A STUDY ON KINETICS OF AGING OF PAVING ASPHALT

In this paper the aging processes of two penetration-grade paving asphalt which conform to the standard of Esson Company have been studied by rotation thin film oven (RTFO). The first order aging kinetic model has been established and some kinetics parameters were calculated. The relationship between pavement properties of asphalt and aging course was revealed. The intervention of oxygen in high temperature caused oxidation reactions, which changed the composition and structure of asphalt, the aging resistant performance of asphalt was weak, and the service performance went to bad.     

A STUDY ON AGING KINETICS OF ANSHAN PAVING ASPHALT

The aging processes of two Anshan paving asphalts conforming to GB/T15180-94 standard have been studied by Rotation Thin Film Oven Test (RTFOT) and the aging kinetic models of two paving asphalts have been determined. The results show that the aging of the prepared paving asphalt is a first order reaction. The viscosity of the asphalt increases gradually with the aging time. The greater the aging index is, the more easily the asphalt is aged. Because the chains break down to form free radicals, oxidation reactions occur. The aging resistance of the asphalt with lower aromaticity and with less aromatic cycle numbers is weak.     

A STUDY ON AGING KINETICS OF ANSHAN PAVING ASPHALT

ABSTRACT

The aging processes of two Anshan paving asphalts conforming to GB/T15180-94 standard have been studied by Rotation Thin Film Oven Test (RTFOT) and the aging kinetic models of two paving asphalts have been determined. The results show that the aging of the prepared paving asphalt is a first order reaction. The viscosity of the asphalt increases gradually with the aging time. The greater the aging index is, the more easily the asphalt is aged. Because the chains break down to form free radicals, oxidation reactions occur. The aging resistance of the asphalt with lower aromaticity and with less aromatic cycle numbers is weak.     

再生沥青混合料水稳定性能的对比分析

以原样SHELL60—80沥青和对其进行两次不同老化程度后的再生沥青为结合料配制同种级配（AC-16C）的原样沥青混合料和再生沥青混合料，然后对其进行短期老化和长期老化，测试其在三个不同阶段（新鲜阶段、短期老化阶段、长期老化阶段）的水稳定性能，对比分析其的水稳性能，评价再生沥青混合料的抗水损坏能力。     

石油沥青老化性能研究

采用薄膜烘箱（TFOT）在不同时间、不同温度下对五种代表性的沥青进行老化。通过对老化前后沥青的质量变化、针入度比、粘度比、沥青质含量的比较得到了五种沥青在不同条件下性质变化规律,提出了用质量损失表征抗老化性能和用延长薄膜烘箱试验时间模拟长期老化的不适宜性。     

A STUDY ON CHANGE OF FAMILY COMPOSITION AND PROPERTIES OF LIAOSHU PAVING ASPHALT ON AGING

In this paper the change of family composition of the paving asphalt, which conforms to the standard of Sinopec Q/SHR-004-1998, was studied under continuous heating and atmosphere at three different temperatures (150, 163, 180°C), at the same time, the changes of pavement performance were studied. The results showed that at three different aging temperatures saturated hydrocarbon contents did not obviously change after 20 hours on aging. The change of aromatic contents was different before and after 20 hours while resins and asphaltenes contents have changed noteworthily. After aging, resins decreased noteworthily, asphaltenes increased obviously, the composition and structure of asphalt were destroyed which had the pavement performance go bad.     

A STUDY ON CHANGE OF FAMILY COMPOSITION AND PROPERTIES OF LIAOSHU PAVING ASPHALT ON AGING

In this paper the change of family composition of the paving asphalt, which conforms to the standard of Sinopec Q/SHR-004-1998, was studied under continuous heating and atmosphere at three different temperatures (150, 163, 180°C), at the same time, the changes of pavement performance were studied. The results showed that at three different aging temperatures saturated hydrocarbon contents did not obviously change after 20 hours on aging. The change of aromatic contents was different before and after 20 hours while resins and asphaltenes contents have changed noteworthily. After aging, resins decreased noteworthily, asphaltenes increased obviously, the composition and structure of asphalt were destroyed which had the pavement performance go bad.

