结构锈蚀严重，造成保护层混凝土开裂，甚至剥落，使钢筋向外界环境严重裸露，导致结构耐久性严重不足。近些年来，国内外兴起了对碳纤维复合材料应用于结构加固的研究，特别是这种材料有着非常好的抗拉性能和耐久性能。因此，本文结合原中港集团2003年度重点技术开发项目《海工混凝土结构碳纤维加固成套技术研究》，主要开展了以下的研究工作：1、研制了适合在潮湿混凝土表面粘贴CFRP进行加固用的系列湿固化粘结剂。试验证明，其本体强度、工艺性能、正拉粘结性能均能满足我国加固规程中的性能要求。为了研究这种材料在加固中的广泛适用性，还进行了用以浸渍和粘贴CFRP时的正拉性能试验，并同市场上常见的Araodite牌配套粘结树脂进行了试验对比。此外，还通过钢筋混凝土梁的弯曲试验，证明了这种湿固化粘结剂完全能满足CFRP对结构的加固需要，并且性能不低于使用Araodite时的性能。2、进行了CFRP短期力学性能试验，同时还进行了CFRP浸渍于碱溶液、浸渍于盐溶液、经人工老化后的力学性能试验。试验证实，上述几种长期环境条件作用对CFRP的极限强度影响不大，但能显著降低CFRP的极限延伸率，碱溶液浸渍、盐溶液浸渍显著降低了CFRP的弹性模量，而人工老化则几乎没什么影响。试验结果分析证明，应用于加固结构分析的CFRP的应力-应变关系，可应用线弹性关系。3、通过试验研究，证实了在混凝土表面粘贴CFRP，能有效地阻隔Cl~-向混凝土渗透。因此，当海工混凝土结构使用外贴CFRP方法进行维修加固时，可以考虑将CFRP作为表面防护的一部分。4、通过24片试验梁的加载试验，研究了钢筋混凝土梁CFRP抗弯加固的相关问题。试验证明，粘贴CFRP对钢筋混凝土梁能有效地提高抗弯承载力和刚度，并能有效地延缓裂缝的开展。CFRP用量越大，这种作用效果就越好。此外，随着钢筋配筋率的提高，CFRP加固的效果变得越来越不明显，CFRP的作用在构件的带裂缝工作阶段比整体工作阶段时要突出。在有限的CFRP用量下，粘贴CFRP一般不改变构件的破坏模式。分析结果证实，用我国加固规程中的抗弯承载力公式计算，计算值与试验值比较吻合，可以应用于海工混凝土梁CFRP加固时梁的承载力计算。5、通过4片钢筋混凝土单向板的加载试验，研究了在受拉区粘贴CFRP对构件提高抗弯承载力、延缓裂缝开展、提高结构刚度的有效性。试验证实，CFRP加固钢筋混凝土板的破坏模式均为弯曲破坏。分析结果证明，抗弯承载力试验值低于按照我国CFRP加固规程的计算值。因此，宜采用一定的折减系数计算为宜。6、通过28片试验梁的抗剪加载试验，在试验梁分别经过了腐蚀、加载预裂、腐蚀后加载预裂等后，粘贴CFRP进行抗剪加固，研究了各种情况下CFRP加固梁的力学性能。试验发现，腐蚀损伤、加载预裂损伤对CFRP加固试验梁的性能影响不大，并且有腐蚀和加载预裂CFRP加固试验梁的荷载-挠度曲线为双直线折线状。除了闭口形式的横向CFRP条加固对试验梁抗剪强度提高比较突出、表现出较好的延性外，U形和侧面粘贴之间的加固效果相差很小，破坏模式均为脆性破坏。分析结果证明，抗剪承载力试验值均低于按照我国CFRP加固规程的计算值。因此，宜在计算公式中引入折减系数。7、进行了18根素混凝土方形截面柱、12根素混凝土圆形截面柱、12根钢筋混凝土方形截面柱的加载试验，分别研究了外包CFRP对上述三种梁加固后的性能。试验说明，外包CFRP可以大幅度提高素混凝土柱的轴心抗压承载力，但在不同程度上降低了延性。尤其对于圆形截面柱，提高幅度会随着外包面积比例的增加而提高很显著，全包时甚至达到36％。而CFRP加固钢筋混凝土柱也能提高其轴向抗压承载力，但提高幅度远不如对素混凝土柱的提高幅度。更多还原

【Abstract】 It have been confirmed by site investigations for many years past that crack or evendelamination of cover due to rebars corrosion in reinforced concrete structures is a mainreason resulting in rebars exposing completely to external environment, and reduce thestructures durability to an unacceptable level. And carbon fiber reinforcement polymer(CFRP) is largely applied for structures rehabilitating around world including China becauseof extraordinary properties, especially its tension and durability properties. Hence, thefollowing research works are developed based on the project Research on technology systemof coastal concrete structures strengthened with CFRP which launched and supported byCHEC:1. Moisture-curable adhesives applicable for bonding CFRP on moisture concrete surfaceare developed, and materials strength, bond strength or technical properties meet all therequirements given by the nation’s specification. In order to confirm extensive applicability ofthe adhesives, further testing researches are performed on bond strength when the adhesivesapplied to saturate carbon fiber and then bond on moisture concrete surface, and comparing tothat when Araodite adhesives, a kind of marketable, are applied. Furthermore, applicabilityof the moisture adhesives have also been confirmed through bending test of reinforcedconcrete beams strengthened with CFRP, and it can be observed that the performance of thebeams bonded by the moisture adhesives seems not worse than those bonded by Araoditeadhesives.2. Short-term and long-term mechanical properties of CFRP are researched throughlaboratory test and the specimens for long-term have been experienced immersing in alkalisolution, salt solution or laboratory fast aging respectively before tension test. The aboveenvironment factors have almost no effect on ultimate strength of CFRP, however, can reduceultimate elongation obviously,while can increase modulus. The relationship betweenσandεof CFRP is elastic and linear as per test results, and the conclusion can be applied in analyzingCFRP strengthened structures.3. It is observed that Cl~- can be prevented effectively from immigrating into concrete whenconcrete surface bonded with CFRP through laboratory test. Therefore, besides asreinforcement when coastal concrete structures are repaired and strengthened, CFRP bondedon surface of concrete can be regarded as a part of corrosion protection system on concretesurface. 