Microstructural properties of warm mix asphalt before and after laboratory-simulated long-term ageing

Menapace, Ilaria; Masad, Eyad; Bhasin, Amit; Little, Dallas N.

doi:10.1080/14680629.2015.1029692

Cited by 64 publications

(47 citation statements)

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Section: Introductionmentioning

confidence: 99%

“…An additional advantage of reduced temperature in production is reduction in harmful fume emissions. There are no conclusive results showing whether or not lower production temperatures, which lead to less oxidation during shortterm ageing, also affect long-term ageing of binders and asphalt mixtures (Arega, Bhasin, & De Kesel, 2013;Banerjee, de Fortier Smit, & Prozzi, 2012;Menapace, Masad, Bhasin, & Little, 2015).The question of how the chemical composition, the mechanical behaviour and microstructure of bitumen are linked has been of interest to researchers for decades (Eberhardsteiner et al, 2015a). An increasing number of studies related to this question have been observed in recent years (Allen, Little, Bhasin, & Glover, 2014; Eberhardsteiner et al, 2015b;Handle et al, 2016;Poulikakos et al, 2014).…”

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confidence: 99%

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Effect of short-term ageing temperature on bitumen properties

Hofko

Falchetto

Grenfell

et al. 2017

Road Materials and Pavement Design

106

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Properties of asphalt mixtures after ageing are fundamental parameters in determining longterm performance (e.g. durability) of these materials. With increasing popularity of reduced temperature mixtures, such as warm-mix asphalt, WMA, the question remains how a reduction in short-term ageing affects the properties after long-term ageing of bituminous materials. This paper aims to improve our understanding of the effect of asphalt manufacturing temperature on ageing and the resulting mechanical properties of bituminous binder by studying the effect of short-and long-term ageing of different bitumen samples as a function of short-term ageing temperatures. For this purpose, round robin experiments were conducted within the RILEM technical committee (TC) 252 chemo-mechanical characterisation of bituminous materials by 10 laboratories from 5 countries using four binders of the same grade (70/100 pen) from different crude sources. The short-term ageing was carried out using the standard procedure for rolling thin film oven test (RTFOT), but varying the temperatures. Long-term ageing was carried out using the standard procedure for pressure aging vessel (PAV) in addition to RTFOT. For the mechanical characterisation, rheological data were determined by using the dynamic shear rheometer (DSR) and conventional tests, with needle penetration and softening point using the ring and ball method. The results show that although different short-term ageing temperatures showed a significant difference in the mechanical properties of the binders, these differences vanished after long-term ageing with PAV.Keywords: bitumen; DSR; long-term ageing; short-term ageing; asphalt; RTFOT; PAV IntroductionAs an organic material, bitumen undergoes changes in its mechanical characteristics, chemical composition and microstructure due to environmental effects over its lifetime (Glotova, Gorshkov, Kats, Shapiro, & Yureva, 1980;Lee, Tia, Ruth, & Page, 1997;Mills-Beale et al., 2012;Yao, Dai, & You, 2015). Loss of volatile components at elevated temperatures and oxidation are two main factors for these changes. In terms of mechanical properties, bitumen tends to become stiffer, more elastic and brittle over time. Road Materials and Pavement Design109 SARA (saturates, aromatics, resins and asphaltenes) fractions can be observed with an increasing amount of asphaltenes and decreasing amount of aromatics over time Lu & Isacsson, 2002). These changes are generally summarised under the term "ageing". Bitumen ageing can be split up into short-term and long-term ageing. In the case of hot mix asphalt, short-term ageing occurs during asphalt mix production, transport and compaction at the construction site, all of which happens within hours. It is characterised by relatively high temperatures ( > 130°C) and thus, high oxidation rates. Long-term ageing occurs in asphalt pavements in the field as a result of exposure to traffic and climatic conditions during its service life. Compared to short-term ageing, long-term ageing is a slow oxidation process tha...

