【作者】 刘斌；

【导师】 曹东伟；

【作者基本信息】 重庆交通大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 半刚性基层具有强度高、稳定性好、承载力大及抗疲劳性能好等特点,被普遍运用于我国高等级公路的路面结构基层中,但半刚性基层沥青路面在正常运营的过程中容易出现反射裂缝及水损害等病害,影响路面的服务寿命。在沥青面层与半刚性基层之间加铺一层优质密实且具有一定厚度的级配碎石基层,可以有效的缓解半刚性基层沥青路面反射裂缝及水损害等病害,但级配碎石基层的强度及稳定性较差,在行车荷载作用下易产生永久变形。为了有效的提升级配碎石的强度,本文将从级配碎石原材料、配合比、成型方式、添加聚丙烯纤维及施工工艺等环节进行研究。介绍了级配碎石材料的基本力学性能及其影响因素,优化了级配碎石原材料的部分技术指标及级配范围,根据原材料的筛分试验及振动击实试验结果,确定了级配碎石的级配曲线、最佳含水量及最大干密度,并在此级配的基础上,采用重型击实确定了级配碎石的最佳含水量及最大干密度,并用CBR、无侧限抗压强度等试验对其性能进行验证。相比于重型击实,振动击实级配碎石的CBR值提升了 45%左右;对于无侧限抗压强度,重型击实的级配碎石试样无法脱模成型,而振动击实的级配碎石试样无侧限抗压强度可以达到1.02MPa。通过室内大型静三轴压缩试验,对比分析了不同成型方式对级配碎石抗剪强度的影响,试验结果表明采用振动击实可以有效的提升级配碎石的抗剪强度,其中振动击实试样的粘聚力C比重型击实试样的粘聚力C增加了 64%。在振动击实的基础上,将聚丙烯纤维加入级配碎石混合料中,以提高级碎石的强度,并通过劈裂试验确定了纤维级配碎石中纤维最佳掺量为1铅粉。通过CBR、无侧限抗压强度及三轴压缩试验,对比研究了纤维级配碎石与级配碎石的性能,结果表明纤维级配碎石的强度比较高,相比于级配碎石,纤维级配碎石的CBR值提升了 23%左右,抗压强度提升了 13%,粘聚力提升了 36%,因而称纤维级配碎石为高强度级配碎石。为了进一步研究高强度级配基层的路用性能,选用了 4种沥青路面结构进行加速加载试验。在高温(50℃)条件下,对比分析四种沥青路面结构的抗车辙性能,在常温条件下,对比分析了四种路面结构的路面承载力、抗车辙能力及动力响应,试验结果表明高强度级配碎石基层沥青路面的路面承载力及抗车辙能力等性能较好。利用BISAR3.0软件研究分析沥青路面结构各结构层的设计参数对路面结构受力的影响,为高强度级配碎石基层沥青路面的路面结构设计提供合理的理论依据,并提供了相关的设计参考值。通过张家口二秦高速公路中高强度级配碎石基层试验路,对其施工方法进行研究,以确保其基层具有较好的强度及稳定性。研究过程中,对其混合料的拌合、运输、摊铺及碾压等工艺提出了明确的要求;对其基层施工质量的控制,提出了相应的质量控制指标及要求;采用振动搅拌拌合机替代了传统的搅拌拌合机,有效的提升混合料混合的均匀性。更多还原

【Abstract】 Semi-rigid base has been widely used in the base of high grade highway in our country because of its high strength,good stability,high bearing capacity and good anti fatigue performance,However,semi rigid base asphalt pavement in the normal operation of the process is prone to reflective cracks and water damage and other diseases,affecting the service life of the road surface.Between asphalt layer and semi-rigid base paving a graded crushed stone base with a fine-quality,dense and a certain thickness thickness,can effectively alleviate the cracks and water damage of semi-rigid asphalt pavement reflection phenomenon,but the strength and stability of Graded Macadam Base is poor,in the traffic loads is easy to produce permanent deformation.In order to effectively improve the performance of the graded crushed stone,this paper will conduct a comprehensive study on the graded crushed ishihara material,mixing ratio,molding methods,adding polypropylene fiber,construction technology and other aspects.Introducing the basic properties and influencing factors of graded crushed stone materials,optimizing the graded broken ishihara material technical requirements and grading range,according to the raw materials test results of screening test and vibration compaction test,determine the gravel gradation curve,optimum water content and maximum dry density,and based on the gradation,the best water content and the maximum dry density of the graded crushed stone were determined by heavy tamping,and with CBR,lateral compressive tests to verify its performance,test result show that the graded aggregate by vibrating compaction has good performance.Compared to the heavy compaction,vibration compaction of gravel CBR value increased by about 45%;to no lateral compressive strength,the graded crushed stone specimens with heavy compaction can not be demoulding and the no lateral compressive strength of the graded crushed stone specimens with vibration compaction can reach 1.02MPaThrough the indoor static analysis of three axis different molding methods on the shear strength of Graded Macadam stress-strain curve and mechanical technical index compression test comparison,results show that the shear strength of the crushed stone can be improved effectively by using the vibration compaction,in which the cohesion C of the vibrating compaction specimen increases by 64%.On the basis of the vibrating compaction,the polypropylene fiber were added into grading macadam mixture,to improve the comprehensive performance,and through splitting test to determine the optimum content of fiber in fiber graded is 1‰,through CBR,without lateral compression,three axis test performance were studied and results showed that after adding fiber,the CBR value of graded crushed stone was increased by about 23%,the compressive strength was increased by 13%,and the cohesion was increased by up to 36%.In order to further study the road performance of high strength graded base,4 kinds of asphalt pavement structure were selected for accelerated loading test.At high temperature(50 degrees Celsius)condition,comparative analysis of four kinds of anti rutting performance of asphalt pavement,under normal conditions,comparative analysis of the pavement rutting resistance,bearing capacity and dynamic response of four kinds of pavement structure,test results show that the high strength asphalt pavement graded gravel pavement bearing capacity and anti rutting performance are good.Using BISAR3.0 software to analyze the influence of the asphalt pavement design parameters of each structural layer of pavement structure stress,provide a reasonable theoretical basis for the design of pavement structure of asphalt pavement of high strength graded macadam base,and provides a related design reference values.Based on the high strength graded Macadam Base test road of Zhangjiakou Er Qin expressway,the construction method of high strength graded Macadam Base is studied in order to ensure strength and stability of the base.In the course of the study,put forward clear requirements process of mixing,transportation,paving and rolling of mixture,to control the construction quality,put forward the corresponding quality control indicators and requirements,using the dynamic stirring mixer instead of the traditional stirring mixer,which can effectively improve the mixing uniformity of the mixture.更多还原