【作者】 徐李麟；

【导师】 崔圣爱；

【作者基本信息】 西南交通大学 ， 结构工程， 2024， 硕士

【摘要】 随着绿道桥梁的普及和服务需求的增加,绿道桥面铺装层面临使用寿命、资源和能源等方面的挑战。在荷载、环境等因素的耦合作用下,桥面铺装层极易发生早期病害,使用寿命缩短,这将严重影响结构安全。聚合物混凝土是一种适用于绿道桥面的铺装材料,目前聚合物混凝土桥面铺装层结构设计体系欠缺,存在铺装层抗裂性能较差、粘结损伤机理不明确、泛碱引起的外观颜色不适应等系列问题。鉴于此,本文依托成都市科技计划项目（2021-YF05-00138-SN）,以成都锦城绿道建设项目为案例,围绕实际工程中存在的问题和不足之处,开展绿道桥梁玄武岩纤维棒-聚合物混凝土性能研究。主要研究内容和结论如下:（1）通过正交试验研究了聚灰比、玄武岩纤维（BF）掺量、聚合物乳液类型以及矿物掺合料对力学性能的影响。丁苯乳液兼顾了混凝土的力学性能和一定的工作性,优选出的矿物掺合料掺量为5%硅灰+5%微珠。掺入玄武岩纤维棒（BFB）后的28d抗压和抗折强度相较BF提升了5.34%和9.86%,优选出的聚灰比为3%和6%。（2）以聚灰比、BFB掺量为变量,开展了BFB-PC的断裂性能研究。聚合物乳液和BFB的加入能提升试件破坏时的位移值和应变值,聚灰比为6%,BFB掺量为2%时混凝土的断裂能、起裂韧度和失稳韧度最大。裂缝扩展阻力随裂缝扩展长度的增大而增大,断裂过程区长度随有效裂纹长度的增大先线性增大后快速减小,所有工况的最大断裂过程区长度均为28mm左右。（3）研究了BFB的纤维增强指数（RI）对聚合物混凝土不同弯曲韧性评价指标的影响。RI的阈值为37.5和90,弯曲韧性评价指标随RI和聚灰比的增大而增大,且与RI呈二次函数关系,裂缝形貌的复杂程度提高,指标T_2（n-1）（n）随着裂缝分形维数的增大而增大。部分工况呈现挠曲软化行为,剩余承载力更高,与不掺聚合物相比,聚灰比为6%时的韧性指标更高,掺入聚合物改善了BFB与基体的界面性能。考虑纤维取向系数、长度有效系数的弯曲韧性计算模型可靠,弯曲韧性增量理论值与试验值的误差小于15%。（4）以聚灰比、BFB掺量为变量,研究了不同因素对铺装材料干缩性能和界面粘结强度的影响。掺入聚合物乳液和BFB使试件28d的干缩率先减小后增大,干缩率符合双曲线计算模型。单掺BFB、聚合物乳液和复掺均能提升界面劈拉强度,聚灰比为3%,BFB掺量为1%的界面劈拉强度最高,比基准组提升了39.47%,界面剪切强度与界面劈拉强度的规律几乎一致。建立了界面劈拉强度和界面剪切强度的模糊逻辑预测模型,平均误差分别为1.55%和8.26%。（5）研究了偏高岭土（MK）、硅氧烷憎水剂（SP）和硫铝酸盐水泥（SAC）对普通硅酸盐水泥（OPC）混凝土泛碱性能的影响,并应用于聚合物混凝土中进行验证。MK、SP和SAC均能改善OPC的泛碱,且抑制泛碱的机制不同,二次泛碱面积率的大小顺序为MK<SAC<SP<OPC,应用到聚合物混凝土中的规律相同。与OPC相比,MK、SP和SAC均对钙源含量有不同程度的较少,并优化了空隙空间结构,不同孔隙等效直径对渗透率的影响可以用孔隙的体积分布描述。空隙连接段的等效半径越大,迂曲度越小,孔隙的渗透能力越好,连接段的垂直迂曲度>水平迂曲度>总迂曲度。总路径数与孔隙数之比和孔隙率呈线性关系,交联孔数与孔隙数之比和孔隙率呈二次函数关系。更多还原

