【作者】 赵鹏；

【导师】 肖庆一；

【作者基本信息】 河北工业大学 ， 道路与铁道工程， 2020， 硕士

【摘要】 “十三五”计划以来,资源节约和节能减排型交通的建设越来越受到重视,沥青路面维修养护过程中产生的废旧沥青材料的应用也变得更加广泛。当前对厂拌热再生沥青混合料的研究中,仍存在较多问题,如旧料掺配率低,混合料路用性能较差等。我国当前沥青路面再生规范中以新旧沥青完全融混为假设,实际上当旧料掺量较高时,新旧沥青并非完全融混状态。因此研究旧料掺量对混合料路用性能及新旧沥青融混状态的影响对提高旧料掺量及混合料的路用性能至关重要。研究首先基于马歇尔设计法对4种旧料掺量(15%、30%、45%、60%)的厂拌热再生沥青混合料及普通热拌沥青混合料进行了配合比设计,验证其高温稳定性、低温稳定性及水稳定性。研究发现,随着旧料掺量提高,再生沥青混合料的低温稳定性及水稳定性逐渐下降,高温稳定性先升高后降低。表明当旧料掺量达到一定较高比例时,再生沥青混合料的各项路用性能均有大幅下降。从混合料回收沥青性能的角度,利用线性振幅扫描试验、动态剪切流变试验、多应力蠕变恢复试验及弯曲梁流变试验对各旧料掺量下混合料回收沥青流变性能进行研究,结果表明,随着旧料掺量的提高,旧沥青含量相对增加,造成了回收沥青的疲劳性能下降,高温抗变形能力提高,变形恢复能力及应力敏感性提高,低温抗裂性能下降。利用原子力显微镜、傅里叶红外光谱、凝胶渗透色谱对混合料回收沥青微观物理化学性质进行研究分析。结果表明,旧料中的旧沥青在与新沥青发生融混后,改变了沥青原有的组分平衡状态,表现为沥青表面粗糙度降低,沥青分子结构中羰基及亚砜基含量增加,沥青中的大分子量增加。沥青的各项微观物理化学性质与沥青的流变性能具有很好的相关性,表明沥青微观结构及分子层面的变化会直接导致沥青流变性能发生改变。最后利用凝胶渗透色谱实验,通过在混合料中添加追踪料,以大分子百分数为指标设计了一种可以定量测定新旧沥青融混效果的方法。结果表明随着旧料掺量提高,新旧沥青融混效果逐渐降低,新旧沥青融混效果与沥青及沥青混合料性能具有很好的相关性,融混效果越低,混合料的路用性能越差。更多还原

【Abstract】 Since the "Thirteenth Five-Year Plan",more and more attention has been paid to the establishment of resource-saving,energy-saving and emission-reducing transportation.The application of recycled asphalt mixture generated during the maintenance of asphalt pavements has become more widespread.However,there are still many problems in the current research on hot mix plant recycled asphalt pavement,such as low content of old materials and poor road performance of recycled asphalt mixtures.In current asphalt pavement regeneration specifications,it is assumed that the new and old asphalt are completely blending.In fact,when the recycled asphalt pavement content is relatively high,the new and old asphalt are not completely blending.Therefore,it is important to study the influence of the content of recycled asphalt pavement on the road performance and the blending effect of the new and old asphalt.Firstly,based on the marshall design method,four ratios of recycled asphalt pavement(15%,30%,45%,60%)of the plant-mixed hot-recycled asphalt mixture and the common hot-mixed asphalt mixture were designed to verify its high temperature stability,low temperature stability,water stability and other road performance.The results show that with the increase of the amount of recycled asphalt pavement,the low-temperature stability and water stability of the recycled asphalt mixture gradually decreased,and the high-temperature stability first increased and then decreased.It shows that when the amount of recycled asphalt pavement reaches a certain high ratio,the road performance of recycled asphalt mixture is worse than ordinary asphalt mixture.From the perspective of recycled asphalt performance,the rheological properties of recycled asphalt in different raito of recycled asphalt pavement were tested using linear amplitude scanning test,dynamic shear rheological test,multi-stress creep recovery test and bending beam rheological test.The research shows that with the increase of the amount of recycled asphalt pavement,the content of old asphalt increases,the fatigue performance of recycled asphalt,the ability to resist deformation at high temperatures increases,the ability to recover from deformation and stress sensitivity increase,and the low temperature crack resistance decreases.The atomic force microscope,fourier transform infrared spectroscopy,and gel permeation chromatography were used to study the micro-physical and chemical properties of the recycled asphalt.The results show that after the old asphalt in the recycled asphalt pavement is mixed with the new asphalt,the original component equilibrium state of the asphalt is changed,and the surface roughness of the asphalt is reduced.,the large molecular amount increases.The micro physical and chemical properties of asphalt have a good correlation with the rheological properties of asphalt,which shows that the change of the microstructure and molecular layer of asphalt will directly lead to the change of the rheological properties of asphalt.Finally,a gel permeation chromatography experiment was used to design a quantitative method for determining the blending effect of new and old asphalt by adding tracer to the mixture and using the percentage of large molecular size as index.The results show that with the increase of the content of the recycled asphalt pavement,the blending effect of the new asphalt and old asphalt decreases gradually.And the blending effect of new and old asphalt has a good correlation with the performance of asphalt and asphalt mixture.The lower the blending effect,the worse the road performance of the mixture.更多还原