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Effect of short-term ageing temperature on bitumen properties

Hofko

Falchetto

Grenfell

et al. 2017

Road Materials and Pavement Design

106

View full text Add to dashboard Cite

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“…The cumulative dissipated energy density was obtained as the sum of all dissipated energy densities, as shown in equation [3].…”

Section: Experimental Studymentioning

confidence: 99%

“…This phenomenon causes, firstly, bitumen hardening which affects the rheological and mechanical properties of the mixture (3). It causes a change in their behaviour which goes from ductile to brittle.…”

Section: Introductionmentioning

confidence: 99%

Ageing and temperature effect on the fatigue performance of bituminous mixtures

López-Montero

Recasens

2017

Mater. construcc.

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ABSTRACT:The ageing of asphalt mixes, together with their exposure to low temperatures, causes a progressive increase of cracking. In this paper, the effect of ageing and temperature on the fatigue of asphalt concretes made with two types of binders, conventional (50/70) and polymer modified bitumen (PMB), is studied. For this purpose, specimens previously subjected to an accelerated laboratory ageing process were tested by a strain sweep test at different temperatures (-5ºC, 5ºC and 20°C). Results were compared with the obtained from the unaged specimens showing the relative importance of ageing, temperature and type of bitumen on the parameters that determine the fatigue life of the mixture. The mixtures behaviour becomes more brittle with ageing and the decrease of temperature. However, ageing hardly has an effect on fatigue at lower temperatures. In general, mixtures made with polymer modified bitumen have a better fatigue performance to ageing and temperature. RESUMEN: Efecto del envejecimiento y de la temperatura en el comportamiento a fatiga de las mezclas bituminosas.el envejecimiento de las mezclas, unido a su exposición a bajas temperaturas, provoca un progresivo aumento de su fisuración. En este trabajo, se estudia el efecto del envejecimiento y la temperatura en la fatiga de una mezcla semidensa fabricada con dos tipos de ligantes, 50/70 y PMB 45/80-65. Para ello, probetas previamente sometidas a envejecimiento acelerado en laboratorio fueron ensayadas mediante un ensayo de barrido de deformaciones, a diferentes temperaturas (-5, 5 y 20ºC). Los resultados fueron comparados con los obtenidos en mezclas no envejecidas mostrando la importancia del envejecimiento, temperatura y ligante sobre los parámetros que condicionan la vida a fatiga de la mezcla. El comportamiento de las mezclas es más frágil debido al envejecimiento y la disminución de la temperatura. Sin embargo, el envejecimiento apenas influye en la fatiga a temperaturas bajas. En general, las mezclas con betún modificado muestran mejor respuesta a fatiga frente a envejecimiento y temperatura.

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“…Menapace et al . () hypothesized a development of bee‐like structures through dendritic growth. Fractal structures were visible in samples with higher stiffness and therefore low molecular mobility.…”

Section: Introductionmentioning

confidence: 99%

Effect of treatment temperature on the microstructure of asphalt binders: insights on the development of dispersed domains

Menapace

Masad

Bhasin

2015

Journal of Microscopy

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This paper offers important insights on the development of the microstructure in asphalt binders as a function of the treatment temperature. Different treatment temperatures are useful to understand how dispersed domains form when different driving energies for the mobility of molecular species are provided. Small and flat dispersed domains, with average diameter between 0.02 and 0.70 μm, were detected on the surface of two binders at room temperature, and these domains were observed to grow with an increase in treatment temperature (up to over 2 μm). Bee-like structures started to appear after treatment at or above 100°C. Moreover, the effect of the binder thickness on its microstructure at room temperature and at higher treatment temperatures was investigated and is discussed in this paper. At room temperature, the average size of the dispersed domains increased as the binder thickness decreased. A hypothesis that conciliates current theories on the origin and development of dispersed domains is proposed. Small dispersed domains (average diameter around 0.02 μm) are present in the bulk of the binder, whereas larger domains and bee-like structures develop on the surface, following heat treatment or mechanical disturbance that reduces the film thickness. Molecular mobility and association are the key factors in the development of binder microstructure.

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Microstructural properties of warm mix asphalt before and after laboratory-simulated long-term ageing

Cited by 64 publications

References 35 publications

Effect of short-term ageing temperature on bitumen properties

Effect of short-term ageing temperature on bitumen properties

Ageing and temperature effect on the fatigue performance of bituminous mixtures

Effect of treatment temperature on the microstructure of asphalt binders: insights on the development of dispersed domains

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