【作者】 丛培良；

【导师】 余剑英；

【作者基本信息】 武汉理工大学 ， 复合材料学， 2009， 博士

【摘要】 大跨径钢箱梁桥面铺装问题一直是国内外工程界广泛关注的问题。环氧沥青混凝土具有优良的高温稳定性、低温抗裂性和抗疲劳性能,是一种较好的钢桥面铺装材料。但是,环氧树脂是极性物质,沥青是非极性物质,两者混合时相容性较差。普通的环氧树脂固化后的脆性高,导致延展性能较差。在桥面铺装应用时,为了提高铺装层抗渗性能,都选用了密级配沥青混合料,这导致了环氧沥青铺装层抗滑性能较差。而且,室内研究时的固化工艺与实际应用时环氧沥青混凝土强度增长工艺存在较大的差异,影响对环氧沥青混合料性能的准确评价。因此,如何改善环氧沥青的相容性、确定合理的室内研究方法、改善环氧沥青混合料级配组成对保证环氧沥青混凝土的铺装质量,提高钢桥面铺装层耐久性具有重要意义。本文在总结国内外环氧沥青铺装材料研究与应用的基础上,采用国产环氧树脂和沥青为原料,通过改善环氧树脂与沥青的相容性,提高环氧沥青的延展性的研究,制备了性能优良的桥面铺装用环氧沥青,通过对环氧沥青混合料的级配组成的优化和合理的实验室内固化工艺的研究,提出了同时具有密实性和抗滑性能的环氧沥青混合料的级配组成及其固化工艺,并研究了环氧沥青的流变特性和混合料的粘弹特性和疲劳特性,主要得出以下结论:1、研究发现表面活性剂可以降低环氧树脂与沥青间的界面张力,改善环氧树脂在沥青中的分散与稳定,使环氧树脂与沥青能够形成均一、稳定的混合物,从而改善环氧树脂与沥青间的相容性;2、将苯乙烯-丁二烯-苯乙烯三元嵌段共聚物(SBS)用于改善环氧沥青的柔韧性,显著提高了环氧沥青的变形适应能力,实现了以普通双酚A型环氧树脂制备出强度高、柔韧性好、热稳定性优良的环氧改性沥青,并明显降低了环氧沥青的成本;3、选用甲基六氢邻苯二甲酸酐(MTHPA)作为环氧沥青固化剂,MTHPA固化的环氧沥青不仅具有固化反应速度慢,使用期较长,利于环氧沥青混合料的施工,而且环氧沥青还具有常温下继续固化的能力,可以保证环氧沥青混合料在铺装后,环氧沥青能够完全固化;4、环氧树脂掺量与改性沥青力学性能呈非线性变化关系。当环氧树脂掺量小于30 wt%时,环氧沥青拉伸强度缓慢增大;掺量大于30 wt%以后,拉伸强度迅速增加;5、环氧树脂对沥青的高温性能改善作用明显。当20wt%环氧树脂加入到沥青中后,沥青PG(Performance Grade)高温等级将提高30℃左右,环氧沥青的复数模量比原样沥青(SBS改性沥青)的复数模量大1～2个数量级;6、在30℃～100℃范围内,环氧沥青的流变特性可以用Arrhenius方程和WLF方程进行描述,环氧树脂加入后可以有效提高沥青在高温条件下的粘弹特性,采用Burgers模型可以较好的描述环氧沥青的粘弹性能,环氧树脂可以明显改善沥青的高温抗变形能力,从而提高环氧沥青混合料的抗车辙能力;7、制备的环氧沥青及其混合料在室内120℃烘箱中养护与室外自然养护时性能的增长趋势存在一定差异,在室内高温条件固化时,力学性能在初始阶段增加缓慢,然后迅速增大;而在室外自然养护时,力学性能随着时间平稳的增大;8、在相同油石比条件下,随着环氧树脂掺量的增加,环氧沥青混合料的马歇尔稳定度和劈裂强度明显增大;环氧树脂掺量对混合料的空隙率、矿料间隙率和沥青饱和度影响较小;9、随着环氧树脂掺量的增加,环氧沥青混合料疲劳寿命明显增大。在设计交通量为1×10~7时,SBS改性沥青混合料抗拉结构强度系数为3.64,掺加20 wt%环氧树脂的环氧沥青混合料的抗拉结构强度系数为1.81,表明采用环氧沥青混合料进行钢桥面铺装时,不仅提高铺装层的高温性能和疲劳性能,而且可以大大降低桥面铺装层的厚度;10、随着环氧树脂掺量的增加,环氧沥青混合料抗变形能力明显增大。分别掺加20 wt%、35 wt%和50 wt%环氧树脂的环氧沥青混合料的总变形分别为SBS改性沥青混合料的40.7%、26.4和21.0%,永久变形分别为SBS改性沥青混合料的45.2%、20.0%和16.1%。更多还原

