Author
Fangjin Li
Bio: Fangjin Li is an academic researcher from Hong Kong Polytechnic University. The author has contributed to research in topics: Asphalt & Asphaltene. The author has an hindex of 3, co-authored 5 publications receiving 28 citations.
Topics: Asphalt, Asphaltene, Chemical property
Papers
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TL;DR: In this article, a new approach is developed to assess rejuvenation effectiveness, using relaxation spectra calculated from the oscillation shear test data of asphalt binders, which enables the assessment of reduction in the proportion of large microstructures in aged asphalt binder.
28 citations
TL;DR: In this paper, asphaltenes in nine types of asphalt that vary in crude oil source and aging states are examined through scanning transmission electron microscopy and atomic force microscopy (AFM).
21 citations
TL;DR: Unexpected rise in saturates was found in asphalt binders aged in pressurised pure oxygen, and Colloidal instability index indicates that some binders are more resistant to oxidative ageing than others, and sulphur appears to play an important role.
Abstract: This study examines the influence of different ageing conditions on the commonly interested chemical properties of asphalt binders, including the oxygenated functional groups and Corbett fractions....
16 citations
TL;DR: In this paper, the surface features of asphalt binders were examined by using atomic force microscopy (AFM) and scanning transmission electron microscopy(STEM), and connections between the microstructures and binder physicochemical properties were evaluated.
Abstract: The 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.
6 citations
13 Dec 2018
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01 Jan 2014
TL;DR: In this paper, 100% recycled hot mix asphalt lab samples were modified with five generic and one proprietary rejuvenators at 12% dose and tested for binder and mixture properties, which ensured excellent rutting resistance while providing longer fatigue life compared to virgin mixtures and most lowered critical cracking temperature.
Abstract: 100% recycled hot mix asphalt lab samples were modified with five generic and one proprietary rejuvenators at 12% dose and tested for binder and mixture properties. Waste Vegetable Oil, Waste Vegetable Grease, Organic Oil, Distilled Tall Oil, and Aromatic Extract reduced the Superpave performance grade (PG) from 94–12 of extracted binder to PG 64-22 while waste engine oil required higher dose. All products ensured excellent rutting resistance while providing longer fatigue life when compared to virgin mixtures and most lowered critical cracking temperature. Rejuvenated samples required more compaction energy compared to virgin and some oils reduced moisture resistance slightly.
214 citations
TL;DR: A review of the literature on the applications of various types of rejuvenators in paving industry and their effects on the properties of the aged binders is presented in this paper, where the techniques for rejuvenating the aged asphalt binders and the mechanism of rejuvenation are also reviewed.
178 citations
TL;DR: In this article, the authors summarized the application of gel permeation chromatography (GPC) in characterizing asphalt materials and made several suggestions for the future application of GPC technology in asphalt material analysis.
43 citations
TL;DR: In this paper, the authors investigated the influence of aging on the bonding property of asphalt binder and explained the reason behind the change of bonding property, where four neat asphalt binders were treated with shortterm aging and long-term aging.
42 citations
TL;DR: In this paper, the authors aim to improve the rheological properties and ductility characteristics of aged asphalt-binder using waste engine oil (WEO) injected into the mixture.
Abstract: The work presented in this paper aims to improve the rheological properties and ductility characteristics of aged (short-term) asphalt-binder using waste engine oil (WEO). The WEO was injected into...
36 citations