4. There are 24 beams experienced loading test for bending performance of reinforcedconcrete beams strengthened with CFRP. The results indicate that bending capacity andstiffness of reinforced concrete beams may increase, and crack may be controlled afterreinforcing by bonding CFRP externally. Much CFRP is applied, the above effects seemsmuch obviously. CFRP play a higher role on increasing beams performance after crack thanbefore, and the function gradually reduce as content of rebars increased. Normally, the failuremode of reinforced concrete won’t change after being reinforced with CFRP forbending. Analysis on testing data indicate that there are an acceptable difference betweentesting value and calculation value which based on formula in the nation’s specification, andthe formula can be introduced into CFRP strengthening coastal concrete structures.5. There are 4 reinforced concrete plates experienced loading test for bending performanceof reinforced concrete plates strengthened with CFRP. Similarly to reinforced concrete beamsstrengthened with CFRP, bending capacity and stiffness of reinforced concrete plates mayalso increase, and crack may be controlled after reinforcing by bonding CFRP externally. Thefailure mode are caused by bending. In addition, analysis on testing data indicate that testingvalues is lower than calculation values which based on formula in the nation’sspecification. Thus, a reduction factor will be introduced into calculation system for CFRPstrengthening coastal concrete structures.6. There are 28 beams experienced loading test for shear performance of reinforced concretebeams strengthened with CFRP. Besides reference beams, there are still some beamsexperienced fast corrosion or pe-load to crack before bonding CRRP. The results indicatethat there is almost no effect of damage due to corrosion or pre-load on performance ofreinforced concrete beams strengthened with CFRP. In addition, the load-deflection curve isformed by two beelines for those experienced corrosion or pe-load. Shear capacity can beobviously increased and keep well ductility when completely wrapped CFRP scheme isapplied for shear strengthening, while there is very small different performance between3-sided "U-wrap" and 2-sided wrap, and the failure is brittle. Analysis on testing dataindicate that testing values is lower than calculation values which based on formula in thenation’s specification. Thus, a reduction factor will be introduced into calculation system forCFRP strengthening coastal concrete structures.7. There are 18 square-section plain concrete columns, 12 circle-section plain concretecolumns, 12 square-section reinforced concrete columns respectively experienced loading testfor axial compression performance of column wrapped with CFRP. The test results indicate that axial compression capacity of plain concrete columns increase largely when wrappedwith CFRP. Much more area wrapped with CFRP, much higher capacity of plain concretecolumns are. The maximum increment of axial compression capacity is 36% whensquare-section plain concrete columns are completely wrapped with CFRP. Althoughwrapping CFRP can also increase axial compression capacity of square-section reinforcedconcrete columns, the increment seems much smaller than that of plain concrete columns.更多还原