【作者】 尹健；

【导师】 周士琼；

【作者基本信息】 中南大学 ， 道路与铁道工程， 2003， 博士

【摘要】 本文以超细粉煤灰为基材，研制并开发出粉煤灰复合超细粉快速修补专用掺合料(CUFA Ⅱ)系列产品，等量取代水泥≥30％，配制的高性能快速修补砼(HPRRC)在12～48h内达到开放交通的要求，解决了破损的水泥砼路面整板翻修后快速开放交通这一问题，并大大降低工程成本。该产品是一种新型的环保绿色建材，应用前景十分广阔。本文主要研究成果如下：1、在系统研究了超细粉煤灰的物理性能、形貌、粉体效应微观机理的基础上，采用粉体优化组合、活化激发技术，复配的CUFA Ⅱ产品与32.5R及以上的普通硅酸盐水泥配制的HPRRC可达到12～48h开放交通所需的最低强度指标要求；该产品己工业化生产并推广应用。以粉煤灰为基材的CUFA Ⅱ用于水泥混凝土路面整板快速修补工程中，国内外未见报道。2、在大量试验研究的基础上，考虑到耐久性对化学成分的要求，参照即将出台的《高强高性能砼用矿物外加剂》(报批稿)和国外相关标准参加编制了本产品国内第一个超细粉煤灰矿物外加剂的企业标准Q／DBAA001—2002。3、采用有限元方法，建立数值模型，模拟在标准轴载条件下新老砼的受力状态，得出了修补区砼开放交通新老砼界面的临界粘结强度。根据我国标准的规定，参考国外的研究成果，提出了修补区砼开放交通的控制参数。4、采用多元回归分析方法探讨了影响12h、24h、28d高性能快速修补砼抗折强度的因素；还对影响HPRRC干缩性能、耐久性能的因素进行了分析，确定了HPRRC配合比设计参数。配制出和易性优良(坍落度30mm)12～48h能满足开放交通的HPRRC。5、HPRRC力学性能、耐久性能试验结果表明：无论早期还是后期，其折压比均比普通砼的有所提高，脆性有所降低；新老砼粘结性能优良；并具有优异的抗冻性、抗渗性、耐磨性，抗氯离子渗透能力强；体积稳定性大为提高，抗裂性好。6、通过优化HPRRC的配比，用与老混凝土强度接近的新混凝土对老混凝土进行修补后，在普通试验机和MTS试验机上对新老混凝土的本构关系进行了试验研究，结果表明：在等应力条件下老砼、HPRRC博士学位论文.中文摘要的应变与新一老硷的相比，应变的比率在普通试验机上为82.4一105%，在川、S上为90一121.3%，即三者变形是基本接近的。新一老硅及HPRRC应力一应变全曲线建议采用两段式拟合:上升段采用三次抛物线方程模拟，下降段采用有理分式模拟，理论值与试验结果吻合较好。该研究成果为新老混凝土结合面抗裂能力的提高提供了前期的理论基础。 7、自行研制的混凝土表面粗糙度测定仪，仪器设备简单，测试精度高，数据采集自动化，为评价混凝上断裂面的粗糙度提供了一种快速有效的测试仪器。线分数维D、灌砂平均深度h与新老硷界面粘结强度的试验结果表明:用线分数维来表征老硅表面的粗糙度，预测新老混凝土粘结强度结果的精度更高。 8、硬化浆体的化学结合水量、XRD、SEM试验结果表明:在12一24h内，矿物外加剂C、激发剂D的加入，可以促进掺粉煤灰的水泥浆体早期的水化速度，密实了水泥基材，改善了水泥石的孔结构;粉煤灰水泥石的cH峰值明显降低，AFt的谱峰大幅度增加;粉煤灰活性成分的二次水化反应，消耗了cH晶体，晶粒得到细化，并可明显地看出粉煤灰颗粒表面被水化硅酸钙凝胶所覆盖，生成了大量的钙矾石柱状晶体，到3d龄期可明显看出粉煤灰表面受到了严重的侵蚀。cUFAn粉体减水增强效应、火山灰效应和微集料密实填充效应，大大提高了硬化水泥石的早期强度。 9、HPRRC现已推广应用9.34万矿，使用至今未发现有开裂现象，耐久性优良，用户反映良好。为用户节约资金8377万元，厂家产生直接经济效益647万元，社会效益、环保效益非常显著。更多还原

【Abstract】 In this paper, a series of ultra-fine fly ash composite powder (CUFA II)products for rapid repair are researched and developed successly with the ultra-fine fly ash as matrix . CUFA II can replace cement equivalently more than 30%. High performance rapid repair concrete(HPRRC) in which CUFA II replaces cement equivalently more than 30% can meet the requirements of opening traffic within 12~48h,which solves the problem of opening traffic as soon as possible after damaged Portland cement concrete pavement are repaired for a whole plate, and the engineering cost is lowered greatly. CUFA II is a kind of new environmental friendly green building material.The main achievements in this paper are as following:1 Based on the systematical study about physical properties, particle morphologies and micro-mechanism of ultra-fine fly ash, CUFA II products are successly developed by means of optimizing the particle gradation and activation technique. HPRRC composed of CUFA II products and with the strength grade no less than 32.5R ordinary Portland cement can meet the minimum strength index demands. At present , CUFA II has been produced commercially and applied to engineering . The fact that CUFA II based on fly ash is applied to whole plate Portland cement concrete pavement rapid repair engineering has not been reported at home and abroad.2 By extensive experiments and research, in consideration of the requirements of durability to chemical composition, referring to "high strength high performance concrete mineral admixture " (draft report) and correlating standards in abroad, the first Technical Specification (Q/DBAA001-2002) of ultra-fine fly ash mineral admixture in china has been put forward.3 By finite element method, the stress of New-Old concrete is simulated in condition of standard axis loading .The critical bond strength of new-old concrete interface is obtained. According to Chinese standard and referring to foreign research results, the key parameters forrepaired concrete to open traffic are put forward.4 By means of multiple regression analytical method, the significant correlation factors with the flexural strength at the age of 12hours, 24hours and 28days are analysed. At the same time, the factors affecting dry shrinkage and durability are also analysed .The mix proportion parameters of HPRRC are determined, while HPRRC is good in workability (slump 30mm), and can meet the needs of opening traffic within 12~48h.5 . The experiment test results of mechanical properties and durability of HPRRC show: no matter at early age or later age, the ration of flexural strength to the cubic compression strength of HPRRC is higher than ordinary concrete, and the brittleness of HPRRC is reduced ;the bond performance of new-old concrete interface and chloride permeability are good; its resistance to freeze and thaw, permeability are all excellent; its volume stability is improved ,and its cracking resistance is good.6 With the optimization of the mix proportion of HPRRC and with the old concrete was repaired with HPRRC whose strength is close with that of the old concrete, the stress-strain curves of new-old concrete is tested on ordinary testing machine and MTS .The results show that under equal stress conditions, the ratios of the strain of old concrete ,HPRRC to new -old concrete are 82.4-105% on ordinary testing machine and 90-121.3% on MTS respectively. These demonstrate that the deformation of three kinds of concrete is basically similar. The stress-strain curve of new-old concrete and HPRRC, are suggested to be modeled by two sections: the ascending section of the stress-strain curve is simulated by cubic parabola equation and the descending section is simulated by rational fraction, where the theoretical value is in good agreement with the test value .The research results also provide a theoretical basis of earlier stage for improving crack resistance of new-old concrete interface.7 A fractional dimension testing instrument更多还原