The Effect of Hydrated Lime on the Bond Between Asphalt and Recycled Concrete Aggregates

In this investigation, rolling bottle tests and boiling water tests were performed to evaluate the effect of hydrated lime on the adhesion between recycled concrete aggregates (RCA) and the asphalt binder. RCA from construction and demolition waste (C&DW) were used in this investigation. To generalize the findings, three asphalt penetration grades were analyzed: B40/50, B60/70, and B150/200. The results indicate that the use of hydrated lime does not improve the RCA-aggregate bond. Additionally, the results indicate that a higher asphalt-aggregate adhesion correlates to a lower asphalt penetration grade.     

Molecular investigations on the interactions of graphene,crude oil fractions and mineral aggregates at low,medium and high temperatures

Performance of the nanoparticle-modified asphalt binder is greatly influenced by adhesion properties between asphalt binder and nanoparticle. In this work, the adhesion properties of crude oil fractions (e.g., Saturate, Asphaltene, Resin and Aromatic components of asphalt binder), graphene and mineral aggregates (silicon dioxide) at various temperatures are investigated through molecular dynamic simulation and REAXFF force field. The results from SARA-graphene interface demonstrations that aromatic and asphaltene have 30% higher adhesion properties than saturate and resin. Also, while using graphene is valuable for the adhesion properties of the binder, it has no significant advantage over binder in binder-aggregate interactions.     

Reinforcement effect of fiber and deoiled asphalt on high viscosity rubber/SBS modified asphalt mortar

In this paper we investigate the reinforcement mechanism of high viscosity rubber/SBS modified asphalt mortar mixed with fiber （mineral, lignin or carbon fiber） and deoiled asphalt （DOA）. The softening point, penetration and viscosity tests were conducted to characterize the engineering properties of asphalt-fiber mortar. The microstructure of fiber was observed using scanning electron microscopy （SEM）, and the results indicated that fiber can effectively improve the toughness of asphalt matrix through forming a spatial network structure, and then adhesion and stabilization of asphalt binder. The cone penetration test was designed to study the rheological property of fiber modified asphalt. The results indicated that the reinforcement effect increased with fibers and DOA fraction increasing to a certain threshold, and the optimal fiber content was dependent on the fiber type and its length. Fiber content and filler-asphalt ratio had significant effects on the softening point, penetration, viscosity and cone penetration of asphalt mortar.     

水泥混凝土桥梁桥面防水层现场试验

桥面防水层是桥面铺装结构中非常重要的功能层，不但要起到桥面防水的作用还要保证沥青层与桥面板之间的粘结，目前桥面防水层材料单一、效果欠佳。现场试验研究了两种新型桥面防水层，分别为SBS改性乳化沥青加石屑和SBS改性沥青加预拌碎石，并进行了现场剪切、拉拔试验和经济效益分析。试验结果表明，这两种新型桥面防水层粘结效果优于常规的桥面防水层材料，并且造价合理可行。     

Influence of asphalt chemical composition on moisture susceptibility of asphalt mixtures

To evaluate sensitivity of moisture damage resistance with chemical composition of asphalt, the adhesion energy, debonding energy as well as compatibility ratio of 69 asphalt-aggregate combinations were calculated with thermodynamical models. Pearson correlation analysis and regression analysis were carried out to correlate the relationships between asphalt chemical composition (saturates, aromatics, resins, asphaltenes, and wax) and moisture stability of asphalt mixture. The results showed that more resins and less asphaltenes in asphalt could lead to better moisture stability of asphalt mixture under dry and wet conditions, which can be effectively predicted by multiple regression models with different asphalt chemical components.     

影响粘附性的沥青性质分析

定量测定了沥青各组分与集料粘附性的大小。对沥青酸值、电性能、接触角、合蜡量及粘度与粘附性关系进行了探索。研究结果表明：胶质、沥青质与各种矿料的粘附性最好，而饱和分与矿料的粘附性熏差。施工中为提高沥青路面的抗水损害能力，应选择酸值较大、击穿电压小、蜡含量小及粘度较大的沥青。     

花岗岩沥青混合料水稳定性问题的研究

研究了沥青混合料内部组成对粘附性和水稳定性的影响.从级配、集料、沥青和抗剥落剂的选择角度入手,综合解决花岗岩在沥青路面中的应用.通过对两种典型级配的研究,确定出适用于花岗岩沥青混合料的级配类型;对不同酸性的集料和同种类沥青之间的粘附性试验和冻融劈裂试验,发现集料和沥青之间的粘附是有选择性的.因此,在选择材料时可以优先选择粘附性和水稳定性较好的集料和沥青进行组合;通过不同抗剥落剂对水稳定性的提高程度,确定了最佳的抗剥落剂类型.     

