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.     

老化对沥青胶结料常规指标的影响

沥青胶结料的老化是影响沥青路面使用性能的一个重要因素，应用旋转薄膜烘箱(RTFOT)对沥青进行短期老化，然后再应用压力老化仪(PAV)对其残留物进行不同时间的老化。对经过不同程度老化的沥青．进行常规的三大指标试验和拈度试验，探讨老化对沥青胶结料常规指标的影响，建立了耦合老化效应的沥青胶结料拈温方程。     

沥青化学组成与其使用性能间的灰熵分析

采用灰色关联熵分析法，分析了沥青化学蛆成与其使用性能之间的关联关系。这种方法克服了灰色关联分析中的不足，这对如何选择再生剂以及确定再生剂加入量都起到了重要的理论指导意义，避免了盲目性。     

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。     

Study and Evaluation of Aging Performance of Petroleum Asphalts and Their Constituents During Oxygen Absorption. II. Chemical Group Composition and Structure Changes

The changes of the chemical group compositions and the structures of Chinese Shanjiasi, Shengli, and Renqiu petroleum asphalts and their constituents during oxygen absorption were successfully studied based on the sample oxygen absorption behaviors. The research results show that every asphalt constituent after absorbing oxygen would change into the near heavier one with the exception of saturates, of which the greatest is the conversion rate of resin into asphaltene. The oxygen molecules absorbed by samples are mainly converted into the oxygen atoms in some oxygen-containing function groups, such as O-H, C=O, and S=O groups. The asphalt colloidal stabilities deteriorate clearly and the molecular weight distributions of asphalts and their constituents spread toward higher molecular weights. The molecular weights of all samples increase gradually after oxygen absorption. Resins and asphaltenes are the more unstable constituents in asphalts as shown by their evident changes after oxygen absorption. The changes of Shengli asphalt and its constituents absorbing more easily oxygen are clearly greater than those of Shanjiasi asphalt and its constituents.     

Study and Evaluation of Aging Performance of Petroleum Asphalts and Their Constituents During Oxygen Absorption. II. Chemical Group Composition and Structure Changes

Abstract

The changes of the chemical group compositions and the structures of Chinese Shanjiasi, Shengli, and Renqiu petroleum asphalts and their constituents during oxygen absorption were successfully studied based on the sample oxygen absorption behaviors. The research results show that every asphalt constituent after absorbing oxygen would change into the near heavier one with the exception of saturates, of which the greatest is the conversion rate of resin into asphaltene. The oxygen molecules absorbed by samples are mainly converted into the oxygen atoms in some oxygen-containing function groups, such as O-H, C=O, and S=O groups. The asphalt colloidal stabilities deteriorate clearly and the molecular weight distributions of asphalts and their constituents spread toward higher molecular weights. The molecular weights of all samples increase gradually after oxygen absorption. Resins and asphaltenes are the more unstable constituents in asphalts as shown by their evident changes after oxygen absorption. The changes of Shengli asphalt and its constituents absorbing more easily oxygen are clearly greater than those of Shanjiasi asphalt and its constituents.     

紫外光老化对沥青化学族组成和物理性能的影响

在较高温度下对两种基质沥青（AH-70、AH-90）进行了紫外光氧老化，研究了紫外光对两种沥青化学族组成和物理性能的影响。结果表明：在紫外光的连续辐照下，两种沥青的饱和分、芳香分和沥青质含量的变化趋势基本相同，即饱和分含量变化很小，芳香分含量明显降低，沥青质含量显著增大，而两种沥青的胶质含量变化有明显差异：AH-70的胶质含量先略微增大后又减小最后基本不变；AH-90的胶质含量先稍微增大而后持续减少，总减少量明显比AH-70多。沥青族组分的变化直接影响其物理性能，在老化过程中，沥青的软化点、针入度和延度的变化与沥青的族组成的变化表现出良好的对应关系。     

