新疆地区沥青高温疲劳性能指标评价

以新疆地区常用的四种沥青为例,运用动态剪切流变试验分析沥青短期老化前后车辙因子随温度的变化规律,用以评价沥青的高温性能及疲劳性能。试验结果表明:SBS(I-C)改性沥青的高温性能优于其他品种沥青,但它的疲劳性能需关注,橡胶沥青的高温性能及疲劳性能均较优。     

废旧橡胶粉掺量对橡胶沥青高低温及疲劳性能影响研究

为分析橡胶粉掺量对橡胶改性沥青高低温及疲劳性能的影响,选取三种橡胶粉掺量(16%、20%及24%)对基质沥青分别改性。对不同掺量下的橡胶沥青进行动态剪切流变(DSR)及弯曲梁流变(BBR)试验,并与基质沥青及SBS改性沥青对比。试验结果表明,橡胶沥青的高温性能优于基质沥青及SBS改性沥青,低温性能虽不如SBS改性沥青,但强于基质沥青。至于疲劳性能,试验表明当橡胶粉掺量为20%时,其疲劳因子最低,疲劳性能最优。     

橡胶沥青高温性能对比研究

为了对比研究橡胶沥青的高温性能,通过动态剪切流变试验和重复蠕变试验测试了现场湿法橡胶沥青、资源集约型橡胶沥青和SBS改性沥青的高温流变性能。根据试验结果,分别采用车辙因子和重复蠕变试验中的Burgers模型黏性部分、累积变形增长率、累积变形、残留变形百分率评价沥青胶结料的高温性能。试验表明橡胶沥青的高温性能均优于SBS改性沥青;资源集约型橡胶沥青的高温性能优于现场湿拌橡胶沥青。此外,采用重复蠕变试验指标更能有效评价橡胶沥青的高温性能。     

资源集约型橡胶沥青加工工艺研究

为了研究剪切时间和剪切温度等生产工艺,以及胶粉用量、化学添加剂等对橡胶沥青性能的影响,分别改变生产工艺和胶粉及添加剂用量,制备橡胶改性沥青,并研究其基本性能指标。主要研究结论如下:随着剪切时间的延长,黏度先增大后减小,针入度逐渐增大,延度先增大然后基本保持不变,软化点基本不变,离析值变小。随着加工温度的升高,针入度明显增大,软化点降低,从而降低了其高温性能。随着胶粉掺量的增加,体系的黏度增大,限制了沥青体系的流动性,同时针入度减小,延度下降。交联剂含量的增加能够减小离析值,提高改性沥青的高温贮存稳定性。活化剂使胶粉与沥青两者的相容性提高,降低了改性沥青的耐感温性能和耐老化性能,但是高温储存稳定性得以改善。综合工艺以及配方设计等研究成果,通过掺加胶粉25%,硫化剂0.5%(占胶粉含量),活化剂0.3%,在180℃,4 000 r/min的剪切乳化机中剪切45 min,可制备高温贮存性能良好的资源集约型橡胶沥青。     

微波胶粉比表面积对橡胶沥青流变性能的影响

通过考察不同微波辐射时间对胶粉活化处理并制备胶粉改性沥青的效果,研究微波辐射对胶粉表观特性与其改性沥青流变性能的影响。采用气体吸附仪、动态剪切流变仪分别测定胶粉活化前后的比表面积及改性沥青的流变性能,并将胶粉的比表面积与沥青流变性能进行关联。在此基础上,结合扫描电镜,从微观角度揭示活化胶粉对沥青流变性能的影响机理。结果表明:在测定时间内,微波辐射使得胶粉表面变得蓬松,孔隙增多,比表面积增长显著;一定时间范围内(60～120s)的微波辐射对胶粉改性沥青的高温抗车辙能力有显著影响;胶粉微波活化后其比表面积与改性沥青流变性能之间有很好的相关性,胶粉比表面积越大,其复数剪切模量越大,相位角越小,沥青的高温抗变形能力越好。     

发育时间对橡胶沥青性能的影响研究

制备了不同发育时间的胶粉改性沥青样品,并通过动态剪切流变仪（DSR）和弯曲梁流变仪（BBR）等对其进行分析。用得到的高温指标（黏度、软化点、车辙因子等）和低温指标（延度、蠕变劲度）分析发育时间对胶粉改性沥青性能的影响。结果表明：胶粉改性沥青样品的高温性能和低温性能均较好;但随发育时间的增加,高温性能和低温性能有所下降,温度敏感性变大,胶粉和沥青的相容性变好,热储存稳定性变好。     

纳米粉体改性沥青的流变性能分析

为了研究纳米二氧化钛对沥青的改性效果,对不同纳米粉体掺量的纳米改性沥青进行不同时长的高压汞灯照射,模拟沥青经过紫外光照射所造成的老化,然后在高温条件下通过多应力重复蠕变试验对不同掺量及不同老化程度改性沥青的流变性能进行分析,试验发现纳米粉体掺量为1.5%～2.5%时沥青表现出良好的高温性能以及抗紫外老化能力。     