阻燃环保沥青的开发及性能评价

通过向SBS改性沥青中添加无机阻燃剂的方法开发了阻燃环保沥青,并对SBS改性沥青和阻燃环保沥青进行了胶结料和混合料的性能试验。结果表明：阻燃环保沥青的常规性能与SBS改性沥青相比变化不大,而氧指数得到了较大的提高,较好地改进了阻燃性能。对SBS改性沥青及阻燃环保沥青混合料进行了车辙试验、小梁弯曲试验、水稳定性试验等,结果表明：阻燃环保沥青混合料的路用性能与SBS改性沥青相当。同时,模拟燃烧结果表明,阻燃环保沥青有效改善了沥青混凝土的阻燃性能。     

A Study on Xinjiang Asphaltite as an Asphalt Modifier. Part II: Rheological Evaluation of Modified Asphalt Binders

Modified asphalt binders with varying Xinjiang asphaltite contents between 4% and 16% were prepared in laboratory. Dynamic shear rheometer temperature sweep and time sweep tests, bending beam rheometer tests, some conventional tests including penetration and softening point were performed to analyze the rheological properties of these asphalt binders and evaluate Xinjiang asphaltite potential as asphalt modifier. Test results showed with the Xinjiang asphaltite content increasing, complex shear modulus increased and phase angle decreased, which indicated Xinjiang asphaltite could improve the elasticity and deformation resisting of binders. Fatigue failure life of asphalt binders grew exponentially with Xinjiang asphaltite content. Moreover, Xinjiang asphaltite had an adverse effect on the low temperature performances of asphalt binders based on measured creep stiffness and m-value. Based on these test results modification mechanism of Xinjiang asphaltite was analyzed. It is thus suggested that Xinjiang asphaltite is better suitable as a high temperature resistant and anti-fatigue asphalt modifier material.     

磨细废旧轮胎胶粉改性沥青性能及应用

研究了磨细废旧轮胎胶粉改性国产沥青及混合料的路用性能,试验结果表明:在国产AH-70号沥青中掺入10%的磨细废旧轮胎胶粉,可使沥青及沥青混合料的高温、低温性能得到一定的改善;通过试验路施工应用,取得了良好的效果.     

Effects of the Asphalt Penetration Grade and the Mineralogical Composition on the Asphalt-aggregate Bond

This investigation analyzes the loss of bonding between the asphalt binder and the aggregate particles produced by water in hot-mix asphalt pavements. Three asphalt penetration grades were used: B35/50, B50/70, and B160/220. Four different types of aggregates were chosen due to their different expected stripping performances: hornfels, feldspathic schist, gabbro, and dolomitic calcite. To research the loss of adhesion, two laboratory test methods were compared: the rolling bottle method and the boiling water test. The results indicate that a higher asphalt-aggregate bond correlates to a lower asphalt penetration grade. To achieve significant asphalt-aggregate bond improvement, the difference between asphalt penetration grades must be noticeable.     

温拌橡胶沥青桥面防水粘结层的粘结性能试验研究

对比了橡胶沥青在不同温拌剂掺量下的粘度,推荐温拌橡胶沥青中Sasobit温拌剂的掺量为基质沥青质量的3%。采用拉拔试验分别测试了温拌橡胶沥青、橡胶沥青和环氧沥青在0,20,60℃下的粘结强度,对比试验结果发现：相对于橡胶沥青,温拌橡胶沥青在各温度下的粘结强度均有所增强,且温度越高,粘结强度增幅越明显,但均略低于粘结强度优良的环氧沥青。     

躺滴法表征沥青的表面自由能

 表面自由能是用来确定沥青材料自身的黏聚功（黏聚强度）以及沥青与石料之间的黏附功的重要参数。此外,沥青混合料（包括沥青、石料和空气）的水敏感性也可使用沥青与石料的表面自由能参数进行评价。笔者采用躺滴法测定了几种战略公路研究计划(SHRP)沥青与液体的静态接触角,使用Owens-Wendt法确定了沥青的表面自由能。结果表明,躺滴法得到的沥青表面自由能与由接触角得到的数值比较接近,说明可以应用躺滴法来测定沥青的表面自由能。由沥青的表面自由能表征的沥青黏聚能结果与pull-off强度试验结果相吻合。     