【Abstract】 An extensively concerned problem in engineering is how to design pavement on long span steel deck. Epoxy asphalt concrete, with better high-temperature stability, low-temperature anti-cracking performance and fatigue resistance, is a comparatively good materials for paving orthotropic steel decks. But there are the obvious differences between asphalt and epoxy resin such as polarity, molecular weight, density, viscosity, solubility coefficient and so on. It leads to low compatibility between epoxy resin and asphalt. Common epoxy resin is a brittle materials and lack ductility after cured. Dense gradation asphalt mixture was selected to pave steel decks for good anti-permanent deformation and anti-water damage. Thus, the paving layer show bad skid resistance. In addition, the processing technology difference between laboratory test and field construction make it is difficult to evaluate the epoxy asphalt mixture performance. Therefor, it is very importance to improve the ductility of epoxy asphalt, the compatibility betweent epoxy resin and asphalt, the curing processing in laboratory, the anti-skid performance of epoxy asphalt mixture, and the durable of paving layer on orthotropic steel decks. The primary goal of the present study is to prepare a epoxy asphalt with better pavement performance using the homemake epoxy resin and asphalt, improve compatibility and elongation at break of epoxy asphalt. Epoxy asphalt mixture with better close-grained and anti-skid performance was prepared by optimizing the aggregate blending and curing processing. And the rheological character of asphalt, viscoelastic properties and fatigue of epoxy asphalt mixture was investigated. The following conclusions are obtained:1. The surfactant was employed to decrease the interfacial tension of epoxy resin/asphalt and improve the compatibility between epoxy resin and asphalt. An epoxy asphalt with better compatibility and homogeneous was prepared.2. The styrene-butadiene-styrene triblock copolymer(SBS) was adopt to improve the flexility of epoxy asphalt. Preparation of epoxy asphalt with high strength, good high-temperature stability and ductility using common domestic diglycidyl ether of bisphenol A epoxy resin and asphalt become reality. And the cost of epoxy asphalt production was reduced.3. Methyl tetrahydro phthalic anhydride (MTHPA) with slow reaction and long using period was employed to prepare epoxy asphalt. It is favourable to pave epoxy asphalt mixture. And the curing reaction of epoxy asphalt occure not only at high temperature but also at room temperature. It is important to assure epoxy asphalt mixture fully cured after paving.4. The relation between epoxy resin contents and mechanical properties is nonlinear. The mechanical properties revealed that the tensile strength increased slowly when the contents of epoxy resin less than 30 wt %. when epoxy resin contents more than 30 wt %, the tensile strength increased significantly.5. The high-temperature performance of apshalt was improved remarkably by epoxy resin. The performance grade at high temperature enhance approximate 30℃when 20 wt% epoxy resin added in asphalt. Compared to SBS modified asphalt, the complex modulus of epoxy asphalt have increased by roughly one or two order of magnitude.6. The relationship of complex modulus and temperature can be charcterized by Arrhenius equal and WLF equal in the temperature range from 30 to 100℃. The viscoelastic of epoxy asphalt was improved by epoxy resin. Burgers model is more suitable for the viscoelastic property research of epoxy asphalt, the model demonstrate that epoxy resin can improve the high-temperature anti-permanent deformance.7. The performance of epoxy asphalt and its mixture showed different trend growth between laboratory curing in oven at 120℃and field curing. The mechanical properties increase slowly in the earliest stages of curing, then increase rapidly. But it is increase steadily throughout the curing.8. Marshall stability and indirect tensil strength increase with epoxy resin contents increasing under the same ratio of asphalt to aggregate. The effect of the ratio of asphalt to aggregate on void, voids in mineral aggregate and voids filled with asphalt is little.9. If the traffic volume in road design was set 1×10~7, the tensile strength structure parameter of SBS modified asphalt mixture is 3.64 and it is 1.81 for 20 wt% epoxy resin modified asphalt mixture. It demonstrated that the high-temperature performance and anti-fatigue of paving layer on steel decks was improved, and the thickness of paving layer was decreased remarkably.10. The deformation resistance of asphalt mixture was improved by epoxy resin. The totall deformation of epoxy asphalt with 20, 35 and 50 wt% epoxy resin is 40.7%, 26.4% and 21.0%, respectively. Compared with SBS modified asphalt, the permanent deformation is 45.2%, 20.0% and 16.1%.更多还原