Rheological evaluation of asphalt binder modified by amorphous poly alpha olefin (APAO)

High production costs and poor storage stability have become important constraints in the manufacture of modified asphalt binder. To simplify the production process and reduce the production cost, amorphous poly alpha olefin (APAO) and polyphosphoric acid (PPA) were applied to prepare highly stable modified asphalt binder. The influence of APAO/PPA on the temperature sensitivity, rheological property, storage stability, compatibility and microstructure of neat binder were studied by rotational viscosity (RV), dynamic shear rheometer (DSR), bending beam rheometer (BBR) and Fourier transform infrared (FTIR) spectroscopy. The results show that the incorporation of APAO/PPA reduced the temperature sensitivity of neat binder. The combined effect of APAO/PPA contributed to the improvement in deformation resistance, which was evidenced by the increase in failure temperature and percent recovery. However, the compound modification of APAO/PPA decreased the binder’s low-temperature performance. APAO strengthened the fatigue resistance of the binder, while PPA reduced the anti-fatigue performance. Composite modified asphalt binder with superior storage stability could be prepared, which was confirmed by the desired Cole–Cole plots and fluorescence imaging. Furthermore, chemical and physical reactions occurred during the APAO/PPA modification process. Overall, 2 wt.% (weight percentage) APAO and 1.5 wt.% PPA are recommended for the production of modified asphalt binder with remarkable rheological performance and storage stability.

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The interfacial effect of mineral filler to asphalt binder and its influence on asphalt aging behavior

Materials and Structures ◽

10.1617/s11527-020-01605-6 ◽

2021 ◽

Vol 54 (1) ◽

Author(s):

Fan Li ◽

Yuyou Yang

Keyword(s):

Asphalt Binder ◽

Interfacial Effect ◽

Mineral Filler ◽

Aging Behavior

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A Hybrid Model to Predict the Gyratory Compaction of Hot Mixed Asphalt

10.31224/osf.io/b7gk6 ◽

2019 ◽

Author(s):

Teng Man

Keyword(s):

Hybrid Model ◽

Asphalt Binder ◽

Asphalt Mixture ◽

Aggregate Size ◽

Asphalt Mixtures ◽

Compaction Process ◽

Particle Rearrangement ◽

Compaction Behavior ◽

Grain Size Distributions ◽

Gyratory Compaction

The compaction of asphalt mixture is crucial to the mechanical properties and the maintenance of the pavement. However, the mix design, which based on the compaction properties, remains largely on empirical data. We found difficulties to relate the aggregate size distribution and the asphalt binder properties to the compaction behavior in both the field and laboratory compaction of asphalt mixtures. In this paper, we would like to propose a simple hybrid model to predict the compaction of asphalt mixtures. In this model, we divided the compaction process into two mechanisms: (i) visco-plastic deformation of an ordered thickly-coated granular assembly, and (ii) the transition from an ordered system to a disordered system due to particle rearrangement. This model could take into account both the viscous properties of the asphalt binder and grain size distributions of the aggregates. Additionally, we suggest to use the discrete element method to understand the particle rearrangement during the compaction process. This model is calibrated based on the SuperPave gyratory compaction tests in the pavement lab. In the end, we compared the model results to experimental data to show that this model prediction had a good agreement with the experiments, thus, had great potentials to be implemented to improve the design of asphalt mixtures.

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Material Properties and Environmental Benefits of Hot-Mix Asphalt Mixes Including Local Crumb Rubber Obtained from Scrap Tires

Environments ◽

10.3390/environments8060047 ◽

2021 ◽

Vol 8 (6) ◽

pp. 47

Author(s):

Lim Min Khiong ◽

Md. Safiuddin ◽

Mohammad Abdul Mannan ◽

Resdiansyah

Keyword(s):

Asphalt Binder ◽

Crumb Rubber ◽

Environmental Benefits ◽

Asphalt Binders ◽

Rubber Content ◽

Scrap Tires ◽

Asphalt Mixes ◽

Temperature Resistance ◽

Modified Asphalt ◽

Marshall Stability

This paper presents the results of a laboratory-based experimental investigation on the properties of asphalt binder and hot-mix asphalt (HMA) mixes modified by locally available crumb rubber, which was used as a partial replacement of asphalt by weight. In this study, fine crumb rubber with a particle size in the range of 0.3–0.6 mm, obtained from scrap tires, was added to the asphalt binder through the wet process. Crumb rubber contents of 5%, 10%, 15%, and 19% by weight of asphalt were added to the virgin binder in order to prepare the modified asphalt binder samples, while the unmodified asphalt binder was used as the control sample. The crumb rubber modified binder samples were examined for measuring viscosity indirectly using the penetration test, and temperature resistance using the softening point test. Later, both the modified and unmodified asphalt binders were used to produce HMA mixes. Two categories of HMA mix commonly used in Malaysia—namely, AC 14 (dense-graded) and SMA 14 (gap-graded)—were produced using the modified asphalt binders containing 5%, 10%, 15%, and 19% crumb rubber. Two AC 14 and SMA 14 control mixes were also produced, incorporating the unmodified asphalt binder (0% crumb rubber). All of the AC 14 and SMA 14 asphalt mixes were examined in order to determine their volumetric properties, such as bulk density, voids in total mix (VTM), voids in mineral aggregate (VMA), and voids filled with asphalt (VFA). In addition, the Marshall stability, Marshall flow, and stiffness of all of the AC 14 and SMA 14 mixes were determined. Test results indicated that the modified asphalt binders possessed higher viscosity and temperature resistance than the unmodified asphalt binder. The viscosity and temperature resistance of the asphalt binders increased with the increase in their crumb rubber content. The increased crumb rubber content also led to improvements in the volumetric properties (bulk density, VTM, VMA, and VFA) of the AC 14 and SMA 14 mixes. In addition, the performance characteristics of the AC 14 and SMA 14 mixes—such as Marshall stability, Marshall flow, and stiffness—increased with the increase in crumb rubber content. However, the AC 14 mixes performed much better than the SMA 14 mixes. The overall research findings suggest that crumb rubber can be used to produce durable and sustainable HMA mixes, with manifold environmental benefits, for use in flexible pavements carrying the heavy traffic load of highways.

