【作者】 吕惠卿；

【导师】 张湘伟；

【作者基本信息】 广东工业大学 ， 机械设计及理论， 2008， 博士

【摘要】 论文以国道321线广东高要至封开段水泥混凝土路面改造工程为基础,针对破损水泥混凝土路面修复设计和路面耐久性可靠性等科学问题,进行了较系统地试验和深入的研究。运用统计方法分析了破损水泥混凝土路面断裂破损规律、在试验室研究和配制了新型改性沥青、提出了路面力学性能监测手段、并运用有限元方法分析了破损水泥混凝土路面结构和破损水泥混凝土路面加铺半刚性基层沥青混凝土路面结构中各参数变化对其力学响应的影响,为提高修复设计的可靠性和经济性,提供了新的力学检（监）测方法和改性沥青设计,完善了破损水泥混凝土路面修复设计理论。论文首先对1.2公里长的试验路分块编号,对路面断裂破损状况进行了详细的调查,绘制路面板的断裂平面图,统计分析了断裂位置与行车方向接缝的距离,通过数值分析找到了路面在随机的车辆荷载和环境荷载作用下的断裂规律,研究了其断裂机理,为新建水泥混凝土路面的设计和破损水泥混凝土路面的修复设计提供理论基础。针对破损水泥混凝土路面加铺沥青混凝土路面的反射裂缝问题,基于STRATA应力吸收层的防裂原理,采用环氧树脂和橡胶粉对A级70号沥青进行改性,对加入不同比例和剂量改性剂的改性沥青进行了针入度P_{25℃,100g,5s}、软化点T_R&B和延度D_{25℃,5cm/min}三大指标的试验,同时进行了低温延度D_5℃,5cm/min和扭转回弹试验,在实验室研制出了一种高低温性能较好的改性沥青,以该改性沥青为粘结材料进行了沥青混合料室内试验,验证其具有较好的高温稳定性、抗疲劳性能、抗水损坏性能。针对目前判定路面承载力的主要设计指标路面弯沉的局限性,提出了一种以振弦式应变计为基础新的路面力学性能检（监）测手段。首先将振弦式应变计埋入混凝土梁试件和真实混凝土路面,进行了相关的室内、室外力学试验和室外路面的长期测监测后,验证振弦式应变计在水泥混凝土路面的力学性能测试应用中的可行性;设计了路面力学性能长期无线自动监测系统和人工半自动监测系统,并在试验路段中埋设了振弦式应变计和温度传感器,为破损水泥混凝土路面加铺修复设计的各结构层力学参数性能的测试,路面结构温度场的测试、路面在行车荷载及温度荷载作用下的应变、应力场的长期监测提供了新的方法和手段,为完善破损水泥混凝土路面的修复设计理论和可靠性研究提供新的试验监测方法。论文利用有限元力学分析方法,结合试验路段实际的结构类型和路面调查情况,考虑旧路面结构的实际几何形状,建立了有限元模型,分析了破损水泥混凝土路面板受到不同的边界约束条件、荷载作用在路面不同位置、地基模量、路面厚度、脱空尺寸和行车荷载等因素对路面结构力学响应的影响;同时对试验路不同时期的承载力进行了调查,分析出加速路面破坏的两个重要因素:路肩的稳定和路面结构的排水能力,针对提高破损水泥混凝土修复的可靠性,提出了在修复设计中必须高度重视路肩的维修和路面结构排水能力的修复的观点。论文利用有限元力学方法对破损水泥混凝土路面冲击破碎稳固或灌浆稳固后,加铺半刚性基层沥青混凝土路面结构的力学响应进行了分析。将理论计算结果同埋入路面结构的振弦式传感器所测的应变数据以及贝克曼梁测得的弯沉测量结果相比较,验证了计算模型的有效性和正确性。并以该模型为基础,分析了旧路面厚度、冲击破碎尺寸、行车荷载、温度荷载、加铺基层的厚度、沥青混凝土面层模量等因素对旧水泥混凝土路面加铺路面结构力学响应的影响。本论文理论研究与实验研究的成果已应用321国道试验路段。更多还原

