Enhancing the performance of blown asphalt binder using waste EVA copolymer (WEVA)

Air blowing of asphalt generally decreases the penetration value of asphalt binder so that asphalt becomes more brittle and more susceptible to crack during thermal cycling. The aim of this study is to improve the elasticity of blown asphalt upon blending with 3%, 5%, and 7% by weight of thermoplastic waste EVA copolymer (WEVA). Physico-chemical characteristics of blended samples like (FTIR and TGA) were discussed. In addition, the physical properties including penetration test, softening point, ductility test, and elastic recovery were studied. The chemical constituents of asphalt binder including oils, resins, and asphaltenes fractions were investigated using solvent extraction technique. Also, the flow properties of dynamic viscometer at different shear rate were also measured. Moreover, the mechanical properties including storage modulus, tan δ, and stress relaxation were analyzed with dynamic mechanical analyzer at temperature range (20 °C–80 °C). The sample blended with 5%WEVA demonstrated an enhancement in storage modulus and elastic recovery and decrease in tan δ. Finally the prepared blends were applied on carbon steel panel, the paints showed an improvement in properties such as flexibility, hardness and drying times with good adhesion. The overall results approved that blending with 5 wt% (WEVA) improve the performance of blown asphalt binder.     

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.     

Rheological Evaluation and Modeling of Sasobit®-Modified Asphalt Binder at High Temperatures

Warm mix asphalt using Sasobit® (Sasol Wax Company, Sasolburg, South Africa) is a new technology to reduce construction temperatures of asphalt mixes. This article presents the rheological properties of Sasobit-modified asphalt binder at high temperatures using response surface methodology. The results showed that the temperature at which the asphalt binder was blended with Sasobit had no effect on the high-temperature properties of Sasobit-modified asphalt binder, including viscosity and viscosity–temperature susceptibility, at each aging state. All empirical viscosity and aging models of Sasobit-modified asphalt binder follow second-order polynomial trends with test temperature, Sasobit contents, and their interactions at each aging condition.     

Rheological properties of graphene/tourmaline composite modified asphalt

Abstract

The purpose is to improve performance of asphalt by synergistic enhancement of graphene and tourmaline. Graphene/tourmaline composite modified asphalt was prepared. The basic properties and rheological properties of graphene/tourmaline composite modified asphalt were analyzed systematically. The results indicate that the basic viscoelastic properties of asphalt were not destroyed after graphene/tourmaline composites added into asphalt. The rutting resistance of graphene/tourmaline composite modified asphalt was superior than tourmaline. And the larger the composite material content, the superior the rutting resistance of modified asphalt. The rutting resistance was increased by 10.12%.     

Evaluation of rutting resistance of asphalt binders and asphalt mixtures modified with polyphosphoric acid

In this research, a polyphosphoric acid (PPA) additive was used to modify a performance graded binder (PG 58-22). Experimental program included use of three PPA contents (0.5%, 1%, and 1.5%) by weight of bitumen and use of antistripping limestone aggregates. High-temperature rheological properties of asphalt binders were evaluated through the frequency sweep test. Complex modulus test was also used to evaluate rutting characteristics of asphalt mixtures. Results showed that PPA significantly improved rutting resistance of both unmodified asphalt binder and unmodified asphalt mixture, especially for the asphalt binder.     

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。     

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.     

A statistical analysis on the mechanical properties of nanocomposite modified asphalt mixtures

This study aimed to characterize the rate of change that takes place in the mechanical properties of polymer-nanocomposite asphalt (PNMA) mixtures due to altering asphalt binder grade and styrene-butadiene-styrene (SBS) type. Laboratory testing program included Marshall stability, resilient modulus, and wheel-tracking tests. Test results were compared and analyzed statistically by means of two-way analysis of variance and Tukey test. Variance analysis indicated the significant effect of both binder type and SBS grade on mechanical properties of asphalt mixtures. Interaction between binder type and SBS grade is also meaningful in all the experiments. The results also show that the binder type is the primary affecting factor, followed by the SBS grade.     

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.     

橡胶沥青的动态剪切流变试验分析

通过动态剪切流变试验,对路用橡胶沥青结合料的流变性能进行了分析。试验采用2种不同类型的基质沥青以及4种不同含量的胶粉制备成5种不同类型的橡胶改性沥青,使用动态剪切流变仪分别对原样、短期老化以及长期老化三种状态的试样进行了测试,分析了各粘弹性参数随橡胶沥青类型变化的规律。同时也对比分析了各种类型的胶粉改性沥青的高温抗车辙性能和抗疲劳性能。试验结果表明,橡胶胶粉含量在15%～21%范围内时,橡胶沥青的高温和中等温度下疲劳性能均随橡胶胶粉含量的增加而提高。     

Rheological and aging properties of warm mix asphalt binders containing expanded vermiculite

The scope of this study was to investigate the high and intermediate temperature rheological and aging properties of warm mix asphalt binders modified by organo-expanded vermiculites. The rotational viscosity, complex modulus, and rutting parameter (G^*/δ) increased and the penetration and phase angle decreased after modification of 3% organo-expanded vermiculites, indicating that the high temperature rheological properties of the warm mix asphalt binder have been improved. The warm mix asphalt binders containing 3% organo-expanded vermiculites demonstrate the lowest value of phase angle and the highest value of complex modulus compared with the studied binders. In addition, as a result of the rolling thin film oven test, the viscosity aging index of warm mix asphalt binder decreases, while the retained penetration increases obviously with the introduction of organo-expanded vermiculites. The warm mix asphalt binder with 3% organo-expanded vermiculites has more pronounced improvements in aging resistance in comparison with other studied modified warm mix asphalt binders.     

