【作者】 蒋玮；

【导师】 沙爱民；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2011， 博士

【摘要】 目前在城市中,绝大多数的道路、广场都是不透水的混凝土铺装结构。降雨通过城市的排水系统排出,加重了排水系统的负担,暴雨时易引发内涝灾害;此外,密实的路面铺装使渗入地下的雨水大幅减少,地下水得不到补充,形成地表沉陷。为促进路面与环境的协调、可持续发展,创造绿色和谐的人居环境,改善城市道路以不透水铺装为主要路面形式的单一局面,因此对透水沥青路面材料组成与结构功能进行研究。透水沥青混合料(PAC)的细观空隙结构直接影响到混合料的透水性能,采用CT扫描技术,对PAC的细观空隙特征进行描述和分析,揭示了混合料宏观上的材料组成(公称粒径、级配和空隙率)对细观空隙特征的影响规律,建立了空隙率—连通空隙率—渗透系数转换模型和空隙率预估模型;通过设计堵塞试验,评价混合料的抗堵塞性能,并基于细观空隙特征规律进一步解释了造成混合料堵塞的原因和缓解措施。优化了 PAC的材料组成设计方法。级配设计中,基于离散单元方法的虚拟试验结果提出了粗集料粗度概念,分析了粗度同混合料性能的关系,推荐了 PAC级配范围;提出PAC最佳沥青用量确定的新方法,即以15%的飞散损失和0.3%的析漏量作为控制标准,并给出了最佳沥青用量的具体计算公式。通过验证,新方法能够确定合理的沥青用量且更简单、客观。分析评价了 PAC的高温性能、水稳定性、低温性能、疲劳耐久性能和热物理特性,并同密级配沥青混合料有关性能进行比较。浸水汉堡车辙试验结果表明材料组成设计合理的PAC水热综合性能优异;疲劳试验结果表明,随着空隙率的增大,PAC的疲劳性能降低,应力水平变化对疲劳寿命的影响也变得更敏感,合理的油石比条件下,3～10天的浸水不会显著降低疲劳寿命;PAC的热物理指标理论计算和室内模拟试验的结果均表明,PAC热阻性能更好,可阻止和延缓高温季节道路表面的高温向路面内部的传递。根据透水沥青路面的材料特性和适用场合,提出了三种类型透水沥青路面,对各型路面的排水系统进行了设计。通过对透水路面结构的选型以及路面结构层层间结合状态的研究,选取了适当的路面结构设计指标,并采用经历浸水或冻融后的透水路面材料抗压回弹模量进行透水沥青路面结构设计,基于力学分析,推荐了不同交通量条件下各型透水沥青路面的典型结构和合理的结构层厚度。透水沥青路面的各结构层厚度除了应满足路面承载力要求之外,还需要满足透水、排水以及储水等功能需求。为此,分析了降雨在透水沥青路面结构内的流动过程,并基于对降雨参数和降雨过程的分析计算,结合水附着率、连通空隙率、渗透速率等透水路面材料和结构参数,建立了三类透水沥青路面的透水模型和评价体系。更多还原

【Abstract】 At present,majority of highway and square are impermeable pavement structure.Rainfall should be discharged by urban sewerage and drainage system,which will aggravate drainage system’s burden.And rainstorms easily bring waterlogging disaster.Besides that,dense pavements make permeated rainfall substantially reduced,groundwater can’t obtain supplement,and then ground subsidence is formed.To promote the coordination between pavement and environment as well as sustainable development,to create harmonious living environment,and to improve urban roads’ single pavement structure form,this paper researched on permeable asphalt pavement for material fabric and structure function.Permeable asphalt concrete’s micro-pore structure directly affected mixture’s permeability performance.Described and analyzed PAC’s micro-pore characteristics by means of X-ray computed tomography scanning technology,the results revealed the influence law from macroscopic material composition on micro-pore characteristics,and established transformation model among air voids,connected air voids and permeability coefficient,the air voids prediction model was also generated simultaneously.Used pore plugging test to evaluate mixture’s anti-clogging performance,and explained the mixture’s blocking reason combining with micro-pore characteristics,finally put forward mitigation measures.The paper optimized PAC’s material composition design method.During the gradation design,the virtual test results based on discrete element method proposed a new concept about coarse aggregate roughness,then analyzed the relationship between roughness and mixture’s performance,afterwards recommended PAC’s gradation range.In addition,suggested a new optimum asphalt content determining method,which make 15%scattering loss and 0.3%drain-down loss as control standard.This new method even provided a specific calculation formula for optimum asphalt content.After verification,we found the new method can fix a reasonable asphalt content more simply and objectively.Evaluated PAC’s high temperature performance,water stability,low temperature performance,fatigue performance as well as thermal physical characteristics,and compared them with dense-graded asphalt mixture’s relevant performances.The test results of Hamburg Wheel Tracking in water showed PAC with reasonable material composition design own excellent water and high temperature stability.Fatigue test results revealed,with the increase of air voids,PAC’s fatigue performance weakened,and the fatigue life became more sensitive to stress level’s change,but if the asphalt-aggregate ratio is reasonable,3 to 10 days soaking can’t significantly decreased PAC’s fatigue life.Both of PAC’s thermal physical indexes and laboratory simulation test results demonstrated PAC possessed better thermal resistance,who can prevent and delay road’s heat transmission from surface to interior in hot season.According to PAC’s materials properties and applicable situation,put forward three types permeable asphalt pavements,and designed drainage system for every pavement.On the basis of permeable pavement’s structure selection and pavement layers combination state’s research,the author chose appropriate pavement structure design specifications,and adopted mixture’s compression modulus after soaking or freeze-thaw cycle to do permeable pavement’s structure design,finally combining with mechanical analysis,recommended typical structure and reasonable structure layer thickness in different traffic conditions for every type permeable asphalt pavement.Every structure layer thickness of permeable asphalt pavement must be not only satisfy bearing ability,but also fulfill functional requirements as permeable,drainage,water storage and so on.Therefore,the paper studied rainfall’s flow process in permeable asphalt pavement,also analyzed rainfall parameters and rainfall process,on this basis,established three types permeable asphalt pavements’ permeable models and evaluation systems combining with water adhesive rate,connected air voids and permeability coefficient.更多还原