沥青混合料水敏感性影响因素的探讨

在室内冻融劈裂试验的基础上,评价以石灰石集料拌制的沥青混合料的水敏感性,分析沥青用量、级配组成和压实度等因素对沥青混合料冻融劈裂强度比TSR的影响。试验与分析结果表明：在组成设计不当和压实度不足的情况下,石灰石沥青混合料也可能出现水稳定性不足的问题。     

沥青感温性指标与沥青组成的灰关联熵分析

沥青的化学组成不同对沥青的物理性能有着不同程度的影响。为了分析这些影响因素的显著性，采用改进的灰关联熵分析法，分析了影响沥青感温性指标的因素，结果表明，这种方法克服了一般灰关联度分析方法的不足，灰熵关联度大小不受分辨系数的影响。影响老化前沥青感温性指标的主要因素是极性芳香分，环烷芳香分，以及中分子尺寸分布和大分子尺寸分布；影响老化后沥青感温性指标的主要因素是沥青的沥青胶体不稳定指数(Ic)和沥青质以及大分子尺寸分布和中分子尺寸分布。     

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.     

反应性SBS改性沥青的研制

以泰州中海沥青为原料，SBS为改性剂，通过加入少量增容剂、偶联剂，采用物理分散、化学改 性的方法研制出反应性SBS改性沥青。反应性SBS必性沥青符合我国JTJ036－1998标准，SBS加入量仅为4％即可达到软化点81．5℃、弹性恢复（25℃）95％以上的良好性能。反应性SBS必性沥青具有良好的热储存稳定性，长期高温储存（163℃，8天）未发生离析。利用荧光显微照相技术研究了反应性和非反应性SBS必性沥青微观结构，结果表明二者的微观结构存在显著差异。     

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.     

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。     

沥青四组分试验方法浅析

在对现行JTJ 052-2000《公路工程沥青及沥青混合料试验规程》"沥青化学组分(四组分)试验"方法中存在的问题进行分析讨论的基础上,提出了修改意见,对完善谈方法有实际意义。     

高速交通条件对沥青路面疲劳性能的影响

在MTS810材料试验系统上进行大量的疲劳试验，综合考虑高速行车时，车辆荷载的增大和作用时间的减小对沥青混合料疲劳性能的影响，探求车辆行驶速度与沥青混合料疲劳性能的关系，以及在高速交通条件下提高沥青混合料疲劳性能的主要措施，研究表明，高速行驶的车辆对路面的疲劳破坏比低速行驶时更加严重，高速交通条件下，轻载车辆对路面的疲劳破坏也不容忽视，为了提高沥青混合料的疲劳性能应该选用粘度较大的沥青和合适的矿料级配，适当增加沥青用量。     

沥青四组分测定条件对结果的影响

沥青的化学组成决定了沥青的使用性能,但是沥青部分物化性能的测定属条件试验,由于在具体试验过程中没有严格按照操作条件进行,导致沥青的化学组成与其使用性能关联性较差.研究通过对比试验,考察了石油沥青组分测定过程中氧化铝的水含量、沉淀沥青质所用溶剂的用量以及冲洗剂的用类等对测定结果的影响.试验结果表明:石油沥青组分测定法是条件试验,改变试验条件将会影响试验的测定结果.     

Effect of Catalysts on Effluents During Air Blowing of Asphalt

Air blowing of asphalt was performed in presence of catalysts. The effluents (distillate) obtained during air blowing were analyzed to see the effect of catalysts on them. This study investigates the effluents in detail, using physical and chemical methods. Catalysts used were metallic chlorides in varying quantities and also in combination with manganese dioxide. The aim of using different catalysts was to develop a suitable catalyst, which can perform hardening of asphalt at par with other available catalyst, at the same time keeping the effluents relatively low and free of acidic gases. These acidic gases decrease the life of the plant and cause environmental problems. During a 15 h air oxidation period, it was observed that for feed I asphalt the physical (specific gravity & viscosity) and chemical (acidity & composition) properties of the effluent oils, were effected by the catalysts. Amount of effluents were different for different catalysts. Saturate contents of the effluent were increased due to catalyst, while naphthalene and polar aromatic decreased. Effluents were free of asphaltene. The variation in the properties of effluents obtained during feed asphalts II and III air blowing, were not so distinct than with feed I. It indicates that the extent of changes in the properties of effluents depends on the composition of feedstock. Effluent oils were investigated by instrumental analytical techniques such as GLC, UV. Some of the properties of blown asphalt are also reported.     