Thermal and rheological properties of nanoparticle modified asphalt binder at low and intermediate temperature range

There is a paucity of knowledge regarding the effect of nanoparticles on the performance of asphalt binder against fatigue and low-temperature cracking. In this research, asphalt binders were modified using SiO₂, TiO₂, and CaCO₃ nanoparticles, and rheological and thermal properties of the modified binders were investigated. Differential scanning calorimetry was used to determine glass transition temperature, and rheological properties at low and intermediate temperatures were determined using bending beam and dynamic shear rheometers, respectively. The results suggested that the addition of these nanoparticles increases glass transition temperature and the low-temperature stiffness of asphalt binder. Furthermore, increase in complex shear modulus and decrease in phase angle values were observed at intermediate temperatures. It can be concluded that inferior performance at low and intermediate temperature is expected by the addition of nanoparticles to asphalt binder.     

纳米CaCO3改性沥青与SBS改性沥青综合比较研究

选择纳米CaCO3和SBS为改性剂,研究其对基质沥青的改性作用。针对改性剂的特性确定了相应的制备工艺。通过针入度、软化点、延度、布氏粘度扣动态剪切流变试验及混合料试验评价了改性沥青的路用性能。结果表明纳米CaCO3改性沥青路用性能得到了显著改善。最后对三种典型掺量的改性沥青性价比进行了对比分析,认为纳米CaCO3改性沥青在低等级路面使用中具有较高的性价比。     

The addition effects of macro and nano clay on the performance of asphalt binder

The study was carried out to explore the addition effect of macro and organically modified nanoclay on the physical and mechanical properties of asphalt binders. Both macroclay and modified nanoclay were blended in an asphalt binder in various percentages (starting from 2% to 8%). The blended asphalt binders were characterized using kinematic viscosity (C.st), softening point (°C), and penetration and compared with anunmodified binder. The tensile strength of the asphalt binders was also tested as a function of clay types and content%. The results of the study indicated an increase in softening point; kinematics viscosity and decrease in binder penetration. The tensile strength of modified clay binders was enhanced at all percentages by a comparison with both macroclay and unmodified binders. The best improvements in the modified binders were obtained with 6% nanoclay.     

Laboratory evaluation of the effect of SBS and Lucobite on performance properties of bitumen

In this research, the effects of two additives namely SBS (3, 5%) and Lucobite (3, 5%) on the performance properties of binder were evaluated. The binder fatigue and rutting performance was evaluated through linear amplitude sweep (LAS) and multiple stress creep and recovery (MSCR) test, respectively. Results indicated that 3% SBS modified binder has the highest percent recovery value and the lowest Jnr value, but had the highest sensitivity to a sudden increase in the stress level inside the asphalt mixture. The LAS test results demonstrated that the fatigue behavior of asphalt binders modified with 3% Lucobite, is the highest one.     

The properties of nanosilica-modified asphalt cement

This study aimed to investigate some engineering properties of asphalt cement modified with different percentages of nanosilica. 60/70 Penetration grade asphalt cement was modified with different percentages of nanosilica (i.e. 1, 3, and 5 wt%) and their properties were evaluated. After evaluating the modified binder using scanning electron microscopy, the penetration grade, softening point, and ductility of the modified binder were measured. Using the penetration grade and softening point, the penetration index of the binders was determined. The results showed that the binder stiffness increases and the ductility and temperature sensitivity decreases with increasing nanosilica content.     

RTFOT与TFOT对沥青胶结料热老化程度的影响

通过分析老化沥青残留物的质量变化，针久度，粘度，车辙因子和低温蠕变性能，比较RTFOT和TFOT条件下沥青胶结料热老化程度的差异，结果表明：TFOT残留物在常温和高温下的粘度及车辙因子平均水平均低于RTFOT残留物，但低温性能呈现出不同的行为，影响程序取决于沥青品种，当对沥青进行PG分级时，若沥青性能指标接近临界值时，不能忽 视两种老化条件引起的差异，否则容易出现误判。     

Short- and long-term rheological and chemical characteristics of nanomodified asphalt binder

Due to the special characteristics of nanoparticles, pavement engineers have used nanoparticles as an additive in asphalt pavement to improve pavement performance. This study focuses on characterizing modified asphalt performance using nanoclay particles compared to the unmodified asphalt binder. For this evaluation, 3% of nanoclay particles were added to a neat binder to prepare the nanomodified binder. Then, the modified and unmodified binders underwent a short- and long-term aging process using the Rolling Thin Film Oven (RTFO) and two cycles of Pressure Aging Vessel (PAV). Finally, the Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), and Fourier-Transform Infrared Spectroscopy - Attenuated Total Reflection (FTIR-ATR) tests were carried out in each aging step to assess and monitor the rutting, fatigue, low-temperature performance, durability, and chemical changes of binders during the aging process. The results of this study proved the enhanced properties and performances of the nanomodified binder compared to the unmodified binder. These results can pave the path with the use of nanomodified binders in the recycling of aged pavement and construction of roads that experience poor weather conditions and high traffic loads.     

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.     

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.