高模量橡胶改性沥青及其混合料性能研究

高模量沥青及其混合料是解决沥青路面重载交通及长大陡坡路面车辙等问题的重要工程材料。采用活化橡胶颗粒制备的橡胶改性沥青具有优异的高低温性能及抗车辙性能。本文分析了克炼30#A级和克炼50#A级低标号硬质沥青、克炼70#A级沥青及橡胶改性沥青性能,并采用两种级配类型（ATB-25和SUP-20）来评价其高低温性能及水稳定性能。结果表明,橡胶改性沥青PG分级为76-28,在相同温度下,橡胶改性沥青复数剪切模量及车辙因子最大;随着温度的降低,四种沥青的蠕变劲度均显著增大,但橡胶改性沥青的增大趋势最慢,橡胶改性沥青的m值最大;两种级配类型下,橡胶改性沥青具有最大的动稳定度及弯曲劲度模量,同时有较好的水稳定性能。     

废机油残留物再生沥青的抗老化性能

以废机油残留物(REOB)作为沥青再生剂,从REOB自身、REOB再生沥青及REOB再生沥青混合料3个层次进行老化性能研究.通过延时薄膜烘箱老化试验(TFOT)(老化时间分别为5、10、15、20、25 h),测定了REOB再生沥青、RA5再生沥青和基质沥青的质量及黏度变化,并采用弯曲梁流变试验评定3种沥青老化后的低温...     

TB胶粉复合SBS改性沥青及混合料的低温性能

通过小梁弯曲蠕变试验(BBR)以及半圆弯拉试验(SCB),对不同TB胶粉掺量和苯乙烯丁二烯苯乙烯嵌段共聚物(SBS)掺量的TB胶粉复合SBS改性沥青及其混合料的低温性能进行研究,并对其低温性能指标进行相关性分析.结果表明:与基质沥青相比,TB胶粉改性沥青具有优异的低温性能,且随着TB胶粉掺量的增加,其低温PG分级温度下降,沥青低温应力变小,混合料低温抗裂性增强;TB胶粉复合3%SBS改性沥青及其混合料的低温性能高于基质沥青,且随着TB胶粉掺量的增加,其低温性能改善效果较为显著,但低于相应掺量的TB胶粉改性沥青;随着SBS掺量的增加,10%TB胶粉复合SBS改性沥青的低温性能变化不明显,混合料的低温抗裂性变差;TB胶粉改性沥青的低温PG分级可以很好地反映沥青及其混合料的低温性能,而TB胶粉复合SBS改性沥青不能通过单一的PG分级来评价其低温性能,需要结合其他指标共同评价.     

Preparation and rheological characterization of asphalt binders reinforced with layered silicate nanoparticles

Bentonite clay (BT) and organically modified bentonite (OBT) were used to reinforce and modify a bituminous paving asphalt binder. The modified asphalt binders were produced by melt processing under sonication and shearing stresses. The interlayer spacing of silicate layers in bentonite, organically modified bentonite and the modified asphalt binders were analyzed by wide angle X-ray diffraction (WAXD). The softening point, viscosity and ductility of the modified asphalts were tested as a function of clay content and clay type. The dynamic shear rheological tests showed that the modified asphalts have higher rutting resistance. Bending beam rheometer (BBR) test results for aged specimens (through rolling thin film oven (RTFO) and pressure aging vessel (PAV)) indicated that adding BT and OBT can significantly improve low temperature rheological properties and cracking of asphalt.     