     

道路沥青老化动力学的研究--以软化点为参数建立沥青老化动力学模型

研究了以辽河油田生产的稠油为基质沥青自制的两种沥青老化后软化点的变化，以软化点为参数建立了沥青一级老化动力学模型。并用该动力学模型对这两种沥青的抗老化性能进行了研究，求得了动力学参数。实验结果表明，这两种沥青老化后软化点均升高，AH-70沥青抗老化性能优于AH-90沥青，以软化点为参数建立的沥青老化动力学模型较好地表征了沥青老化过程，为研究沥青老化提供了一种简便可行的分析方法。     

塔河原油所产道路沥青抗老化性能研究

分析了高沥青质塔河原油减压渣油生产道路沥青的潜在优势和不足,认为主要问题是所产道路沥青的抗老化性能较差和延度较低.研究了塔河减压渣油所产道路沥青的老化过程动力学,结果表明,该道路沥青老化时,活化能较低、反应速率常数较高,老化前后沥青各项指标变化幅度较大,表现出沥青的抗老化性能差.通过对沥青老化机理的分析,认为可采用组分调合、部分改性及添加抗老化添加剂的方法来解决延度低、抗老化性能差的问题.试验数据表明,利用上述方法,可以使塔河原油所产道路沥青的延度和抗老化性能得到改善,主要技术指标符合优质产品规格要求.     

Study on Aging Kinetics of Panjin Paving Asphalt

In this paper, the changes of n-pentane asphaltene content, penetration, softening point, and ductility of two Panjin paving asphalts have been studied during aging. Further, based on the change of n-pentane asphaltene content, a study on aging kinetics of asphalt has been conducted. Some correlative kinetic parameters were calculated, and the aging kinetic equation of asphalt was gained. The value calculated, depending on the equation, was in accordance with the experimental data. In addition, the relationship between the composition of the high grade paving asphalt and its aging resistant performances was revealed. It showed that the aging of high grade paving asphalt was a first order reaction. Moreover, the kinetic model was proved to be reliable by investigating the changes of penetration, softening point, and ductility of asphalt during aging.     

Effect of Chemical Nature on the Susceptibility of Asphalt to Aging

The knowledge of the factors affecting the susceptibility of asphalt to aging can be of help when selecting the asphalt binders for the construction of durable pavements. Investigated were the aging-induced changes in the chemical composition and colloidal nature of asphalts differing in origin and technology. It was shown that the course of the changes in the generic composition of asphalt upon aging under laboratory conditions depends on the chemical type of the feedstock from which the asphalt has been derived. During aging of the asphalts from the paraffin-naphthenic crudes, the resins undergo partial decomposition, which results in the increase of the cyclic fraction content. Although the increase of the asphaltene content in air-blown asphalts after the Thin Film Oven Test was found to be lower than that in the corresponding straight-run asphalts, the much higher value of the instability index and smaller size distribution of asphaltenes in the air-blown asphalts permit us to expect that their utilization as binders in pavement construction will lead to the reduction of pavement durability. It follows from the results of this study that not only the generic composition but also the structure of the fractions affect the resistance of asphalt to aging.     

Effect of Chemical Nature on the Susceptibility of Asphalt to Aging

Abstract

The knowledge of the factors affecting the susceptibility of asphalt to aging can be of help when selecting the asphalt binders for the construction of durable pavements. Investigated were the aging-induced changes in the chemical composition and colloidal nature of asphalts differing in origin and technology. It was shown that the course of the changes in the generic composition of asphalt upon aging under laboratory conditions depends on the chemical type of the feedstock from which the asphalt has been derived. During aging of the asphalts from the paraffin–naphthenic crudes, the resins undergo partial decomposition, which results in the increase of the cyclic fraction content. Although the increase of the asphaltene content in air-blown asphalts after the Thin Film Oven Test was found to be lower than that in the corresponding straight-run asphalts, the much higher value of the instability index and smaller size distribution of asphaltenes in the air-blown asphalts permit us to expect that their utilization as binders in pavement construction will lead to the reduction of pavement durability. It follows from the results of this study that not only the generic composition but also the structure of the fractions affect the resistance of asphalt to aging.     

