【作者】 沈承金；

【导师】 强颖怀；

【作者基本信息】 中国矿业大学 ， 矿物材料工程， 2009， 博士

【摘要】 在全面调研国内外大跨径铺装层体系的使用状况,分析钢桥面铺装层病害类型和主要原因。分析结果表明:推移、裂缝、车辙、粘结层的剪切破坏是沥青混凝土铺装层病害的主要表现形式,其主要原因为钢桥面板刚性不足、沥青混凝土材料强度低、车载过大、铺装工艺和铺装体系设计不合理等。本文首次提出铺装层下界面腐蚀问题,并研究界面腐蚀与铺装层弱化的相关性。实验研究不同渗透压和循环渗透周次下水的渗透规律。结果表明随着水渗透压增加、水渗透时间增加、水循环渗透周次增加,均促进铺装层表面或孔隙内水向粘结层与防腐蚀层间界面渗透。当渗透压大于0.3Mpa时,这种倾向明显。分别对无机富锌、环氧富锌和电弧喷锌涂层的腐蚀电位、腐蚀速率、极化特性、阻抗、腐蚀现象和产物研究。研究表明:在模拟的桥面雨水环境下,电弧喷锌涂层为均匀腐蚀,无机富锌涂层和环氧富锌涂层为点腐蚀。随着腐蚀时间的推移,电弧喷锌涂层腐蚀速率处于相对稳定,而无机富锌涂层和环氧富锌涂层开始腐蚀速度大,随后腐蚀相对稳定;锌的腐蚀产物主要为锌的氧化物、含CO32-、Cl-、SO42-、OH-等锌盐。通过对沥青粘结层--锌涂层结构在粘结层不同破损方式下的腐蚀行为研究,当粘结层遭到刻划破损或剥离破损时,锌涂层的腐蚀被加速,因此沥青粘结层下锌涂层的腐蚀表现为电荷传质电化学腐蚀和扩散腐蚀共同作用机制。通过对沥青铺装层+沥青粘结层下锌涂层的腐蚀研究,在无载荷状态下,沥青铺装层+沥青粘结层下锌涂层的腐蚀程度要比单一沥青粘结层下锌涂层腐蚀程度弱,体系下锌涂层腐蚀是锌的活化腐蚀——氧化及其产物堆积——再活化腐蚀的交替进行过程。剪切疲劳寿命研究结果表明:锌涂层腐蚀时两种铺装层体系的剪切疲劳寿命均明显下降,铺装层剪切位移明显加大;随着疲劳载荷的增加,这种变化更加明显。并且,喷锌涂层腐蚀时造成铺装层位移最大。采用ANSYS有限元计算软件,模拟计算富锌涂层界面腐蚀对动载荷下沥青混凝土铺装层应力和应变变化规律,研究界面腐蚀尺寸对沥青混凝土铺装层界面和表面应力和应变变化特征。结果表明,当铺装层下腐蚀尺寸小于500㎜×500㎜时,铺装层表面应力大于底部应力;当铺装层下腐蚀尺寸大于500㎜×500㎜时,铺装层底部应力大于表面应力,并且横向应力大于纵向应力,甚至出现铺装层底部和表面最大应力方向不一致,使铺装层处于底部纵向位移、表面横向位移的最不利状态。实验探索自放热型防腐涂层。结果表明:它与钢板结合力达30～40Mpa以上,与沥青粘结层结合力达到2～3Mpa,在5%NaCl+Na2CO3+Na2SO4中腐蚀电流在50μA以内,在5%NaCl中腐蚀电流在100μA以内,涂层无界面腐蚀。该论文有图85幅,表17个,参考文献100篇。更多还原

【Abstract】 A plenty of application of long-span steel bridge pavement system and its current condition were investigated in this dissertation. The disease type and possible reason of the paved layers were analysed as well. The results indicated that the diseases are mainly shearing, cracking, rutting and breakage of asphalt binding coating, and the reasons for diseases are briefly rigidity shortage of steel bridge deck, poor asphalt concrete materials, overloading, disqualified paved technology and unresonable pavement system. It is proposed firstly and researched in this dissertation that the interface corrosion of asphalt binding and zinc antisepsis coatings under the paved layer on the deck has relevant influence on decline of the layer.The water penetrative mechanism was derived from the study under the conditions of different pressure or pressure cycles. The results showed that the water on the surface or in asphalt layer penetrates to interface between the asphalt binding coating and zinc antiseptic coating. Furthermore, the quantity of penetrated water is increased with process pressure, time and pressure cycles, and this trend is in evidence when the pressure is beyond 0.3Mpa.The corrosive performance of zinc coatings was systematically investigated through corrosive electricty potential, corrosion rate, polarization property, electrochemical impedance spectroscopy analysis, corrosion appearance and corrosive products on inorganic rich zinc coating, epoxy rich zinc coating and arc spraying zinc coating. The uniform corrosion mechanism for arc spraying zinc coating and dot corrosion mechanism for inorganic and epoxy rich zinc coatings are summarized. The corrosion rate is comparatively steady with time increasing for arc spraying zinc coating, but the corrosion rate for the other two coatings--inorganic and epoxy zinc coatings is increased initialy and then kept unchanged subsequently with time increasing. Moreover, the zinc corrosive products are mainly zinc oxides and zinc salts including CO32-,Cl-, SO42-,OH- ion.The corrosive characteristics of the asphalt binding and zinc coating systems under different breaking modes for binding coating were discussed. Both asphalt binding and zinc coating systems represent composite corrosion mechanism which has synchronously charge transportation and ions diffusion.The corrosive degree of the zinc coating inside the system which is composed of the zinc coating and asphalt binding coating and asphalt pavement layer , is poorer than the other zinc coating inside the system which is composed of the zinc coating and asphalt binding coating. The zinc coating corrosion process involves activation-oxidation-reactivation.The shear fatigue experiment of the two systems were carried out whether or no corrosion. The results showed that the shear fatigue strength of two systems decreases obviously, and the shear displacement increases apparently when the zinc coating is in corrosion condition, these phenomenon are more remarkable with increasing fatigue load.In this research, The distribution pattern of stress and strain of the paved layer was derived from ANSYS analysis. The computation results indicated that surface stress is bigger than interface stress when the zinc coating corrosive area is smaller than 500mm×500mm. Moreover, when zinc coating corrosive area exceeds 500mm×500mm, the paved layer surface stress is smaller than interface stress, and stress in transversal is bigger than longitudinal. Indeed, the surface stress is not consistent with interface with regard to paved layer, such as the longitudinal displacement in interface is converse absolutely to the transversal displacement in surface.A new type antisepsis coating was exploited. The results showed that the bond strength of this new coating is more than 30-40Mpa to steel deck, and 2-3Mpa to asphalt binding coating. Moreove, this new coating possesses excellent corrosion resistance, the corrosive current is lower to 50μA in 5%NaCl+Na2CO3+Na2SO4 solution, and is not more than 100μA in 5%NaCl solutin, and no interface corrosion occures.更多还原