Performance evaluation of a high durability asphalt binder and a high durability asphalt mixture for bridge deck pavements

This paper describes the results of laboratory and full-scale performance tests for a high durability asphalt binder (HDAB) and high durability asphalt mixture (HDAM) applicable to the wearing course in a bridge deck system. The HDAB was developed using a styrene–butadiene–styrene (SBS) modifier and hydrocarbon for improving construction workability and resistance to fatigue cracking. Various binder tests were conducted on the HDAB, and test results showed that the resistance to fatigue and low temperature cracking of the HDAB increased significantly compared to that of the PG 64-22 and PG 76-22 binders. For the mixtures, the fatigue test results showed that the HDAM has a three times longer fatigue life than the SBS-modified asphalt mixture. It was also found that the HDAM has a higher resistance against moisture-induced damage. Results from full-scale accelerated testing on the bridge deck pavement system proved that the HDAM can significantly improve pavement performance.     

排水性沥青混合料抗车辙能力及其敏感性分析

采用沥青路面分析仪(APA)对排水性沥青混合料(DA混合料)和SMA混合料进行标准条件和重载交通条件下的车辙试验,采用车辙深度指标分析DA混合料的抗车辙能力及其对加载水平、加载次数及温度的敏感性.结果表明:采用高黏度沥青、适当级配组成并予以充分压实,DA混合料的抗车辙能力可有效提高;DA混合料抗车辙能力对加载水平、加载次数以及温度的敏感性均低于SMA混合料.     

Estimating correlations between rheological and engineering properties of rubberized asphalt concrete mixtures containing warm mix asphalt additive

In recent years, warm mix asphalt (WMA) is widely used for reducing energy requirements and emissions in hot mix asphalt (HMA) industry. In addition, the use of rubberized asphalt in the past has proven to be economical, environmentally sound and effective in improving the performance of pavements across the US and the world. The objective of this research was to investigate the mixture performance characteristics of rubberized warm asphalt mixtures, and their correlation with binder properties, through a series of laboratory tests (e.g., viscosity, dynamic shear rheometer (DSR), and bending beam rheometer (BBR)) conducted on the binders, and obtaining the indirect tensile strength, rutting resistance, and resilient modulus of various mixtures. The results of the experiments indicated that the use of crumb rubber and WMA additive in HMA can effectively improve the engineering properties of these mixes at lower mixing and compacting temperatures and some statistical correlations between rheological and/or engineering properties were developed successfully.     

The effect of crumb rubber modifier (CRM) on the performance properties of rubberized binders in HMA pavements

The application of crumb rubber modifier (CRM) in asphalt mixtures is intended to improve the properties of binder by reducing the binder’s inherent temperature susceptibility. During the interaction with asphalt binder, the CRM particles absorb a portion of the oils in asphalt binder and the particles swell; therefore increasing the viscosity and stiffness of the CRM binder. Still, the performance properties of CRM binders in hot mix asphalt (HMA) pavement are considered to be unclear due to the various interaction effects of CRM with asphalt binders, depending on the CRM percentage, source and size. In this study, a laboratory investigation was conducted on the properties of CRM binders as a function of CRM processing method and percentages. A total of twenty-four CRM binders (3 binder sources * 2 CRM processing methods * 4 CRM percentages) were produced and artificially aged through an accelerated aging process. Evaluation of the CRM binders included the following testing procedures: Viscosity at high temperature, performance properties at high and intermediate temperatures, and cracking properties at low temperature. The results from this study indicated that the higher CRM percentages for CRM binders seemed to lead to a higher viscosity, a better rutting resistance and a less chance for low temperature cracking. In general, the ambient CRM was found to be more effective on producing the CRM binders that are more viscous and less susceptible to rutting and cracking.     

活化胶粉类高粘弹改性沥青超薄罩面应用技术研究

为探究活化胶粉类高粘弹改性沥青混合料在超薄罩面中的适用性,采用车辙试验、小梁弯曲试验、浸水马歇尔试验、冻融劈裂试验等对比高粘弹改性沥青和SBS改性沥青混合料的高温性能、低温性能和水稳定性能,并依托G30线嘉峪关段铺筑试验段。结果表明,相较于SBS改性沥青混合料,高粘弹改性沥青混合料的高温性能提升约70%,水稳定性能提升约20%,低温性能提升约10%,可显著改善路面的服役状况。     