RTFOT与TFOT对沥青胶结料热老化程度的影响

通过分析老化沥青残留物的质量变化，针久度，粘度，车辙因子和低温蠕变性能，比较RTFOT和TFOT条件下沥青胶结料热老化程度的差异，结果表明：TFOT残留物在常温和高温下的粘度及车辙因子平均水平均低于RTFOT残留物，但低温性能呈现出不同的行为，影响程序取决于沥青品种，当对沥青进行PG分级时，若沥青性能指标接近临界值时，不能忽 视两种老化条件引起的差异，否则容易出现误判。     

沙特中质原油减渣及其丙脱沥青制取高等级道路石油沥青的研究

以沙特中质油的减渣及其丙脱沥青为原料制取高等级道路石油沥青的研究表明,所制取的沥青产品,抗热老化性理想,性能指标在路面使用温度条件下比较稳定,使用性能与国外高等级道路石油沥青相当,符合国内、外有关的技术要求。     

道路用改性石油基彩色沥青的路用性能评价

以克拉玛依优质的低凝环烷基稠油馏分为基础原料，加入填充剂、改性剂等助剂，采用加热搅拌的工艺技术，使各组分很好地熔融为一体，生产出聚合物复合改性的道路用改性石油基彩色沥青系列产品。产品的综合性能超过重交通道路沥青的JTGF40-2004110号A类标准，在关键指标上已达到交通部（JTGF40-2004）的SBS改性沥青I—A标准的要求。对该产品进行的路用性能评价结果表明，所制备的彩色沥青混合料具有良好的水稳定性、高温稳定性、低温抗裂性能和耐紫外线老化性能，各项路用性质满足了彩色铺面的技术要求。     

环氧化SBS改性沥青的粘度及老化性能研究

改性沥青的粘度和老化是影响其路用性能的两个重要因素.试验结果表明,SBS品种、环氧化SBS改性剂的环氧基质量分数和加入量、反应时间以及测试温度等条件都影响改性沥青的粘度.     

Rheological and aging properties of warm mix asphalt binders containing expanded vermiculite

The scope of this study was to investigate the high and intermediate temperature rheological and aging properties of warm mix asphalt binders modified by organo-expanded vermiculites. The rotational viscosity, complex modulus, and rutting parameter (G^*/δ) increased and the penetration and phase angle decreased after modification of 3% organo-expanded vermiculites, indicating that the high temperature rheological properties of the warm mix asphalt binder have been improved. The warm mix asphalt binders containing 3% organo-expanded vermiculites demonstrate the lowest value of phase angle and the highest value of complex modulus compared with the studied binders. In addition, as a result of the rolling thin film oven test, the viscosity aging index of warm mix asphalt binder decreases, while the retained penetration increases obviously with the introduction of organo-expanded vermiculites. The warm mix asphalt binder with 3% organo-expanded vermiculites has more pronounced improvements in aging resistance in comparison with other studied modified warm mix asphalt binders.     

废旧沥青再生剂的实验研究

 根据现代胶体化学的经典理论(DLVO)，研究了沥青的老化机理及废旧沥青的再生机理；根据增溶分散机理、稀释调和机理及蜡晶分散机理对再生剂进行了设计；考察了再生剂各组分对废旧沥青性能的影响及复合再生剂对废旧沥青的再生性能。结果表明，复合再生剂各组分间具有协同效应，复合再生剂对废旧沥青感温性能和高温性能的恢复优于传统的矿物油，3%～5%(质量分数)的加入量会使废旧沥青性能恢复较好。     

苯乙烯焦油对橡胶改性沥青性能的影响

实验以辽河油田生产的沥青为原料,加入橡胶粉和苯乙烯焦油,以高速剪切法制备改性沥青。考察了橡胶粉和苯乙烯焦油对沥青性能的影响,并对改性沥青进行老化实验。确定最佳橡胶粉质量分为15%,并向质量分数为15%橡胶改性沥青中加入苯乙烯焦油,使橡胶粉可在沥青中充分溶胀,提高橡胶沥青的使用性能。实验表明,苯乙烯焦油的加入可提高橡胶改性沥青的性能,此时沥青的软化点可达39.7℃,沥青的针入度可以达11(0.1mm),延度为121cm,符合140号道路沥青标准。老化实验表明,改性沥青老化后橡胶粉有聚结和析出。     

老化对道路沥青温度敏感性的影响

利用薄膜烘箱（TFOT）对两种国产道路沥青进行了不同时间的短期老化，然后使用压力老化仪（PAV）对短期老化后的沥青进行长期老化，对老化前后沥青进行了高温粘度试验，研究了老化对沥青温度敏感性的影响。