多聚磷酸改性沥青及其复配技术研究

发布时间：2018-03-31 06:36

本文选题：改性沥青　切入点：多聚磷酸(PPA)　出处：《重庆交通大学》2015年硕士论文

【摘要】：用于沥青路面中的胶结料应当提供较好的抵抗低温断裂、高温永久变形的能力,并且在较大温度范围内和交通荷载条件下有良好的耐久性。直接蒸馏所得到的沥青常常并不能直接用于路面中,因此,人们常采用各种方法对沥青做改性处理。化学添加剂中,多聚磷酸(PPA)是较为广泛使用的一种添加剂。在沥青中添加PPA可以提高其抗永久变形的性能,且能够很大程度上解决聚合物改性沥青常见的存储稳定性问题,此外通过将PPA与橡胶粉复配,可以解决传统采用单一胶粉改性的一些问题。本文基于改性机理分析与试验研究,通过不同方面对PPA改性沥青及其与椽胶粉复配形成的胶结料进行了研究。从胶结料的流变特性及沥青的化学组分出发探讨了不同工业等级的多聚磷酸掺量对基质沥青的影响。此外,也研究了橡胶粉与多聚磷酸复配进行沥青改性的效果。结果表明,PPA对沥青质含量较少原油提炼的沥青改性效果不明显。沥青中添加PPA和CR能够进一步提高沥青的感温性能及高温性能。PPA并不会显著降低橡胶沥青的低温性能,采用PPA复合橡胶沥青的改性技术可以抑制采用单一橡胶粉改性由于高温而造成的老化问题。采用多应力蠕变恢复(MSCR)试验研究了多聚磷酸改性沥青的高温性能。测试结果显示,经PPA改性后,基质沥青的蠕变柔量(Jnr)值大幅度得到了降低,提高了抗车辙性能,随着多聚磷酸掺量的增加,恢复率(R)值增加,胶结料的弹性恢复性能提高。通过构造PPA改性沥青的│G*│/sirlδ主曲线以研究PPA掺量,RTPO老化和PPA的工业等级在宽域温度和加载速率范围内对沥青性能的影响。结果表明,随着在基质沥青中添加多聚磷酸,抗车辙性能指标(│G*│/sinδ)在每个试验温度和加载频率下大幅度得到提高。然而,增加的程度受到多聚磷酸掺量,PPA工业等级和老化条件的影响。研究了PPA改性沥青合适的温度敏感性评价指标。结果表明,复数指数(CNI)较好地区分了不同沥青的温度敏感性,可作为多聚磷酸感温性的评价指标。系统地研究了多聚磷酸对基质沥青在热氧老化后物理性能的影响。结果表明,PPA改性沥青的老化反应是一级动力学反应。与基质沥青相比,PPA改性沥青有更高的活化能和较低的老化反应速率。PPA改性沥青的抗老化性能比基质沥青的更好。经济及环境效益分析表明,采用多聚磷酸改性沥青可以降低沥青的改性成本及减少传统改性技术造成的大量温室气体的排放。
[Abstract]:The binder used in asphalt pavement should provide better resistance to low temperature fracture and high temperature permanent deformation, and have good durability in large temperature range and traffic load condition.Asphalt obtained by direct distillation can not be directly used in pavement, so people often use various methods to modify asphalt.Polyphosphate (PPA) is a widely used additive in chemical additives.Adding PPA to asphalt can improve its resistance to permanent deformation and solve the common storage stability problem of polymer modified asphalt to a great extent. In addition, by mixing PPA with rubber powder,It can solve some problems of traditional single rubber powder modification.Based on the analysis of modification mechanism and experimental study, the PPA modified asphalt and its binder mixed with rafter powder were studied in different aspects.Based on the rheological characteristics of binder and the chemical composition of asphalt, the effect of polyphosphoric acid content of different industrial grades on the base asphalt was discussed.In addition, the effect of asphalt modification with rubber powder and polyphosphoric acid was also studied.The results showed that the modified effect of PPA on asphalt with less asphaltene content was not obvious.The addition of PPA and CR into asphalt can further improve the temperature sensitivity and high temperature performance of asphalt. PPA does not significantly reduce the low temperature performance of rubber asphalt.The modification technology of PPA compound rubber asphalt can restrain the aging problem caused by using single rubber powder to modify the asphalt at high temperature.The high temperature properties of polyphosphoric acid modified asphalt were studied by multistress creep recovery test (MSCR).The test results show that the creep compliance of asphalt modified by PPA greatly decreases, and the rutting resistance is improved. With the increase of polyphosphoric acid content, the recovery rate increases, and the elastic recovery property of binder increases.The main curves of PPA modified asphalt were constructed to study the effects of PPA content and the industrial grade of PPA on the asphalt properties in the wide range of temperature and loading rate.The results show that with the addition of polyphosphoric acid to the base asphalt, the rutting resistance (G * / P / sin 未) is greatly improved at each test temperature and loading frequency.However, the degree of increase is affected by PPA industrial grade and aging conditions.The suitable temperature sensitivity evaluation index of PPA modified asphalt was studied.The results show that the complex index CNI can distinguish the temperature sensitivity of different asphalts and can be used as an index to evaluate the temperature sensitivity of polyphosphoric acid.The effect of polyphosphoric acid on the physical properties of base asphalt after thermal oxygen aging was studied systematically.The results show that the aging reaction of PPA modified asphalt is a first order kinetic reaction.Compared with the base asphalt, the PPA modified asphalt has higher activation energy and lower aging reaction rate. The aging resistance of the PPA modified asphalt is better than that of the base asphalt.The economic and environmental benefit analysis shows that the modified asphalt with polyphosphoric acid can reduce the modification cost and reduce the greenhouse gas emission caused by the traditional modification technology.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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