【作者】 刘慧；

【导师】 王立久；

【作者基本信息】 大连理工大学 ， 市政工程， 2010， 博士

【摘要】 根据沥青混合料的组成结构,从力学角度出发,提出了沥青混合料的力学强度模型,该模型很好地解释了嵌挤骨架型沥青混合料的强度组成机理。通过对球体颗粒的堆积填充特性的分析,以填充理论为基础,计算出了三维模型下骨架型集料控制筛孔的大小为0.277D。根据粗、细集料的架构效应和填充作用的不同,推导出了嵌挤骨架型沥青混合料集料中粗集料用量、细集料和填料用量的理论计算公式。根据理论计算公式计算出了文中所研究的20种不同级配的粗集料用量为72.5%,与前人研究结论基本一致。借鉴沙庆林院士SAC级配计算公式的思想,将粗集料看作一个整体,将细集料和填料看作一个整体,基于Fuller理论和分形理论,对嵌挤骨架型沥青混合料集料级配进行了研究。推导出了以Fuller理论为基础的粗集料级配的设计公式、细集料和填料级配的设计公式,以及以分形理论为基础的粗集料级配的分形公式、细集料和填料级配的分形公式。当3-XC=nC.3-XF=nF时,基于Fuller模型集料级配设计公式与沥青混合料集料的分形公式相同,但其表示的意义不相同。二者意义不同,但计算结果一致,进一步说明了该模型的可行性。把细集料单独作为一个整体,对规范中给定的级配范围进行线性回归,得到不同结构类型混合料细集料的分形维数范围：AC13为2.43～2.56,Sup13为2.28～2.54,SMA13为2.66～2.88,SAC13为2.54～2.73。与把粗细集料作为一个整体与把细集料单独作为一个整体时相比较,AC13细集料的分形维数取值范围的差别不大,但是骨架型混合料的细集料分形维数差别较大。对于骨架型沥青混合料,粗集料级配设计时以形成骨架为目的,细集料级配以密实填充粗集料空隙为目的,二者侧重范围不同,故其参数也应该不相同。所以用同样的方法研究二者的级配参数,思路是不正确的,结果也会存在一定误差。利用VCADRF骨架初级检验方法对合成的20种不同的级配组合进行了初级检验,利用压碎试验骨架检验法对4种不同的粗集料级配进行了骨架检验。VCADRF骨架初级检验方法和压碎试验骨架检验法的结论基本一致,粗集料形成了骨架结构。在设计最佳沥青用量时,嵌挤骨架型沥青混合料的骨架作用在马歇尔荷载方式下得不到充分体现,故在确定最佳沥青用量时在马歇尔试验的基础上,引入了抗压强度和抗拉强度两力学性能指标。对于悬浮密实型沥青混合料,两种方法确定的最佳沥青用量相差很小。对于骨架型沥青混合料两种方法确定的最佳沥青用量相差较大。研究表明,该力学性能指标能够很好地反映嵌挤骨架型沥青混合料的强度性能,方法可行。同时这两个参数的引入,为实现路面结构与材料设计一体化奠定了基础。通过嵌挤骨架型沥青混合料的抗压强度、抗拉强度、抗剪强度计算值、高温性能、低温性能及水稳定性的分析,建议nC取值范围为0.4～0.6,也即是粗集料的分形维数XC值取2.4～2.6；nF取值范围为0.30～0.35,也即是细集料的分形维数XF值取2.65～2.70。更多还原

【Abstract】 Based on the composites structure of asphalt mixtures, strength models are suggested from mechanics view. Those models primly explain the strength mechanism of interlocking skeleton asphalt mixture.Through the analysis on packing and filling characteristics of the sphere particles, the primary control sieve is calculated to be 0.277D in the three-dimension models based on the filling theory. For interlocking skeleton asphalt mixture, theoretical formulae of the dosage of coarse aggregates and the dosage of fine aggregates and fillers are presented in terms of the different frame effects and filling actions of coarse and fine aggregates. The dosage of coarse aggregates of twenty aggregate gradations is 72.5% by the theoretical formulae, which is in good agreement with others’ studies.Referencing the formulae of SAC aggregate gradations suggested by Sha Qinglin academician, coarse aggregate in the asphalt mixture is regarded as a whole research object and fine aggregate and fillers a whole research object. The aggregate gradations of interlocking skeleton asphalt mixture are researched based on the Fuller theory and fractal theory and the formulae of coarse aggregate gradation and fine aggregate and fillers gradation are respectively obtained. When 3-XC=nC and 3-XF=nF, the formulae obtained from the two different methods are same, but their significance are different. This testifies the feasibility of the models.Regarding fine aggregate in the asphalt mixture as a whole research object, fractal dimensions range of the samples were obtained by linear regression and listed as AC 13 is 2.43～2.56, Sup13 is 2.28～2.54, SMA13 is 2.66～2.88 and SAC13 is 2.54～2.73, through analyzing the fine aggregate gradation scales from Standards. In some published literatures, coarse aggregates and fine aggregates were investigated integrally, however, the gradations types were neglected sometimes. In the dense gradation mixture, there are little differences between fractal dimensions of the coarse and fine aggregates but it makes sense for skeleton asphalt mixture. For the asphalt mixtures with skeleton structure, coarse aggregates gradations are designed to form skeleton structure but fine aggregates gradations designed to fill the voids formed by coarse aggregates. The objectives are different, therefore their fractal dimensions would be different. It is inappropriate to investigate the coarse and fine aggregates in a skeleton asphalt mixture by the same method.Twenty varied aggregate gradations are tested with VCADRF method and the four coarse aggregate gradations are tested with crush testing method. The results of two methods are in good agreement, which proves that coarse aggregates form the skeleton structure. In the optimum asphalt content design, skeleton structure function of the coarse aggregates in the interlocking skeleton asphalt mixture is not adequately embodied under the Marshall load, so the compressive strength and tensile strength are introduced into Marshall method. The optimum asphalt content determined by the two methods are slightly different for suspending-dense asphalt mixtures but it makes sense for skeleton structure asphalt mixtures. It is shown that the strength performance of interlocking skeleton asphalt mixture can be adequately embodied and the method is applicable. Moreover, the adoption of the two mechanical parameters lays a foundation for the realization pavement structural and material design incorporating.By analyzing the compressive strength, tensile strength, calculated values of shear strength, high temperature performance, low temperature performance and moisture susceptibility of interlocking skeleton asphalt mixture, the value of nC is recommended as 0.4～0.6 and the value of nF is 0.30～0.35. In other words, the fractal dimensions of coarse aggregates Xc is 2.4～2.6 and the fractal dimensions of fine aggregates XF is 2.65～2.70.更多还原