高粘度改性沥青的开发及应用技术

结合排水性沥青路面的性质及特征,介绍了高粘度改性沥青的开发与应用背景,以及技术性能等,同时结合试验研究阐明了该种改性沥青的应用技术及先进性,为进一步推广应用奠定了基础。     

复合式SMA桥面铺装混合料配比设计及高温抗车辙性能研究

为了提升桥面铺装的高温抗车辙性能,采用马歇尔配合比设计方法对3种SMA沥青混合料分别进行级配设计及体积指标验证,选用轮辙试验和车辙试验对所设计的5种复合式SMA桥面铺装结构组合的高温性能评价指标进行测试.结果表明,SMA混合料沥青析漏损失及飞散损失均满足技术要求,SMA具有合理的最大沥青用量,且粘附性良好;提出的5种复...     

高黏改性沥青高温黏弹特性指标区分度分析

为得到能准确区分高黏改性沥青高温性能的评价指标,分别对3种高黏改性沥青(高黏改性剂掺量均为12%)及基质沥青进行滞后环、动态剪切流变(DSR)和软化点等试验,并采用沥青混合料车辙试验进行了验证,基于沥青混合料试验结果对3种高黏改性沥青的高温性能评价指标作了一致性和区分度分析.结果表明:3种高黏改性剂的掺入均可提高基质沥青的黏弹特性和高温性能,但改性效果不同;不同高温评价指标基本能对3种高黏改性沥青的高温性能做出一致性评价,但区分能力不同,其中滞后环试验技术指标和Carreau模型拟合的零剪切黏度(ZSV)值区分度和评价效果最好,而车辙因子和软化点较差.     

胶粉/SBS复合改性高模量沥青混合料性能研究

胶粉/SBS复合改性综合了橡胶沥青和SBS改性沥青的优势,能显著改善混合料的高低温性能。采用残留稳定试验、冻融劈裂试验、低温弯曲试验、车辙试验、四点弯曲疲劳试验和动态模量试验,分析胶粉/SBS复合改性高模量沥青混合料的路用性能及动态力学特性,并与硬质20#高模量沥青混合料及SBS改性沥青混合料进行对比。结果表明,胶粉/SBS复合改性高模量沥青混合料的水稳定性、高低温性能、抗疲劳性能及动态模量值更优,且各项指标满足高模量沥青混合料要求。     

多重应力蠕变恢复试验（MSCR）测定橡胶-SBS 复合改性沥青性能

通过采用剪切流变仪(DSR)对SBS改性沥青、橡胶沥青以及橡胶/SBS复合改性沥青进行多重应力蠕变恢复试验(MSCR),依据ASTM D7405-08对不同改性沥青的Jnr以及Jnr-diff进行了分析。试验结果表明:橡胶-SBS复合改性沥青具有较低的Jnr,具有优异的高温抗变形能力以及较低的应力敏感性,适用于甘肃省高温重载或长陡坡路面修建;MSCR试验也为此类地质气候条件下改性沥青的选择提供了合理的依据。     

河西戈壁地区沥青路面裂缝处治技术应用研究

基于G30连霍高速公路嘉安段养护工程,分析了河西戈壁地区沥青路面裂缝典型类型及成因,提出了设置橡胶沥青应力吸收层后,采用橡胶粉与SBS复合改性沥青混凝土罩面的裂缝处治技术。研究应用结果表明:橡胶粉与SBS复合改性沥青混合料具有优良的低温抗裂性和高温稳定性,在延缓反射裂缝、延长路面使用寿命等方面具有独特的优势。     

不同剂量SBS改性沥青粘度性能分析

介绍了粘度试验的原理,分析了基质沥青和改性沥青的流变指标随温度变化的情况,通过测试基质沥青和改性沥青的粘度,对进一步研究沥青的流变性具有重要意义,同时指出沥青结合料的粘度与混合料的路用性能密切相关。     

