【作者】 耿飞；

【导师】 高培伟；

【作者基本信息】 南京航空航天大学 ， 道路与铁道工程， 2013， 博士

【摘要】 水泥混凝土道面裂缝的形成和发展演化非常复杂，其对结构的使用性、安全性和耐久性影响重大，实现裂缝控制和修复更是一个系统性的工程难题。基于水泥混凝土材料水化、凝结和硬化过程中的固有特性，采用全周期膨胀补偿收缩理论，以废弃的工业尾矿为原料，制备具有早、中期和后期稳定膨胀的高性能复合膨胀材料，系统研究组成、结构和性能间的相互关系，揭示其水化动力学特征和膨胀机理，提高水泥混凝土道面的主动抗裂能力；同时，针对水泥混凝土道面服役过程中的微细裂缝，为实现快速可靠的修复以阻碍有害介质的侵入，研制了丙烯酸类和环氧树脂共聚的高性能修补材料，阐明其性能特征和修复机理，提高水泥混凝土道面的防裂能力。论文研究有利于控制裂缝的产生和发展，抑制和降低道面结构性能的劣化，对提高水泥混凝土道面结构的耐久性和服役寿命具有重要的理论和工程应用价值。（1）鉴于传统膨胀剂的性能缺点，通过对白云石和菱镁石工业尾矿的优化配伍及煅烧制度设计，研究了不同组份、煅烧温度和保温时间等因素对高性能复合膨胀材料结构与性能的影响特征，确定了适宜的制备技术，研制了不同组份和性能的膨胀材料；分析了掺不同类型和用量膨胀材料水泥浆体凝结时间、标准稠度需水量和强度的变化规律，结果表明标准稠度用水量和凝结时间稍有增加，水泥浆体抗折强度提高6%~15%，而抗压强度略有增长；研究了水泥砂浆在不同龄期的自由变形、干缩变形和限制变形的变化特征，结果表明复合膨胀材料具有早、中和后期补偿收缩功能、且膨胀速率和总量可控，较高养护温度与湿度以及适宜煅烧制度有利于膨胀效应的发挥，在高温环境中的限制收缩可达到常温中的数倍。（2）研究了压蒸制度对膨胀混凝土膨胀率的影响特征，分析了压蒸前后混凝土抗压和抗折强度的变化规律；研究了膨胀材料种类、用量和养护温度等对混凝土自由变形、限制变形及自生变形在不同龄期的发展速率，用数值方法拟合了膨胀率的时变函数；计算了高性能复合膨胀材料的膨胀指数，分析了其随膨胀材料掺量和养护温度的变化特征；对膨胀混凝土在不同限制膨胀率和约束状态下内部应力场的分布特征进行了仿真分析，为其科学应用提供了依据。（3）分析了补偿收缩混凝土的基本理论以及膨胀和收缩两个阶段的形变关系，研究了复合膨胀材料品种以及不同水化时期的形貌、晶粒生长以及孔结构特征；试验研究了膨胀材料煅烧温度、保温时间和颗粒细度对水化活性的影响，分析了水化温度和溶液pH值对膨胀材料中MgO水化程度的影响特征，基于水化动力学方程计算了膨胀材料的水化反应速率常数和表观活化能；通过对膨胀材料水化动力学演变过程的分析，建立了膨胀材料中MgO水化成Mg(OH)2以及CaO水化成Ca(OH)2膨胀模型。（4）以水泥混凝土道面的微细裂缝为重点修复对象，以修补材料的初始粘度为控制点，优选甲基丙烯酸甲酯和环氧树脂为主要反应单体，进行了本体聚合的合成制度设计及试验研究，确定了高性能修补材料的合理制备技术；采用正交试验分析了修补材料组分和反应时间对初始粘度的影响规律，分析确立了初始粘度的时变特征及其与修补材料可灌性和收缩率的量化关系；研究了反应组分对高性能修补材料粘结强度、拉伸强度和断裂伸长率的影响规律，确定了高性能修补材料基体（RM）的最佳配比；采用有机硅与无机矿粉的复合进行改性，研究了高性能修补材料的力学、变形和热稳定性能，制备了有机优化（OMM）和复合优化（CMM）的高性能修补材料，综合性能显著提高，超过国家相关标准的要求。（5）试验研究了RM、OMM和CMM型高性能修补材料对水泥砂浆粘结能效的时变规律，分析了在盐溶液和快速冻融作用下粘结性能的变化，结果表明修复后砂浆的抗折断裂面未发生在修补处，7h粘结强度与砂浆基体相当；通过在混凝土试件中预制裂缝，对比研究了几种修复材料对混凝土修复能效，分析了断面破坏形式和界面粘结特征；利用有限元方法计算了混凝土裂缝不同修补状态下应力强度因子的变化规律，采用SEM和FT-IR测试分析了高性能修补材料断裂面的微细观形貌和结构中的特征官能团；基于高分子化学理论，阐释了环氧树脂与甲基丙烯酸甲酯、以及有机硅改性剂和无机矿粉改性的聚合反应原理，揭示了高性能修补材料力学和变形性能与其微观结构的关联性，并从物理作用力和化学键力研究了高性能修补材料对水泥混凝土裂缝的粘结修复机理。更多还原