【Abstract】 Based on the reconstruction project of cement concrete pavement (CCP) of the national highway 321 (from Gaoyao to Fengkai in Guangdong province), the major problems in the renovation work were studied. Because of this state, the following were investigated. The crack distribution of the damaged CCP was statistically analyzed. A new type of modified asphalt was prepared and tested in laboratory. An alternative measurement method to determine the pavement mechanical properties was studied. Finally, the mechanical response of the damaged CCP, asphalt concrete (AC) surface and semi rigid base overlay renovation were calculated, and the influence of parameters’ variation on the pavement structure mechanical response was analyzed. In this disertation, the new test and monitoring system and improved asphalt are presented for the improvements in the reliability and economy of renovation work .Futhermore, the renovation design theory of the damaged CCP is enhanced through the mechanical analysis.Initially the pavement slabs in the test road are numbered and pavement crack damage was investigated. The location and size of every crack in each pavement slab was measured and drawn in a plan. Through the statistical analysis of crack distribution in every pavement slab, the average crack distribution of the pavement under stochastic vehicle and environmental load is obtained. The physical mechanisms causing the cracks are discussed. With the crack distribution determined from the analysis, the design theory of new-constructed CCP, as well as of the maintenance and renovation of damaged CCP is developed and improved.One of the key problems in AC pavement overlay on the damaged CCP is the reflective crack. STRATA stress absorbing interlayer is one of the effective solutions. Based on its retarding and resisting reflective crack principle, the A-70 asphalt was modified with epoxy resin and rubber powder. Different samples of the modified asphalt were tested, varying the quality and the proportions of the additives for the penetration index (P25℃,100g,5s), softening point (TR&B) and ductility (D25℃,5cm/min), which are the three basic asphalt property indexes. At the same time, the low temperature ductility D5℃,5cm/min and torsion resilience were also tested. A new type of modified asphalt with good high and low temperature property was prepared at laboratory. Further testing of this modified asphalt mixture was carried out in the laboratory. These experiments demonstrated the good stability under high and low temperature regimes, good anti-fatigue properties and limiting the water-induced damage of the modified asphalt mixture.The present loading bearing capacity index—surface deflection has limitions when different materials was used for the pavement design. A new measurement and monitoring method, based on vibrating wire strain gauges (VWGS), was used for the testing. VWGS were embedded in the laboratory concrete beams and field CCP, then the relative mechanical experiments in and out of doors and long term monitoring in field of the concrete pavement were done. The suitability of the application of VWGS to test the mechanical properties of the CCP is proved by these experiments. Based on the VWGS, long-term automatic wireless and semi-automatic monitoring systems are suggested. The mechanical parameters of various layers of the AC pavement overlay on the damaged CCP can be measured with these VWGS and temperature sensors installed at various depths in the test road. The temperature range and the strain field at different depths in the pavement structure under random traffic and environmental loads are also able to be measured. This system allows for the mechanical response of pavement to be measured and also provides a basis to check on the design and performance of the renovated CCP.According to the actual pavement structure and investigation in the test road, a finite element model was developed, In the model the actual geometrical dimensions of the test road is taken into account. Parameters such as the influence of concrete slab with different boundary conditions, traffic loads at different positions, various ground modulus and surface thicknesses, different void dimensions and traffic load on the response of the damaged CP was calculated and discussed. The bearing capacity of the test road was measured at different time, and then the two important factors accelerating the damage, the stability of the shoulder and the drainage of the pavement structure are obtained. In order to enhance the reliability of the damaged CP renovation, these two factors should be given serious consideration.The mechanical response of the AC and semi-rigid base overlay on the damaged CP was also calculated with the finite element method. The damaged CP is treated by a break & seat procedure or grouting & seat procedure. The comparison between theoretical and measured values are presented, then based on these calculated results and the measured strain and surface deflection results from the VWGS and Benkelman beam, are used to support the validity of the calculation model and method. Using this method, the influence of the old cement concrete slab thickness and the influence of the break dimensions on the mechanical response of the composite pavement, under different traffic and temperature loads, are calculated. The influence of base thickness of the cement concrete slabs that were treated by break &seat procedure, the AC surface modulus and the traffic load on the mechanical response of the composite pavement are further presented.更多还原