State of the art of tribological tests for bituminous binders

Canestrari, Francesco; Ingrassia, Lorenzo Paolo; Ferrotti, Gilda; Lu, Xionggang

doi:10.1016/j.conbuildmat.2017.09.121

Cited by 23 publications

(19 citation statements)

References 37 publications

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“…This is not only true for the mixtures after placing but also during construction, since workability and compactability of asphalt mixtures are closely influenced by type and gradation of aggregates, viscosity of binder, and temperature (Bayer, 1994;Leiva & West, 2008). In the meanwhile, some studies claimed that the correlation between compactability and bitumen viscosity is not as evident for warm mix asphalt as the reduction in friction between particles (Canestrari, Ingrassia, Ferrotti, & Lu, 2017;Hanz, Faheem, Mahmoud, & Bahia, 2010). Thus, it appears that the mechanical behaviour of asphalt mixtures at these large displacement situations is very sensitive and variable, and difficult to be adequately assessed or predicted through existing modelling or experimental techniques.…”

Section: Introduction 1backgroundmentioning

confidence: 99%

Experimental and numerical analysis of asphalt flow in a slump test

Chen

Jelagin

Partl

2019

Road Materials and Pavement Design

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The mechanical behaviour of uncompacted asphalt mixtures is still not well understood, threatening directly to the pavement practices such as control of mixture's workability and segregation. This situation may become even worse due to the gradually increasing complexity and advances in paving materials and technologies. This study adopts a slump flow test based on concrete technology and a Discrete Element (DE)-based numerical tool to investigate the mechanical behaviour of uncompacted asphalt mixture from a microstructural point of view, particularly focusing on the bituminous binder effects. The combined experimental and numerical analysis indicates that bitumen distinctly influences the contact interactions within the mixture and thus its macroscopic flow, which can be physically interpreted as a combined effect of lubricated friction and bonding force. Additional case studies demonstrate that the DE model is capable of simulating the flow response of asphalt mixtures under changed particle contact conditions and driven force.

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Section: Introduction 1backgroundmentioning

confidence: 99%

Experimental and numerical analysis of asphalt flow in a slump test

Chen

Jelagin

Partl

2019

Road Materials and Pavement Design

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“…In tribology, the lubrication properties of a material placed between two solids in relative motion is normally described through the Stribeck curve ( Figure 1), which shows the evolution of the coefficient of friction µ as a function of the sliding speed [16,17]. The change in the coefficient of friction values is due to the variation of the thickness of the lubricating film, as shown in Figure 1.…”

Section: Mechanism Of Friction and Lubricationmentioning

confidence: 99%

“…The change in the coefficient of friction values is due to the variation of the thickness of the lubricating film, as shown in Figure 1. The Stribeck curve can be generally divided into four regions, which correspond to different regimes of lubrication [16,17]:…”

Section: Mechanism Of Friction and Lubricationmentioning

confidence: 99%

“…However, in addition to the sliding speed, other important parameters also govern the phenomenon. Since friction is not an intrinsic property of the material but of the overall system, it strongly depends also on the nature, surface roughness and wear of the solids in contact [16,17]. Such factors are extremely crucial mainly when the lubricating film is not thick enough to separate all solid asperities.…”

Section: Mechanism Of Friction and Lubricationmentioning

confidence: 99%

“…Most likely, a different mechanism is responsible for the reduction of compaction efforts. In this regard, a new test method, used for lubricants and based on tribology, has been recently proposed in order to characterize the lubricating behaviour of asphalt binders [15][16][17][18]. To date, this approach has been used mainly to investigate the lubricating properties of warm mix asphalt (WMA) binders, produced with different WMA technologies [17,19,20].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Graphite Nanoplatelets Influence on the Lubrication Properties of Asphalt Binders

et al. 2020

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With the major advance in nanotechnology, there has been an emerging interest in applying nanoscale materials to asphalt pavement materials. Among them, considerable interest has been directed to carbon-based nanomaterials, such as carbon nanotubes (CNTs) and graphite nanoplatelets (GNPs). Recent studies have proven that the addition of small percentages of GNPs could significantly reduce the compaction effort required to densify HMA. Viscosity measurements showed, however, that the addition of GNPs increased the viscosity of the binder. This observation pointed towards the presence of a different mechanism responsible for the reduction of compaction effort. A new test method used for lubricants and based on tribology has been recently proposed in order to characterize the lubricating behaviour of asphalt binders. In this study, the tribological characterization of an asphalt binder modified with GNPs was performed. A novel approach in which aggregate surface microtexture was simulated using rough surfaces of the testing fixtures, shows that indeed, the addition of GNPs lowers the friction coefficient and therefore, enhances the lubrication properties of the binder when mixed with mineral aggregates.

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