冷再生混合料颗粒团强度评价及级配变化研究

发布时间：2018-09-11 16:08

【摘要】：沥青路面冷再生技术可以有效提高资源利用率，保护生态环境，具有显著的经济、社会和环境效益。如今，在沥青路面维修工程中，冷再生技术得以广泛应用。利用冷再生技术对道路进行施工时，，冷再生混合料在压实过程中会发生破碎，导致其级配发生变化，目前对这一问题的研究还较少。本文的研究目的在于通过室内击实试验探讨冷再生混合料在击实前后的级配变化情况，并采用离散元方法分析导致冷再生混合料在压实过程中级配发生变化的颗粒破碎现象。首先，本文对冷再生混合料在室内击实过程中的级配变化进行了研究，发现冷再生混合料颗粒在击实过程中发生了破碎，导致冷再生混合料的级配发生变化，并且颗粒的破碎主要集中在9.5mm～26.5mm的粒径范围；其次，在旧路调查的基础上对旧灰土的劈裂强度进行了测试，并利用PFC2D软件对旧灰土的劈裂强度试验进行了模拟，提出用旧灰土颗粒间的平行粘结强度来对冷再生混合料的颗粒团强度进行评价；然后，采用PFC2D软件建立了冷再生混合料结构层离散元模型，并对其压实过程进行了模拟，发现随着碾压遍数的增多，冷再生混合料中发生破碎的颗粒数目会增多，从而导致冷再生混合料的级配发生变化。最后，提出了冷再生混合料用于二级及以下公路基层时的目标级配范围和一种对目标级配进行修正的措施或方法。并对以水泥石灰为稳定剂的冷再生混合料的抗压强度、劈裂强度、抗压回弹模量和弯拉强度等路用性能进行了研究，结果发现龄期和水泥含量一定时，水泥石灰冷再生混合料的抗压强度、劈裂强度和弯拉强度随石灰含量的增加而减小；水泥和石灰含量一定时，水泥石灰冷再生混合料的抗压强度、劈裂强度和抗压回弹模量随龄期的增长而增大。本文的研究丰富了低等级道路的就地冷再生技术，为冷再生技术施工提供了一定的参考价值，具有一定的理论和实际意义。
[Abstract]:The cold recycling technology of asphalt pavement can effectively improve the utilization rate of resources and protect the ecological environment. It has remarkable economic, social and environmental benefits. Nowadays, cold recycling technology is widely used in asphalt pavement maintenance engineering. When the cold recycling technology is used in the construction of the road, the cold recycled mixture will be broken in the compaction process, resulting in the change of its grading. At present, there are few researches on this problem. The purpose of this paper is to discuss the gradation change of cold recycled mixture before and after compaction through indoor compaction test, and to analyze the phenomenon of particle breakage which leads to the change of intermediate distribution of cold recycled mixture during compaction by using discrete element method. Firstly, this paper studies the gradation change of cold recycled mixture in the process of indoor compaction. It is found that the grain of cold recycled mixture is broken in the process of compaction, which leads to the change of the gradation of cold recycled mixture. Secondly, the splitting strength of the old lime soil was tested on the basis of the old road investigation, and the splitting strength test of the old lime soil was simulated by PFC2D software. It is proposed that the particle strength of cold recycled mixture be evaluated by parallel bond strength between old lime and soil particles, and then the discrete element model of structure layer of cold recycled mixture is established by using PFC2D software, and the compaction process of cold recycled mixture is simulated. It is found that the number of broken particles in the cold recycled mixture will increase with the increase of the number of rolling times, which leads to the change of the gradation of the cold recycled mixture. Finally, the target gradation range of cold recycled mixture and a method to modify the target gradation are put forward. The compressive strength, splitting strength, compressive resilience modulus and flexural tensile strength of cold recycled mixture with cement lime as stabilizer are studied. The results show that the age and cement content are constant. The compressive strength, splitting strength and flexural strength of cement lime cold recycled mixture decrease with the increase of lime content, while the compressive strength of cement lime cold recycled mixture decreases with the increase of lime content. The splitting strength and modulus of compressive resilience increase with the increase of age. The research in this paper enriches the local cold regeneration technology of low grade roads, and provides a certain reference value for the construction of cold regeneration technology, which has certain theoretical and practical significance.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.26;U414

【参考文献】