【Abstract】 Due to the complexity of the generation mechanism and the developing evolution of cracks inconcrete pavement and their significant influence on the availability, safety and durability of thepavement, crack control and repair in concrete pavement are systematic engineering challenges.Based on the inherent characteristics of hydration, setting and hardening in concrete and the theory ofcompensating shrinkage with expansion in different periods, environment-friendly high-performancecomposite expansive materials with stable expansion in early, mid and late age were prepared withwasted industrial tailings as raw materials. The relationships of the constitute, the structure and theperformance of the materials were studied to reveal its hydration kinetic characteristics and expansionmechanism and also to enhance the cracking resistance of concrete pavement. For fine cracks in theconcrete pavement in service, an acrylic and epoxy resin copolymerized high-performance repairmaterial was used to hinder the invasion of the harmful mass. The performance characteristics andrepair mechanism of the materials were clarified. Therefore, the defense capability of concretepavement can be improved. The investigation in the dissertation is conducive to control the generationand the development of cracks, and to weaken the deterioration of the structural performance aftercracking. Consequently, the durability and service life of concrete pavement structures can beenhanced, which is of significance in theory and engineering practice.（1）Considering the disadvantages of traditional expansive agents, through the design ofcompatibility and calcining procedure for industrial tailings of dolomite and magnetite, the influencecharacteristics of the components, calcination temperature, soaking time and other relative factors onthe structures and the properties of high-performance composite expansion materials were discussedto determine a suitable preparation process and also different expansive components. Experimentalstudy on the basic properties of paste with high-performance composite expansion materials wasadopted. The effects of types and amounts of expansive components on the setting time, waterrequirement of normal consistency and strength were analyzed. It is shown that as the waterrequirement of normal consistency and setting time increased slightly, and there was a6%to15%improvement in the flexural strength of paste as well as the compressive strength. The influences ofthe type and dosage of expansive components, and curing temperature on the deformation properties of the paste and mortar were explored experimentally. The characteristics of the free，shrinkage andrestrained deformation of the mortar during different hydration periods were tested. It is found that thecomposite expansion component exhibited its compensation for shrinkage at early, mid and late age.Meanwhile the expansion rate and the total expansion amount can be controlled. It is discovered thathigher curing temperature and humidity as well as a suitable calcining procedure were conductive tothe expansion and the restrained shrinkage at high temperature could be multiple times of that onecuring in room temperature.（2）The stability and deformation development of the concrete with the expansion materials wasinvestigated based on the experiments. The effects of the autoclave procedure on the concreteexpansion rate were studied and the variation law for the flexural strength and the compressivestrength of the concrete before and after the autoclave were summarized. The effects of the type anddosage of expansive components, and the curing temperature on the growth rate of the free, restrainedand autogenous deformation of the concrete for different hydration periods were discussed. Thenumerical method was adopted to fit the expansive rate with time. The expansive index of thehigh-performance composite expansive component was calculated as well as its variation feature withthe dosage and the curing temperature of the expansive component was studied. Simulation wasapplied to the distribution feature of internal stress field of the expansion concrete under differentexpansion rates and different restrained conditions, through which the reasonable basis for theapplication of the composite expansive component can be expected.（3）The basic theory of concrete shrinkage compensation and the relation of deformations in thetwo stages-expansion or shrinkage were discussed. The microstructure, grain growth and porestructure characteristics for different composite expansion component types as well as differenthydration time were studied. Experimental results demonstrated the effect of the calcinationtemperature, heat preservation time and particle fineness of the expansive component on the hydrationactivity. The hydration degree of MgO in the expansion materials at different hydration temperaturesand pHs were also tested. With the aid of the hydration kinetic equation, the hydration reaction rateconstant and the apparent activation energy of the expansive component were computed. Through theanalysis of the evolution of hydration dynamics of the expansion materials, a physical expansionmodel for MgO hydrated into Mg(OH)2as well as CaO hydrated into Ca(OH)2was established.（4）The fine cracks in the concrete pavement were treated as the critical repair object and theinitial viscosity of the repairing material was set as a control start. Methyl methacrylate and epoxy resin were adopted as the main reactive monomers for the bulk polymerization according to synthesisdesign to determine the rational preparation methods. The orthogonal test was employed to analyzethe effects of the repairing component and the reaction time on the initial viscosity. The time-varyingcharacteristics of the initial viscosity were tested and the quantitative relation of the characteristicswith the groutability and the shrinkage of the repairing material were set up. Based on the orthogonaltest, the effects of the reactive monomer, the initiator, the plasticizer, and the curing agent on the bondstrength, the tensile strength and the elongation at break of high-performance repairing material wereinvestigated. It presented the best proportion of the high-performance repairing matrix. After modifiedwith silicone or inorganic mineral powders, the performances regarding to mechanics, deformationand thermal stability of the repairing material were studied. Due to organic optimization (OMM) andcomposite optimization (CMM), the high-performance repairing material, of which the overallperformance was improved remarkably even exceeding the requirements in the relevant nationalstandard, was prepared.（5）The time-vary law of the mortar bonding efficiency with the different types of highperformance repair materials distinguished by RM, OMM and CMM was discussed experimentally.The changes of the bonding properties of the repair materials in the salt solution and in rapidfreeze-thaw cycles were analyzed. It can be found that the mortar after repair did not break again atthe repair area, and the repaired part regained the bond strength as much as the mortar itself in7hoursafter repair. A comparative study of several repair materials was adopted to evaluate their repairefficiency to the compressive strength and the flexural strength of the concrete with prefabricatedcracks before and after repair. The experiments were also carried out to analyze the sectional failuremodes and interfacial adhesion characteristics. The change of stress intensity factor of concrete crackrepaired under different states was calculated by using finite element method. With the help of SEMand FT-IR tests, the microstructure of the fracture surfaces and the characteristic functional groups inthe structures of the concrete repaired with the high-performance repair materials were investigated.Based on the theory of polymer chemistry, the principles of epoxy resin polymerized with methylmethacrylate and silicone modifier polymerized with modified inorganic mineral powder wereexplained. For high-performance repair material, the correlation of the deformation and themechanical performance with the microstructures was revealed. The bonding repairing mechanism ofthe high-performance repair materials to the cracks in concrete was interpreted in two views of thephysical force and the chemical bonding force.更多还原