沥青混合料低温约束温度应力试验研究

此方法对不同沥青、不同级配沥青混合料的低温抗裂性能作出了评价。试验结果表明，用低温约束温度应力试验中的冻断温度评价沥青混合料低温抗裂性能，直观、可靠性高。不同的沥青品种其混合料冻断温度明显不同，低温性能的沥青抗裂性能较好；沥青品种相同、级配不同的沥青混合料其冻断温度不同，但差别较小。沥青玛蹄脂碎石混合料表现出较好的低温抗裂性，沥青碎石的低温抗裂性较差。     

峡口水库沥青混凝土面板的施工与试验

以灌溉、防洪为主的峡口水库大坝，为沥青混凝土面板堆石坝，为研究低温抗裂性能，对沥青混凝土面板破损取样，进行了配比和多种力学性能试验，并与原面板设计指标进行了对比。由于面板经受住了－20℃以下的低温考验，其所用沥青指标、破损取样试验结果，特别是冻断低温指标，对确定水工沥青混凝土低温抗裂检验标准有重要参考价值。     

纤维沥青混合料低温抗裂性能的研究

采用未切缝试件进行低温3点弯曲试验,评价纤维长度对低温抗裂性能的影响,并分析了纤堆沥青混合料(FRAM)低温抗裂性能的增强机理。研究表明,掺加纤维能有效阻滞裂纹的进一步发展,增强沥青混合料的低温抗裂能力。     

回收沥青混合料掺量对再生沥青混合料性能的影响

研究了回收沥青混合料(RAP)掺量(0%、30%、50%、70%和100%)对热拌沥青混合料最佳油石比、马氏稳定度、抗车辙性能、抗水害性能和抗裂性能的影响。结果表明,RAP降低了新沥青用量,同时RAP在一定掺量下(50%以内),显著提高沥青混合料的马氏稳定度和高温稳定性,并对抗水害和常温抗裂性能基本无负面影响,但是当RAP掺量超过50%后,沥青混合料的高温稳定性、抗水害和抗裂性能大大降低,同时值得注意的是RAP的加入在一定程度上降低了沥青混合料的低温抗裂性能,因此建议RAP的掺量不宜超过50%,并采取一定措施提升混合料的低温抗裂性能。     

高原多年冻土地区SBR改性沥青路面应用研究

针对青藏公路多年冻土地区海拔高、气温低、昼夜温差大、施工周期短的特点，采用SBR改性沥青提高沥青和沥青混合料的低温抗裂性能及抗冻水稳性；通过提高沥青标号，加大沥青用量，解决青藏公路低温开裂这一主要病害。现场试验及大面积铺筑均取得良好使用效果。     

炭黑改性沥青混合料低温抗裂性能的研究

选用国产普通道路沥青,用炭黑作为改性剂对其进行改性。通过一系列的室内研究,发现改性后的沥青及其混合料的低温抗裂性能均优于原沥青,表现出较好的路用性能。     

春风塔河优质道路沥青性能研究

对春风塔河优质道路沥青性质、化学组成进行分析,对其PG分级、混合料性能进行评价。结果表明：春风塔河优质道路沥青四组分构成比例较好,针入度指数适中、软化点和动力黏度（60 ℃）高、低温延度大、蜡含量低、残留针入度比和残留低温延度大;PG分级为PG64-28,感温性好,耐热老化性能优良,抗高温变形、低温抗裂及抗疲劳性能良好,低温抗裂性能尤其突出;混合料性能良好,适合在气候变化大的新疆地区应用。     

SBS-SBR复合改性乳化沥青混合料耐久性研究

SBS改性乳化沥青具有较好的高温性能,并且抗老化和耐疲劳性能也较好,但是低温性能较差,SBR改性乳化沥青低温抗开裂能力很好,水稳定性和耐久性也较好,但是其高温抗车辙性能较差。基于此,制备了SBS-SBR复合改性乳化沥青,并对比其与基质沥青、SBS改性乳化沥青、SBR改性乳化沥青的高温抗车辙性能、低温抗裂性能、水稳定性、疲劳性能,最终得出:SBS-SBR复合改性乳化沥青集合了两种乳化沥青的优势,耐久性有了一定提高。     