【Abstract】 With the popularization of greenway bridges and the increase of service demand,the pavement of greenway bridge deck faces challenges in terms of service life,resources and energy.Under the coupling effect of load,environment and other factors,the bridge deck pavement layer is prone to early diseases and the service life is shortened,which will seriously affect the structural safety.Polymer concrete is a kind of paving material suitable for greenway bridge deck.At present,the structural design system of polymer concrete bridge deck pavement layer is lacking,and there are a series of problems such as poor crack resistance of pavement layer,unclear bonding damage mechanism,and unsuitable appearance color caused by efflorescence.In view of this,based on the Chengdu Science and Technology Plan Project（2021-YF05-00138-SN）,this paper takes Chengdu Jincheng Greenway construction project as a case study,and studies the performance of basalt fiber bar-polymer concrete of greenway bridge around the problems and shortcomings in the actual project.The main research contents and conclusions are as follows:（1）The effects of polymer-cement ratio,basalt fiber（BF）content,polymer emulsion type and mineral admixture on mechanical properties were studied by orthogonal test.The styrene-butadiene emulsion takes into account the mechanical properties and certain workability of the concrete,and the optimal mineral admixture content is 5%silica fume+5%cenosphere.After adding basalt fiber bar（BFB）,the compressive strength and flexural strength of 28d are increased by 5.34%and 9.86%compared with BF,and the optimal polymer-cement ratio is 3%and 6%.（2）The fracture properties of BFB-PC were studied with polymer-cement ratio and BFB content as variables.The addition of polymer emulsion and BFB can improve the displacement value and strain value of the specimen when the specimen is destroyed.When the polymer-cement ratio is 6%and the BFB content is 2%,the fracture energy,initiation toughness and instability toughness of the concrete are the largest.The crack propagation resistance increases with the increase of the crack propagation length.The length of the fracture process zone increases linearly with the increase of the effective crack length and then decreases rapidly.The maximum fracture process zone length of all working conditions is about 28mm.（3）The effect of fiber reinforcement index（RI）of BFB on different flexural toughness evaluation indexes of polymer concrete was studied.The thresholds of RI are 37.5 and 90.The flexural toughness evaluation index increases with the increase of RI and polymer-cement ratio,and has a quadratic function relationship with RI,and the complexity of fracture morphology increases,the index T_2（n-1）（n）increases with the increase of fracture fractal dimension.Some working conditions show flexural softening behavior,and the residual bearing capacity is higher.Compared with the non-doped polymer,the toughness index is higher when the polymer-cement ratio is 6%,and the incorporation of polymer improves the interface performance between BFB and the matrix.The flexural toughness calculation model considering fiber orientation coefficient and length effective coefficient is reliable,and the error between the theoretical value of flexural toughness increment and the experimental value is less than 15%.（4）The effects of different factors on the drying shrinkage and interfacial bonding strength of pavement materials were studied by taking the polymer-cement ratio and BFB content as variables.The addition of polymer emulsion and BFB makes the dry shrinkage of the specimen decrease first and then increase at 28d,and the dry shrinkage rate conforms to the hyperbolic calculation model.Single doping BFB,polymer emulsion and compound doping can improve the interfacial splitting tensile strength.The interfacial splitting tensile strength is the highest when the polymer-cement ratio is 3%and the BFB content is 1%,which is 39.47%higher than that of the reference group.The interfacial shear strength is almost the same as the interfacial splitting tensile strength.The fuzzy logic prediction models of interfacial splitting tensile strength and interfacial shear strength were established,and the average errors were 1.55%and8.26%,respectively.（5）The effects of metakaolin（MK）,siloxane powder（SP）and sulphoaluminate cement（SAC）on the efflorescence properties of ordinary portland cement（OPC）concrete were studied and applied to polymer concrete for verification.MK,SP and SAC can improve the efflorescence of OPC,and the mechanism of inhibiting efflorescence is different.The order of secondary efflorescence area rate is MK<SAC<SP<OPC,and the same law is applied to polymer concrete.Compared with OPC,MK,SP and SAC had less calcium source content and optimized the pore space structure,the effect of different pore equivalent diameters on permeability can be described by the pore volume distribution.The larger the equivalent radius of the void connection section is,the smaller the tortuosity is,and the better the permeability of the pore is.The vertical tortuosity of the connection section>the horizontal tortuosity>the total tortuosity.The ratio of the total number of paths to the number of pores and the porosity are linear,and the ratio of the number of cross-linked pores to the number of pores and the porosity are quadratic.更多还原