Effect of Catalysts on Effluents During Air Blowing of Asphalt

Abstract

Air blowing of asphalt was performed in presence of catalysts. The effluents (distillate) obtained during air blowing were analyzed to see the effect of catalysts on them. This study investigates the effluents in detail, using physical and chemical methods. Catalysts used were metallic chlorides in varying quantities and also in combination with manganese dioxide. The aim of using different catalysts was to develop a suitable catalyst, which can perform hardening of asphalt at par with other available catalyst, at the same time keeping the effluents relatively low and free of acidic gases. These acidic gases decrease the life of the plant and cause environmental problems. During a 15 h air oxidation period, it was observed that for feed I asphalt the physical (specific gravity & viscosity) and chemical (acidity & composition) properties of the effluent oils, were effected by the catalysts. Amount of effluents were different for different catalysts. Saturate contents of the effluent were increased due to catalyst, while naphthalene and polar aromatic decreased. Effluents were free of asphaltene. The variation in the properties of effluents obtained during feed asphalts II and III air blowing, were not so distinct than with feed I. It indicates that the extent of changes in the properties of effluents depends on the composition of feedstock. Effluent oils were investigated by instrumental analytical techniques such as GLC, UV. Some of the properties of blown asphalt are also reported.     

紫外老化对沥青流变性能的影响

This paper simulated the ultraviolet aging process of asphalt and used dynamic mechanic analysis （DMA） method to evaluate the effect of ultraviolet aging on the asphalt theological properties. After having experienced ultravio- let aging, the low temperature performance of asphalt binder decreased significantly, with its complex modulus increased and phase angle decreased along with changing rheological properties as compared to the performance of original asphalt binder. The ultraviolet aging process would make asphalt binder more sensitive to brittle and fatigue failure. On the basis of the time-temperature superposition principle （TTSP）, the viscoelastic transition frequency （coT） is proposed to evaluate the effect of ultraviolet aging. It is found that with the increase in ultraviolet aging time, the cox moves to the lower frequency range gradually. Since the viscoelastic transition frequency is sensitive to the effect of aging, it can be used as an indicator of ultraviolet aging.     

Study and Evaluation of Aging Performance of Petroleum Asphalts and Their Constituents During Oxygen Absorption. III. Average Molecular Structure Parameter Changes

The changes of the structural parameters of the average molecules of Chinese Shanjiasi and Shengli petroleum asphalts and their constituents during oxygen absorption were studied based on the oxygen absorption behaviors and the chemical group composition and structure changes. The results show that all the structural parameters of the average molecules of asphalts and their constituents increase clearly after oxygen absorption with the exceptions of the naphthene carbon rates and the paraffin carbon rates. The parameters include the total carbon numbers, the aromatic carbon numbers, the naphthene carbon numbers, the paraffin carbon numbers, the total ring numbers, the aromatic ring numbers, the naphthene ring numbers, the total hydrogen numbers, the aromaticities, and the concentration indexes. The most obvious are the structural parameter changes of the average molecules of the asphalt resin and asphaltene constituents. The structural parameter changes of the average molecules of Shengli asphalt and its constituents are remarkably greater than those of Shanjiasi asphalt and its constituents. The clearer changes of all the average molecular structure parameters of SHL asphalt resin and asphaltene, especially resin could possibly be one of the key factors leading to the much clearer deterioration of the colloidal stability and the serviceability than SJS asphalt in oxygen absorption.