胶粉目数对胶粉改性沥青流变性能的影响研究

以胶粉改性沥青为研究对象,掺入相同比例(20%)、不同细度的胶粉颗粒对基质沥青进行改性,得到4种胶粉改性沥青:20目改性、40目改性、60目改性和80目改性。试验结果显示:(1)胶粉改性沥青的高温性能、低温性能、抗剪切性能、自愈性能等普遍好于基质沥青;(2)胶粉改性沥青的贮存稳定性低于基质沥青;(3)胶粉数目对改性沥青60℃黏度、175℃黏度、黏韧性和韧性的影响欠规律,为胶粉改性沥青的应用和推广提供技术支持。     

发育时间对橡胶沥青性能的影响

制备了不同发育时间的胶粉改性沥青样品,并通过动态剪切流变仪(DSR)和弯曲梁流变仪(BBR)等对其进行分析。用得到的高温指标(黏度、软化点、车辙因子等)和低温指标(延度、蠕变劲度)分析发育时间对胶粉改性沥青性能的影响。结果表明:胶粉改性沥青样品的高温性能和低温性能均较好;随发育时间的增加,胶粉和沥青的相容性变好,热储存稳定性变好,但温度敏感性变大,说明高温性能和低温性能有所下降。     

白炭黑/橡胶复合改性沥青及其混合料路用性能研究

为研究白炭黑材料对橡胶沥青的复合改性效果,基于不同类型、掺量的白炭黑复合改性沥青,通过对其进行技术性能试验、流变性能试验、老化性能试验以及混合料试验,并采用针入度体系指标、175℃黏度、车辙因子、老化残留物性能以及混合料性能指标为评价依据,对其胶结料性能与混合料性能进行分析,结果表明:沉淀法制备的白炭黑对橡胶沥青的改性效果较好,掺加白炭黑进行复合改性能进一步提高橡胶沥青的高温稳定性能,其软化点涨幅可达15%、175℃黏度与车辙因子也随着白炭黑掺量显著提高,掺加适量白炭黑后复合改性沥青的抗老化能力提高,其中TFOT老化后残留物的针入度比涨幅可达22%,并且掺加白炭黑后复合改性橡胶沥青混合料的车辙动稳定度、马歇尔残留稳定度以及劈裂强度比(TSR)都显著提高,综合表明掺加白炭黑进行复合改性能有效提高沥青及其混合料的稳定性与耐久性。     

Evaluate thermal cracking resistance of asphalt binder using 4-mm dynamic shear rheometer monotonic test

This study was conducted to evaluate the thermal cracking resistance of asphalt binder using monotonic test by 4-mm dynamic shear rheometer (DSR). The asphalt binder used in this study was extracted and recovered from four field sections of Rochester experimental pavement in Olmsted County, Minnesota. Fracture energy and failure strain obtained from the stress–strain curve were found to be potentially good indicators to investigate low-temperature performance of asphalt binder. It was observed that the fracture energy and failure strain correlate well with transverse thermal cracking in the field. The frequency sweep test to determine shear modulus and the bending beam rheometer (BBR) test to determine the creep stiffness and m-value were conducted to verify the test result.     

High-temperature performance of gilsonite-modified asphalt binder and asphalt concrete

This article investigates the effect of addition of gilsonite (natural bitumen) to asphalt binder on its rheological behavior at high temperatures through construction of complex modulus (G*) master curve using dynamic shear rheometer (DSR) test. This impact is further investigated by evaluation of performance of asphalt concrete modified with gilsonite at elevated temperatures using repeated dynamic creep test. The results showed that introduction of gilsonite to asphalt binder increases its stiffness and elasticity. Also, the results indicated that the modification of asphalt concrete with gilsonite improved rutting resistance significantly.     

PHYSICAL PROPERTIES OF ASPHALT-RUBBER BINDER

This study was performed to determine how the rheological properties of asphalt-rubber binders are affected by various parameters. Properties studied were asphalt composition, rubber dissolution, and the low-, intermediate-, and high-temperature rheological properties, measured with the bending beam rheometer. dynamic shear rheometer, and rotational viscometer, respectively. The rheological properties of the asphalt-rubber binder were determined to be dependent on the rubber content (weight percent), rubber particle size, and base asphalt composition. By controlling these variables, an asphalt-rubber binder with improved low-temperature cracking resistance, improved mid-temperature rutting resistance and temperature susceptibility, and a non-detrimental high-temperature compaction viscosity, all relative to the base asphalt, can be produced.     