布敦岩沥青混合料路用性能研究

通过试验验证了BUTON（布敦）岩沥青混合料的路用性能。利用GTM试验方法对掺加不同掺量布敦岩沥青的混合料进行了配合比设计，得出了最佳油石比和标准密度；并对0、10％、15％、20％掺量的布敦岩沥青混合料的高温抗车辙性能、低温抗裂性能和水损害性能进行了试验研究；结果表明掺加布敦岩沥青后沥青混合料的动稳定度由906次／mm提高到2032次／mm，低温弯曲应变由2050με提高到2940με，冻融劈裂强度比由85．5％提高到98．6％；并且随着布敦岩沥青掺量的增加，路用性能仍继续提高。试验鲒果说明了布敦岩沥青混合料是一种性能优良的沥青混合料。     

废旧胶粉改性沥青混合料低温抗裂性能的研究

本研究主要应用小梁弯拉试验,直接拉伸试验考查了在普通沥青混合料中掺适量废胶粉后对低温抗裂性能的改善效果,并与国内外的优质沥青相比较。     

运用DMA方法研究基质沥青组成对SBS改性沥青黏弹性能的影响

选取4种组成不同的基质沥青制备SBS改性沥青,运用动态力学分析（DMA）方法分析改性沥青黏弹性能。结果表明,采用温度扫描、频率扫描和稳态流动试验得到的改性沥青高温性能具有一致性,基质沥青中芳香分含量是影响改性沥青黏弹性能的主要因素,芳香分含量越高,制备的改性沥青高温黏弹性能越好,饱和分含量过高,会减弱改性沥青内聚力,降低高温黏性。低温弯曲梁流变试验结果表明,胶质和沥青质主要影响改性沥青低温性能,基质沥青沥青质含量过高,改性沥青低温延伸性能越差。     

化学法改性克拉玛依沥青研究

针对克拉玛依沥青难以改性，产品稳定性差等问题，本研究采用化学改性法，对比分析了4种基质沥青在改性前后的元素组成、红外光谱、族组成、分子量的变化以及SBS改性沥青的常规性质的差异。结果表明：相对于物理改性，化学改性不仅显著降低了SBS改性沥青的反应温度，而且还提高了SBS改性沥青的高温性能。     

Characterization of hard-grade asphalt using entropy analysis

By adopting different technologies and raw materials, several kinds of hard-grade asphalts were prepared, and the correlation between performances and chemical compositions for these hard-grade asphalts was investigated based on grey relation entropy analysis. Results indicated that nine types of hard-grade asphalts were in accordance with GB/T 15180-2010 standard for 30# asphalt, although they have obvious differences in the performances. The main factors influencing high temperature performances were the presence of aromatics and resins and molecular weight distribution, while the main factors influencing temperature susceptibility were the presence of saturates and asphaltenes and the unstability of colloids. While there has been slight difference in E_r(X_i) for ductility (10°C and 15°C), the remarkable factors influencing the crack resistance at low temperature (stiffness and m value) were the presence of aromatics and resins and molecular weight distribution, in accordance with high temperature performances.     

CHARACTERIZATION OF SOME IRAQI ASPHALTS I. NUMBER AVERAGE MOLECULAR WEIGHT INVESTIGATION OF DORA AND QAIYARAH ASPHALTS

ABSTRACT

The number average molecular weight (Mn¯) of two Iraqi asphalts has been studied before end after thermal treatment using vapour pressure osmometery. Changes in Mn¯ values after thermal aging were compared with the changes in their physical and mechanical properties. Toluene, benzene, cyclohexane, tetrahydrofuran and carbon tetrachloride were used to fractionate the asphalts The Mn¯ of each fraction was determined before and after aging.     

CHARACTERIZATION OF POLYMER MODIFIED GULF ASPHALTS

The rheological properties of polymer modified Arab asphalts were characterized using both routine test methods, such as penetration and softening point, and more rigorous methods, which included low temperature stiffness measurements using a bending beam rheometer, and dynamic mechanical analysis using dynamic shear rheometer. HP-GPC method of analysis was used to produce profiles of the molecular size distribution of the modified asphalts. Models were built to predict the rheological and performance-based properties from the HP-GPC profiles. The results indicated that polymer modification is capable and effective in improving the neat Arab asphalt binders rheological properties to meet and satisfy the performance requirements of the Gulf countries.     

PREPARATIVE SIZE-EXCLUSION CHROMATOGRAPHY SEPARATION OF SHRP ASPHALTS: CORRELATION WITH YISCOELASTIC PROPERTIES

ABSTRACT

Eight core asphalts and eleven other asphalts selected for study in the Strategic Highway Research Program have been separated into two or more fractions by means of preparative size-exclusion chromatography. The first fraction obtained by this technique is believed to consist of materials that form associations and correspond roughly to asphalt dispersed phases. This phase is polar, aromatic, and of high apparent molecular weight. Subsequent fractions obtained by size exclusion chromatography of the asphalts are of progressively lower molecular weight. When the asphalts were separated into nine fractions, the weights of each fraction were plotted versus elution volume to give distinctive bimodal chromatograms, with one exception.