Preparation and evaluation of 30# hard grade asphalt

The preparation and evaluation of 30# hard grade asphalt by blending softening point hard deoil asphalt with several soft components were investigated. The results showed that the properties and proportions of blending soft components had a great influence on the properties of 30# asphalt. Chunfeng 70# asphalt and Maoming deoil asphalt were more suitable as blending soft components and their blended asphalt met the technical requirements of GB/T 15180-2010 when the proportion of hard deoil asphalt were 6–12% and 8–16%, respectively. PG grade results indicated that dynamic modulus of 30# asphalts at high temperature increased significantly, and antirutting ability was also improved notably, while the bending resistant ability at low temperature was slightly inferior to the high-grade asphalt. The results of mix performance tests showed that 30# hard grade asphalt had excellent anti–high-temperature deformation ability and preferable water stability compared with high-grade asphalts.     

抗剥落剂TR-500S改善花岗岩混合料路用性能研究

相比于碱性骨料,花岗岩因其显酸性与沥青的粘附性比较差,在载荷、水等因素耦合作用下,混合料过早出现坑槽、松散等病害,严重影响其路用性能。首先通过粘附性试验确定抗剥落剂TR-500S的最佳掺量,然后在此最佳掺量下评价花岗岩混合料的路用性能。试验结果表明:TR-500S受热稳定性良好,能全面改善花岗岩沥青混合料的路用性能,其混合料水稳定性、高温抗变形能力、动态模量、疲劳寿命完全满足沥青混合料的要求,适应重载交通的需要。     

印刷电路板改性沥青流变特性和微观结构的研究

The asphalt modified with different printed circuit boards(PCBs) content(0, 5%, 10%, and 15%) was prepared in this study. The general properties, rheological properties, temperature sensitivity, fatigue resistance, and morphology of the PCBs modified asphalt were investigated by conventional tests, the Brookfield viscometry tests, the dynamic shear rheometer(DSR) tests, the bending beam rheometer(BBR) tests, and the fluorescence microscopy tests. And the influence of PCBs content on the above-mentioned properties was analyzed systematically. The results showed that the addition of PCBs could improve the high temperature performance, the low temperature performance, and the temperature sensitivity property of the modified asphalt, while compromising with the fatigue resistance of the modified asphalt. With the increase of PCBs content, the modified asphalt could have better softening points, viscosity, failure temperature, and temperature sensitivity, while its low temperature performance and fatigue resistance became worse to different degree. And the particle size of PCBs became bigger and non-uniform with an increasing PCBs content. According to the above-mentioned properties, the optimum PCBs content was specified at less than 10% in the modified asphalt system.     

纳米碳酸钙改性沥青及混合料性能研究

对纳米碳酸钙改性沥青及沥青混合料进行了沥青的技术性能试验、沥青混合料的马歇尔试验、高温车辙试验、低温弯曲试验和残留稳定度试验等，结果表明：在沥青中掺入8％的纳米碳酸钙，可使沥青及沥青混合料的高温性能得到明显的改善，且掺加工艺简单方便、价格低廉，值得推广应用。     

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.     

水泥稳定碎石基层上透层油材料的试验分析

为保证水泥稳定碎石基层与沥青类面层之间良好的结合,必须撒布适宜材料的透层沥青。从煤油稀释沥青、普通乳化沥青、高渗透力乳化沥青出发,进行了渗透深度试验、剪切力试验。通过试验对比,提出性能优良的透层油材料,最后对于研制出综合性能优良的透层油具有重要的推广应用价值。     

废旧塑料橡胶复合改性沥青性能研究

鉴于塑料、橡胶改性沥青在国内外成功应用,对新型废旧塑胶复合改性沥青进行性能研究。通过沥青常规试验、DSR试验、BBR试验以及微观观测试验,对其感温性、高温稳定性、低温抗裂性、存储稳定性、抗老化性能等进行评价。研究表明,塑胶复合改性沥青高低温性能满足PG88-28要求,感温性能优于常用的SBS改性沥青,存储稳定性、抗老化性能与其相差不大;通过微观观测试验发现,改性剂与沥青体相互构成立体网状链接结构,是复合改性沥青稳定存在、高低温性能等优越的主要原因。