Evaluating permanent deformation in asphalt rubber mixtures

Permanent deformation or rutting, one of the most important distresses in flexible pavements, has long been a problem in asphalt mixtures, mainly in countries with high temperatures such as Brazil. Throughout the years, researchers have used different test methods to estimate the rutting performance of asphalt mixtures. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt rubber. Crumb rubber from waste tires introduced into the asphalt is one of suitable application to dispose the tires and used as an additive to enhance the properties of the conventional asphalts. This work aims at comparing the rutting performance of asphalt rubber mixtures (with dense and gap-graded aggregate gradation) with the conventional dense graded mixture most used in Brazil. The asphalt rubber mixtures were produced by the wet process using continuous blend and terminal blend asphalt rubber. To study their performance, two laboratory tests, the Repeated Simple Shear Test at Constant Height (RSST-CH) and the Accelerated Pavement Testing Simulator Test (wheel tracking) were carried out. The testing results confirmed that the use of asphalt rubber binder improves significantly the resistance to rutting. The highest resistance is presented by the mixtures produced with continuous blend binders and gap-graded aggregate gradation. The results of both testing apparatus can be correlated by a linear relationship. The testing results allowed concluding that the characteristics of the asphalt rubber binders cannot be used to predict the permanent deformation resistance of the asphalt rubber mixtures.     

Study on properties of recycled tire rubber modified asphalt mixtures using dry process

To minimize waste tires pollution and improve properties of asphalt mixtures, properties of recycled tire rubber modified asphalt mixtures using dry process are studied in laboratory. Tests of three types asphalt mixtures containing different rubber content (1%, 2% and 3% by weight of total mix) and a control mixture without rubber were conducted. Based on results of rutting tests (60 °C), indirect tensile tests (−10 °C) and variance analysis, the addition of recycled tire rubber in asphalt mixtures using dry process could improve engineering properties of asphalt mixtures, and the rubber content has a significant effect on the performance of resistance to permanent deformation at high temperature and cracking at low temperature.     

Effect of bitumen wax on asphalt mixture performance

This paper mainly deals with waxes which are naturally present in bitumens, and does not include synthetic waxes that sometimes are proposed as bitumen additives. The main objectives were to study the rheological effect of bitumen waxes and the impact of waxy bitumens on asphalt mixture performance, such as rutting, low temperature cracking, and water sensitivity. In the rheological characterisation of bitumens, a dynamic shear rheometer (DSR) and bending beam rheometer (BBR), as well as various conventional methods, were used. For asphalt mixtures, rutting, low temperature cracking and water sensitivity were evaluated by wheel tracking test (WTT), thermal stress restrained specimen test (TSRST), and modified Lottman test, respectively. It was found that, at high service temperatures and within the same bitumen grade, differences in rutting between the asphalt mixtures made with waxy and non-waxy bitumens were relatively small. However, the presence of wax in bitumen resulted in physical hardening at low temperatures. Using waxy bitumens, asphalt mixtures tended to show higher fracture temperature. As regards water sensitivity, no effect of the wax content in bitumen was seen. The water sensitivity was however heavily influenced by type of aggregate and to less extent by bitumen type. The present study implies that the effect of wax on bitumen quality and asphalt mixture performance depends on many factors. Those may include the chemical composition of the bitumen and particularly the nature of the wax.     

高黏沥青改性剂在贵州省干线公路养护工程中的应用

以自主研发的高黏沥青改性剂PEA为研究对象,以日本进口改性剂和某国产品牌改性剂作为平行对比,分别对高黏沥青和高黏沥青混合料的性能进行分析,并铺筑排水沥青路面试验段。结果表明,掺加高黏沥青改性剂PEA制备的混合料路用性能和施工性能优良,具有较好的耐老化性。路面经现场检测,各项技术性能符合《排水沥青路面设计与施工技术细则》(征求意见稿)要求。