The first eluted size exclusion fractions consist of the major viscosity-building components of the asphalts. When these fractions are removed from asphalts, the weight fractions of the residual materials correlate with tan δ (ratio of viscous to elastic moduli)s of the whole asphalts at 26° (77°F). Gel-type asphalts have low values of tan δ and large amounts of material in their initially eluted size-exclusion chromatography fractions. For sol-type asphalts, the reverse is true. For the nineteen asphalts studied size-exclusion chromatography fractionation patterns, which are a fundamental chemical property, correlate with the aforementioned fundamental physical property     

CHARACTERIZATION OF POLYMER MODIFIED GULF ASPHALTS

Abstract

The rheological properties of polymer modified Arab asphalts were characterized using both routine test methods, such as penetration and softening point, and more rigorous methods, which included low temperature stiffness measurements using a bending beam rheometer, and dynamic mechanical analysis using dynamic shear rheometer. HP-GPC method of analysis was used to produce profiles of the molecular size distribution of the modified asphalts. Models were built to predict the rheological and performance-based properties from the HP-GPC profiles. The results indicated that polymer modification is capable and effective in improving the neat Arab asphalt binders rheological properties to meet and satisfy the performance requirements of the Gulf countries.     

THE STUDY OF PRODUCING SBS MODIFIED ASPHALT BY USING LIAOSHU HIGH VISCOUS CRUDE OIL

The high viscous crude from Shuguang No.1 zone of Liaohe oilfield has the characteristics of high contents of resin, asphaltene and low wax content, which belongs to low sulfur naphthene-base crude oil and is ideal material for producing high grade paving asphalt. Waste oil used as blender and stabilizer that is rich in aromatics and poor in wax and styrene butadiene styrene (SBS) were added into vacuum residue of the said crude oil. By reasonable process, various brand SBS modified asphalts meeting JTJ036-98 specification were developed. The modified mechanism and road properties were studied. The laboratory test showed these modified paving asphalts had good low-temperature properties and antiaging feature.     

ANALYSIS OF SHHP ASPHALT NONPOLAR FRACTIONS BY SUPERCRITICAL FLUID CHROMATOGRAPHY

ABSTRACT

Three different fractions derived from each of eight SHRP asphalts were analysed by means of supercritical fluid chromatography. The three fractions were a low molecular weight neutral fraction obtained by ion exchange chromatography, a low molecular weight fraction obtained by size exclusion chromatography, end maltenes obtained by precipitation with hydrocarbon solvents. For a given asphalt, these fractions contain much of the same material and all comprise over one-half of the bulk of the asphalts. The ion exchange chromatography neutral fractions contain minimal amounts of polar materials. Based on the microstructural model of asphalt structure, any one of the three fractions might be considered to represent the solvent phase of an asphalt.

The supercritical fluid chromatograms of the asphalt fractions showed that they comprise materials of widely ranging carbon numbers, from 30 to over 110. Chromatograms of all three fractions of each asphalt are similar, particularly the low molecular weight size exclusion chromatography fractions and the maltenes. Chromatograms of fractions derived from different asphalts can differ greatly. The chromatograms of fractions of sol-type asphalts exhibit peaks corresponding to constituents that are more aromatic and of higher carbon number compared with chromatograms of fractions of gel-type asphalts. Thus supercritical fluid chromatography is a useful tool for the investigation of relatively nonpolar fractions derived from asphalts     

THE STUDY OF PRODUCING SBS MODIFIED ASPHALT BY USING LIAOSHU HIGH VISCOUS CRUDE OIL

The high viscous crude from Shuguang No.1 zone of Liaohe oilfield has the characteristics of high contents of resin, asphaltene and low wax content, which belongs to low sulfur naphthene-base crude oil and is ideal material for producing high grade paving asphalt. Waste oil used as blender and stabilizer that is rich in aromatics and poor in wax and styrene butadiene styrene (SBS) were added into vacuum residue of the said crude oil. By reasonable process, various brand SBS modified asphalts meeting JTJ036-98 specification were developed. The modified mechanism and road properties were studied. The laboratory test showed these modified paving asphalts had good low-temperature properties and antiaging feature.