沥青的酸值对沥青混合料水稳定性的影响

沥青与石料的粘附性好坏直接影响沥青混合料的耐久性。如果沥青选择不当且不掺外加剂，就很难得到稳定的沥青混合料。为此，探讨了不同性质的沥青对混合料水稳定性的影响，并提出了满足沥青混合料水稳定性指标的沥青酸值范围。酸性石料组成的混合料，必须对沥青进行改性处理后才能满足水稳定性要求。中性石料组成的混合料，当沥青酸值＞３．２ｍｇＫＯＨ／ｇ时，能满足抗水害要求；当沥青酸值＞３．５ｍｇＫＯＨ／ｇ时，混合料间接抗     

超声波技术用于测量沥青和石料的粘结性能

1 引言 沥青混合料的水损坏在整个美国已引起沥青路面的严重破坏,增加了路面的维修工作。沥青路面水损坏的形式及程度与坏境、石料、沥青及沥青混合料有关。沥青混合料最普通的水损坏形式是沥青从骨料上脱落下来。沥青与骨料的初始粘结能力是影响沥青混合料使用性能的主要因素之一。有关此类问题的研究工作是SHRP计划的一个组成部分。     

大空隙沥青混合料配合比设计研究

大空隙沥青混合料是指空隙率在15%以上的间断沥青混合料，其具有优良的使用性能，但常规的马曷尔试验已不适用来进行配合比设计。本研究在严格控制目标空隙率的基础上，采用流淌试验和磨耗试验相结合的方法确定了大空隙沥青混合料的配比，同时对大空隙沥青混合料的高温稳定性，水稳定性以及透水性进行了研究。表征本研究提出的方法是一种简单易行的方法，与密级配沥青混凝土相比，大空隙沥青混合料具有高的高温稳定性，水稳定性和透水性。     

聚酯纤维沥青混合料的试验及应用研究

聚酯纤维沥青混合料在江苏省已得到较大规模的应用。东南大学交通学院陈光伟博士通过掺加纤维和未掺加纤维的沥青混合料的水稳定性、高温稳定性、抗低温开裂等对比试验分析，研究了聚酯纤维沥青混合料的路用性能。对聚酯纤维沥青混合料作了简单经济分析。结合江苏省聚酯纤维沥青混合料的应用情况，提出了施工中的技术要点。研究表明，聚酯纤维沥青混合料具有良好的路用性能。聚酯纤维沥青混合料可作为江苏省解决沥青路面车辙问题和延长沥青路面使用寿命的技术选项。     

硅藻土改性沥青混合料水稳定性的试验研究

将硅藻土掺配在沥青混合料中，可以改善沥青混凝土的性能，提高路面工程的质量。使用冻融劈裂试验，采用不同剂量的硅藻土来研究硅藻土对沥青混合料水稳定性能影响。试验结果表明硅藻土能较好地改善沥青混凝土水稳定性能，其最佳剂量为15％。     

沥青混合料水损害的室内研究

在级配确定的基础上选取对沥青混合料水稳定性有影响的几种典型因素:集料种类、沥青种类、空隙率、老化程度掺加抗剥落剂种类等,通过正交试验,以一次冻融劈裂强度比、多次冻融劈裂强度比作为沥青混合料水稳定性的评价指标。通过室内试验,定量地探讨了这些影响因素各个水平变化所引起的对沥青混合料水稳定性的影响;采用正交试验极差分析法分析试验数据,最后得出了如下结论:对于沥青混合料水稳定性能,影响最大的因素是沥青种类,剥落剂种类及集料种类次之。     

硅藻土改性沥青及其混合料路用性能研究

对硅藻土改性沥青及其混合料进行了一系列室内试验研究，包括沥青的技术性能试验，沥青混合料的高温车辙试验，低温弯曲劈裂试验，残留稳定度和冻融劈裂试验以及弯曲疲劳试验。研究结果表明硅藻土能改善沥青的高温、低温和抗老化性能；且硅藻土改性沥青混合料能显著提高混合料的水稳定性、低温性能，高温稳定性和抗疲劳性能，具有良好的路用性能，是一种值得推广的改性沥青混合料。     

掺配基质石油沥青的环氧沥青混合料稳定耐久性研究

为获得经济节约且服役性能优良的环氧沥青材料,将环氧沥青(EA)与基质石油沥青进行调配,对不同基质沥青种类与掺量的混合环氧沥青(MEA)混合料进行配合比设计,采用低温弯曲试验、高温车辙试验、冻融劈裂试验、浸水马歇尔试验评价MEA混合料的温度稳定性与水稳定性。研究表明,基于弯曲应变能密度临界值角度分析,基质石油沥青的掺入使得MEA混合料的低温抗裂性能得到改善;MEA混合料具有优异的高温稳定性与水稳定性。     