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Optimization the Physical Properties of Waste Denim Fiber Modified Bio-asphalt Binder Using Response Surface Methodology

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1144/1/012075 ◽

2021 ◽

Vol 1144 (1) ◽

pp. 012075

Author(s):

Abdulnaser Al-Sabaeei ◽

Madzlan Napiah ◽

Muslich Sutanto ◽

Wesam Alaloul ◽

Nur Izzi Md Yusoff ◽

...

Keyword(s):

Response Surface Methodology ◽

Physical Properties ◽

Response Surface ◽

Asphalt Binder

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Greener Solution to Waste Corn Stalks and Shortage of Asphalt Resource: Hydrochar Produced by Hydrothermal Carbonization as a Novel Performance Enhancer for Asphalt Binder

Materials ◽

10.3390/ma14061427 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1427

Author(s):

Xiaoming Wu ◽

Chichun Hu

Keyword(s):

High Temperature ◽

Reaction Temperature ◽

Storage Stability ◽

Asphalt Binder ◽

Aging Effect ◽

Experimental Tests ◽

Hydrothermal Carbonization ◽

Modified Asphalt ◽

Direct Combustion ◽

Aging Property

Utilization of waste corn stalks (CS) has seized extensive attention due to high annual output and hazardous impact of piling aside or direct combustion on environment. However, previously there has been a lot of emphasis on improvement of its energy efficiency as solid fuel while limited investigations are available which explore the possibility of applying corn stalks as performance enhancer in asphalt binder. The purpose of this study is to examine the potential of employing hydrochar as modifiers in asphalt binder by a series of experimental tests. In this study, two hydrochar were produced from corn stalks by a novel process called hydrothermal carbonization at a different reaction temperature. The two hydrochar and their responding hydrochar-modified asphalt (HCMA) were tested by chemical and rheological tests. Chemical analysis detected the interaction between hydrochar and binder factions, resulting in poor compatibility but satisfying anti-aging property. Even though hydrochar increased the viscosity of bitumen, implying worse workability, and caused poor storage stability, ameliorated performance of asphalt binder at high temperature by incorporating hydrochar was verified by various criteria such as higher performance grade (PG) failure temperature and lower non-recoverable creep compliance (Jnr). Moreover, higher reaction temperature makes hydrochar’s particles smaller and more homogeneous, which results in slightly lower enhanced high temperature performance, more satisfying workability, better storage stability, and greater anti-aging effect of hydrochar-modified asphalt. Eventually, this study provided a promising win-win solution to environment problems concerning corn stalk treatment and shortage of asphalt binder. Further exploration of methods to improve HCMA’s storage stability, real-scale corroboration on trial section and life cycle assessment of asphalt pavement containing hydrochar modifiers will be followed in the future.

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Recent advances in characterizing the “bee” structures and asphaltene particles in asphalt binders

International Journal of Pavement Research and Technology ◽

10.1007/s42947-020-6008-3 ◽

2020 ◽

Vol 13 (6) ◽

pp. 697-706

Author(s):

Yuhong Wang ◽

Kecheng Zhao ◽

Fangjin Li ◽

Qi Gao ◽

King Wai Chiu Lai

Keyword(s):

Near Field ◽

Asphalt Binder ◽

Optical Microscope ◽

Asphalt Binders ◽

Zero Shear Viscosity ◽

Surface Features ◽

Asphaltene Content ◽

Scanning Transmission ◽

Before And After ◽

Binder Aging

AbstractThe microscopic surface features of asphalt binders are extensively reported in existing literature, but relatively fewer studies are performed on the morphology of asphaltene microstructures and cross-examination between the surface features and asphaltenes. This paper reports the findings of investigating six types of asphalt binders at the nanoscale, assisted with atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). The surface features of the asphalt binders were examined by using AFM before and after being repetitively peeled by a tape. Variations in infrared (IR) absorbance at the wavenumber around 1700 cm−1, which corresponds to ketones, were examined by using an infrared s-SNOM instrument (scattering-type scanning near-field optical microscope). Thin films of asphalt binders were examined by using STEM, and separate asphaltene particles were cross-examined by using both STEM and AFM. In addition, connections between the microstructures and binder’s physicochemical properties were evaluated. The use of both microscopy techniques provide comprehensive and complementary information on the microscopic nature of asphalt binders. It was found that the dynamic viscosities of asphalt binders are predominantly determined by the zero shear viscosity of the corresponding maltenes and asphaltene content. Limited samples also suggest that the unique bee structures are likely related to the growth of asphaltene content during asphalt binder aging process, but more asphalt binders from different crude sources are needed to verify this finding.

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