A Study on the Performance and Storage Stability of Crumb Rubber-Modified Asphalts

Abstract

Crumb rubber–modified asphalt (CRMA) with good storage stability was prepared using activated crumb rubber. The activation of crumb rubber was carried out by blending crumb rubber with polymeric compatibilizer in extruder to improve interaction between crumb rubber and asphalt. The softening point difference (SPD) and photomicrographs were used to reveal the storage stability of CRMA. The long-term storage stability test results indicate that the softening point difference of CRMA was below 2.5°C. The rheological characteristics of the binders were studied with a dynamic shear rheometer (DSR) and a bending beam rheometer (BBR). The results showed that the CRMA binders are possessed of the better resistance to permanent deformation at high temperature and cracking at low temperature than those SBS-modified and straight-run asphalts.     

PHYSICAL PROPERTIES OF ASPHALT-RUBBER BINDER

ABSTRACT

This study was performed to determine how the rheological properties of asphalt-rubber binders are affected by various parameters. Properties studied were asphalt composition, rubber dissolution, and the low-, intermediate-, and high-temperature rheological properties, measured with the bending beam rheometer. dynamic shear rheometer, and rotational viscometer, respectively. The rheological properties of the asphalt-rubber binder were determined to be dependent on the rubber content (weight percent), rubber particle size, and base asphalt composition. By controlling these variables, an asphalt-rubber binder with improved low-temperature cracking resistance, improved mid-temperature rutting resistance and temperature susceptibility, and a non-detrimental high-temperature compaction viscosity, all relative to the base asphalt, can be produced.     

Rheological properties of Deurex – modified WMA binder containing SBS

Recently, warm mixture asphalt (WMA) technologies drawn much attention for their benefits to environment and workability. Deurex is novel type of warm mixture asphalt additive, which is extracted from sugar cane. The objective of this study is to experimentally investigate the effect of Deurex on SBS modified asphalt. The Deurex was blended into SBS modified asphalt at the dosages of 2%, 3% and 4%. Physical properties tests including penetration, soft point and ductility, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests were carried out. The test results showed that the increase in Deurex additive could significantly reduce the viscosity of SBS modified asphalt, which indicates that the Deurex can serve as an effective type of warm mixture asphalt additive. In addition, the results showed that the addition of Deurex can enhance the high temperature properties while lower the low temperature performance of SBS modified asphalt. However, as long as the Deurex dosage is not higher than 3%, the low temperature grade of WMA binder keep the same as the control binder.     

Characterization of ductility of field-aged petroleum asphalt

This study evaluated the ductility properties of sixty-nine different types of asphalt extracted from the field projects using dynamic shear rheometer (DSR) monotonic and oscillation test. These extracted asphalts were subjected to field aging. The ductility of asphalt mixture was also characterized by indirect tensile test. It was found that test temperature had effect on property measurement. Failure strain measured at 5°C from monotonic test correlated well with DSR function measured from oscillation test. Both higher failure strain and lower DSR function indicated a better ductility of asphalt, and were also indicative of ductility of asphalt mixture. Failure strain would be potentially used to separate polymer-modified asphalt from non-polymer-modified asphalt.     

Effect of chlorination on the assessment of waste engine oil modified asphalt binders

The main objective of this study is to develop a new asphalt binder using waste engine oil (WEO) and improve its properties especially the resistance to rutting, reduces thermal susceptibility as well as the solubility in kerosene. The properties of WEO binders were modified further by chlorine. All blends were evaluated using Fourier transform infrared (FT–IR) spectroscopy, Thermal gravimetric analysis (TGA) differential scanning calorimetry (DSC) and dynamic shear rheometer (DSR). Asphalt binder specimens containing different concentrations (0, 2, 4, 6, and 8) % of waste engine oil with and without chlorine gas were fabricated.     

Investigate the physical and rheological properties of asphalt binders modified with barium sulfate nanoparticles

Abstract

The aim of this study is to investigate the physical and rheological properties of modified asphalt binders with barium sulfate (BaSO₄) nanoparticles. The penetration grade test and the softening point test on the controlled and modified asphalt binders showed that the presence of nanoparticles improved the physical properties of asphalt binders. Dynamic shear rheometer (DSR) test was performed on the main and modified asphalt binders in unaged and short-term aged modes. The asphalt binders containing 2% of nanoparticles in each of the unaged and short-term aged modes have the maximum value of rutting parameter at all temperatures.     

沥青软化点温度下的粘弹特征

本文对30余个沥青样品进行了动态剪切扫描试验,探讨了软化点环境下的沥青的粘弹性状态。试验发现：在软化点温度条件下,纯沥青与改性沥青处于两种不同的流变状态,石油沥青粘弹组成中粘性分量居多,相位角多在80o以上;而SBS改性沥青则保持较低的模量值和相位角,弹性仍保持为一个明显的特质。同时,利用Shapiro-Wilk正态检验发现,在a=0.05置信水平下,不管老化状态如何,纯沥青软化点对应一个稳定的复数模量,在荷载100Pa、频率10rad/s的实验条件下,该模量均值为13033.7Pa,标准差为2104.7Pa。并利用这种等模量规律求取纯沥青的软化点,证明了与实测软化点的良好关联性。需要更多数据以验证本文的初步结论。