水泥对乳化沥青冷再生混合料性能的影响

研究了水泥在乳化沥青冷再生混合料中的作用机理,评价了不同水泥用量对乳化沥青冷再生混合料性能的影响,包括工作性能、高温性能、低温抗裂性能、水稳定性能和无侧限抗压强度。研究结果表明,水泥的加入从整体上有效地提高了再生混合料的力学性能、水稳定性和高温稳定性,有效地提高了乳化沥青冷再生混合料的路用性能。     

掺加消石灰的沥青混合料抗水损害性能试验研究

结合盐通高速公路实际情况，采用冻融劈裂试验方法，对中上面层沥青混合料中添加消石灰、液体抗剥落剂进行了水稳定性试验比较，比较结果表明掺加消石灰后对改善沥青混合料的水稳定性有很明显的效果。根据研究结论，在盐通高速公路中下面层全线进行了推广，其长期应用效果将继续跟踪观测。     

MODEL STUDIES AND INTERPRETIVE REVIEW OF THE COMPETITIVE ADSORPTION AND WATER DISPLACEMENT OF PETROLEUM ASPHALT CHEMICAL FUNCTIONALITIES ON MINERAL AGGREGATE SURFACES

Moisture-induced damage in petroleum asphalt pavements, which results in a loss of pavement tensile strength, is a significant contributor to pavement performance problems such as rutting, shoving, flushing and cracking. Results of the present study provide fundamental information on some of the chemistries of moisture-induced damage. Model compounds containing polar chemical functional group types found in asphalts were used to simulate the adsorption-water displacement characteristics of asphalt molecules on mineral aggregate surfaces. A comparative and interpretative discussion of the model compound studies and earlier studies on actual asphalt-aggregate mixtures is presented. Carboxylic acids were confirmed as the functional type most strongly adsorbed on most mineral aggregate surfaces; however, they were also the functional type most easily water displaced. Pyridine-type functionality similar to that found in asphalts reduced the sensitivity of asphalt-aggregate mixtures to moisture damage. Results suggest that prior treatment of aggregates with antistripping agents rather than their prior addition to the asphalts should improve the moisture resistance of mixtures. The reaction of carboxylic acids with aggregate surfaces prior to the reaction of the aggregate surfaces with pyridine-type functionality greatly increased the sensitivity of the pyridine types to displacement by water. Also, the reaction of pyridine with carboxylic acid functionalities prior to their adsorption on aggregate surfaces also increased their sensitivity to water displacement. Results of the model compound studies provided further interpretation of the results of earlier fundamental studies on the adsorption and water displacement characteristics of actual asphalt components from aggregates typically used in paving mixtures. Results are interpreted with regard to their usefulness in finding pragmatic solutions to pavement pavement moisture damage problems. Further needed research is also suggested.     

微生物对沥青集料间粘附作用的影响

沥青混合料的剥离是沥青路面几种常见破坏现象之一。通常认为沥青混合料水稳性主要依靠沥青与集料间的粘附程度，它同沥青集料间的物理化学作用密切相关。本文分析了微生物对沥青集料粘附作用的影响，这对改善沥青路面水稳性有重大意义。     

Influence of Fly Ash on the Properties of Asphalt

Abstract

In this study, we investigated fly ash replacement of the fine aggregate in hot-mix asphalt concrete mixtures. Fly ash was obtained from the Soma thermal power plant. Fly ash in amounts of 5, 6, 7, and 8% by total aggregate weight was added as an additive to asphalt concrete mixtures. Mixtures were prepared without additives containing filler, which had the same percentages as the fly ash mixtures, and briquette samples were prepared from mixtures with fly ash and with filler. Marshall tests were applied to the samples, and optimum asphalt contents were determined. In the optimum conditions, parameters were determined, which were stability, practical specific gravity, void, flow, and max theoretical specific gravity. The results indicate that the stability values obtained from mixtures with fly ash are higher than mixtures from filler. The highest stability value was obtained from 5% fly ash added mixture, which was 1,630 kg in optimal conditions.     

Adhesion of Recycled Concrete Aggregates,Demolition Debris,and Asphalt

In this investigation, rolling bottle tests and boiling water tests were conducted to evaluate the effect of different fillers and treatments on the adhesion between recycled concrete aggregates (RCA) and asphalt. The test results when 100% RCA loose mixtures were evaluated indicated that the filler that achieves the best asphalt aggregate bond was grey Portland cement. Curing the mixture in an oven for 4 h at mix temperature before compacting and coating RCA with bitumen emulsion are treatments that achieved satisfactory adhesion results as well.     

