【作者】 薛忠军；

【导师】 张肖宁；

【作者基本信息】 哈尔滨工业大学 ， 道路与铁道工程， 2007， 博士

【摘要】 目前在旧水泥路面上加铺沥青层是被业内认可的对旧水泥路面进行大修的解决方案。一般加铺层厚度为16-18cm,这个厚度通常会导致沿线桥梁、附属设施的标高要作相应的调整,为此发生的工程费用可能比加铺层本身的工程造价还要高。事实上采用此厚度甚至更厚的沥青加铺层也不会杜绝沥青加铺层裂缝的产生,一味地增加沥青加铺层厚度来防治沥青加铺层裂缝的产生,其效果随着厚度的增加越来越不明显。因此,本文提出了旧水泥路面沥青超薄加铺层综合处治技术的研究课题,研究中综合运用旧路稳定、高性能夹层材料的设计与应用、加铺层结构组合设计等多项技术来防治沥青加铺层裂缝的产生,以达到减薄沥青加铺层厚度的目的,研究的主要内容、成果包括以下几个方面:通过三维有限元分析了影响沥青加铺层稳定的各种因素,分析结果表明沥青加铺层厚度超过一定值对于防治反射的效果已经不明显;高性能夹层的设置可以有效地改善旧水泥路面和沥青加铺层的受力状态;旧水泥路面仍然是承担荷载的主体,其稳定性直接决定了沥青加铺层的寿命;从理论上说明了要实现超薄沥青加铺层需要进行厚度设计、旧路稳定处治和采取防治反射裂缝措施等多种技术的综合运用。旧水泥路面的稳定处治是加铺沥青层的前提,其中水泥板底脱空识别及处治技术是旧路稳定处治的瓶颈问题,本文提出了利用冲击振动声频分析法判断水泥板底脱空的方法,该方法利用共振峰频率等参数作为特征参数,引入Fisher判别函数的方法,建立了水泥板底脱空判别函数,研发了冲击振动水泥板底脱空声频分析仪,开发了相应的脱空判别程序,该技术在多条高速公路的检测中得到应用,并与其它脱空检测技术进行了对比,其脱空识别准确率远远高于目前应用最广泛的落锤式弯沉仪( Falling weight Deflectormeter简称FWD)的脱空识别率;详细总结了注浆施工工艺使其规范化、程序化,提出了浆体流动度等施工质量控制参数。防治反射裂缝的产生与发展是沥青加铺层需要解决的重要技术问题,为此研制了应力吸收防水粘结层(Stress Absorbing Waterproof Interlayer,简称SAWI),研发的过程中发现沥青对SAWI的抗裂性能影响最大,为此研发了高弹性改性沥青,并确定了以3min弹性恢复为重要指标的一系列高弹改性沥青指标及标准;不同的沥青用量、级配类型对应的SAWI性能有所差别,适当比例天然砂的掺入会改善SAWI施工和易性,并会使SAWI的抗裂性能有一个显著的提高,给出了SAWI沥青混合料技术指标建议值。通过改造的沥青路面分析仪(Automatic Asphalt Pavement Analyzer,简称AAPA)模具,评价了旧水泥路面加铺层的整体抗裂性能。试验过程中使用了全程实时、自动录像等手段,为疲劳破坏判别提供了准确的技术支撑,试验结果表明,应用SAWI材料可以有效延长加铺层的使用寿命。进一步对疲劳试验后破坏断面观察发现,加铺层的裂缝仅出现在面层,SAWI层完好无损,这说明SAWI层的使用不仅可以延长面层的使用寿命,而且具有阻断裂缝向下发展的作用,即使在面层出现裂缝的情况下,仍能在很大程度上保持完好,并起到防止水分下渗,保护路面结构的作用。通过稳定旧水泥路面、设置夹层防治反射裂缝等综合技术的应用,使在旧水泥路面上加铺超薄沥青层成为了现实。沥青加铺层总厚度为7cm的超薄加铺层结构已在虎门高速公路、广州一环线等实体工程中得到应用,均取得了预期的效果。更多还原

【Abstract】 Asphalt overlay is an approved way to rehabilitate old cement concrete pavements. To provide enough crack resistance, the thickness of overlay is usually about 16-18 cm. However, many engineering cases proved that even with an enough thickness, the crack resistance is still not satisfying. Besides this, a too large thickness brings a series of abuses, such as heightening the elevation of appurtenant works along the road, then causing the difficulties in joining permanence constructs; reducing overlay rutting resistance performance; increasing construction cost remarkably, and so on. So, this dissertation developed the comprehensive technology of ultra-thin asphalt overlay to rehabilitation treatment existing cement concrete pavement, design and application of high performance interlayer material and combinatorial design of overlay structure to prevent and curing the occurring and spreading of crack, thinning overlay thickness. The main researches were included as following:Three-dimensional finite element analysis all factors of asphalt overlay’s stabilization, the result showed thickness of overlay is little when its thickness exceed certain value; high-powered interlayer can improve stress of slab and asphalt overlay; old slab still support main loading ,the life of asphalt overlay base on the old slab’s stabilization. Synthetically make use of thickness design, old slab stabilization technology and crack resistance technology maybe make ultra-thin asphalt overlay into fact.As one of the bottle-neck questions in existing cement concrete pavement, void identification and treatment technology is deeply studied in this dissertation. Impact vibration frequency domain analysis uses formant frequency as characteristic parameter, imposes“Fisher”function identification method, and establishes identification function for void cement slab. The void identification detection apparatus and program were also developed in the dissertation. This technology was applied in several freeways in cement concrete pavement void detection; and testified with comparison to other void identification technologies, its identification rate is much more veracious than Falling Weight Defectormeter (FWD). Moreover, the study gave a standardized and formalized grouting construction technology; put forward a physical index, slurry flowing degree, as quality controlling parameter during construction. Interlayer physical properties and performance is mainly determined by material. A special material with high mechanical capability and performance, termed as Stress Absorbing Waterproof Interlayer (SAWI) was developed and its influence factors were study. Since bitumen was found is the primary factor for SAWI crack resistance, high elastic modified asphalt and its technological indices (elastic recovery @3Min was invented as an important index for performance evaluation) with standards was given by study. SAWI has different performance with different bitumen contents and/or gradations, adding proper content of sand will not only greatly improve SAWI asphalt mixture in its construction workability, but also increase crack resistance remarkably. After influence factors analysis, a series of SAWI proposal technological indices was given.This dissertation reconstructed patterns of Automatic Asphalt Pavement Analyzer (AAPA), evaluated the integrative crack resistance capability of overlay, and achieved real time auto-video in whole testing process, which provides an technological for identify and observe fatigue damage by rule and line. The test results showed that SAWI interlayer can notable lengthen overlay’s service life. By observing the section of fatigue damaged sample, it can be found that cracks occurred only in surface, SAWI interlayer undamaged, inferred that SAWI effectively interdict cracks developing from top to down and prevent water infiltration, consequently protect the pavement structure out of water aggrieving.In conclusion, this dissertation fulfill ultra-thin asphalt overlay technology on existing cement concrete pavement by analysis ultra-thin overlay structure design theory and feasibility, fix on application conditions, study void identification and treatment for existing cement concrete, interlayer material and overlay integrative performance test methods and facilities. The 7cm thickness ultra-thin asphalt overlay has been applied in Humen freeway, Guangzhou the first loop freeway, and accepted prospective effects.更多还原