矿料级配及空间分布对混合料性能的影响

为了了解沥青混合料中矿料自身几何特性、分布及混合情况对混合料性能的影响,利用有限元方法构建单多颗集料模型并探究其力学特性,之后模拟三种特定沥青混合料结构进行分析对比,最后优化级配曲线。结果如下：胶浆与集料的交界面上易出现应力极值及损伤;集料间垂直距离对等效应力的影响大于水平距离;与骨架～空隙结构相比,骨架一密实结构、悬浮一密实结构抗剪性能与承栽性较好;AC－13最佳级配曲线在规范级配中值下方,颗粒偏粗。结果表明矿料中集料的细观力学特性决定沥青混合料的宏观承载能力,为更好地研究沥青混合料内部不均匀性引起的力学行为提供了新的思路。     

A STUDY OF LOW TEMPERATURE HARDENING ON THIN FILM ASPHALT BINDER IN CONTACT WITH AGGREGATE SURFACE

The interaction between asphalt and aggregate surfaces before and after low temperature storage (reversible and/or irreversible) at various film thickness was investigated by means of the sliding plate geometry with standard Pyrex glass plates and machined aggregate plates. Significant differences in behavior of asphalts in contact with aggregate plates have been observed, especially at low shear rates. One asphalt shows substantial aggregate surface-induced structuring while another shows essentially none. Moreover, the study of the film thickness effect on the rheological properties of asphalt binders and asphalt aggregate mixtures show that thin films of asphalts on an aggregate surfaces have substantially changed rheological properties from bulk asphalt properties and further, physical properties in thin films are not easily predicted from bulk properties. In addition, the study of storage and setting in thin films of asphalts on aggregate surfaces indicates that oxidative aging occurred after long-term storage (5 months) at room temperature of 25°C. Infrared spectroscopic analytical results on asphalt binders show that sulfoxide and ketone form during storage. It is interesting to note that the molecular structuring effect in asphalt-aggregate mixtures could be partially eliminated by heating to a temperature above 100°C for a short period of time (20 seconds). The results also show that the aggregate surface-induced structuring as well as the asphalt composition contribute to the long-term storage hardening of asphalt-aggregate mixtures at low temperature.     

SEAM沥青混合料高温稳定性影响因素的灰关联熵分析

通过车辙试验.分析了掺入SEAM的AC-13沥青混合料高温抗车辙性能的影响因素,并运用灰关联熵分析法对SEAM掺量、沥青针入度、沥青当量软化点、沥青用量、4.75 mm筛孔通过率、沥青混合料空隙率等影响因素进行分析。研究表明,SEAM掺量、空隙率和沥青当量软化点对SEAM沥青混合料高温稳定性有重要影响。     

A STUDY OF LOW TEMPERATURE HARDENING ON THIN FILM ASPHALT BINDER IN CONTACT WITH AGGREGATE SURFACE

ABSTRACT

The interaction between asphalt and aggregate surfaces before and after low temperature storage (reversible and/or irreversible) at various film thickness was investigated by means of the sliding plate geometry with standard Pyrex glass plates and machined aggregate plates. Significant differences in behavior of asphalts in contact with aggregate plates have been observed, especially at low shear rates. One asphalt shows substantial aggregate surface-induced structuring while another shows essentially none. Moreover, the study of the film thickness effect on the rheological properties of asphalt binders and asphalt aggregate mixtures show that thin films of asphalts on an aggregate surfaces have substantially changed rheological properties from bulk asphalt properties and further, physical properties in thin films are not easily predicted from bulk properties. In addition, the study of storage and setting in thin films of asphalts on aggregate surfaces indicates that oxidative aging occurred after long-term storage (5 months) at room temperature of 25°C. Infrared spectroscopic analytical results on asphalt binders show that sulfoxide and ketone form during storage. It is interesting to note that the molecular structuring effect in asphalt-aggregate mixtures could be partially eliminated by heating to a temperature above 100°C for a short period of time (20 seconds). The results also show that the aggregate surface-induced structuring as well as the asphalt composition contribute to the long-term storage hardening of asphalt-aggregate mixtures at low temperature.     

Properties of asphalt binder and asphalt concrete containing waste polyethylene

In this study, the effects of addition of waste polyethylene on asphalt binder and asphalt concrete mixture properties were studied. Four asphalt concrete mixtures (each mixture containing different percentages of shredded polyethylene material) were prepared and tested as per Indian specifications. Shredded polyethylene and hot asphalt binder were added to heated aggregate (in same sequence) until all aggregates were coated. The loose mixtures were compacted and tested for its mechanical and volumetric properties. Furthermore, compacted specimens were aged for short- and long-term conditions. The extracted binder from the aged and control mixtures was tested for its rheological properties using a dynamic shear rheometer. Mixtures containing shredded polyethylene showed improvement with respect to the Marshall strength, flow, and volumetric properties. The properties of recovered asphalt binder indicated that the addition of polyethylene improved complex modulus values and decreased phase angle values over range of frequencies.