Differences in cracking resistance of asphalt mixtures due to ageing and moisture damage

Construction and Building Materials

Pérez-Jiménez

2018

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Asphalt binder characterization is a complex and difficult task due to its rheological behaviour. Indeed it has been traditionally realized by means of simple tests at an established temperature. An added challenge is that low temperatures, as well as binder aging, lead to significant changes in the viscoelastic behaviour of binders. This study aimed to characterize asphalt binders, not through the traditional procedures, but through the ductility and tenacity that they provide to a mixture, being these two properties directly related to the cracking response of the binder. To this end, a new approach for asphalt binder characterization was proposed based on the application of the Fénix test on a standard mixture with a defined aggregate gradation and composition, without fines or filler, manufactured with different types of binders and tested at different temperatures, as well as subjected to accelerated aging in laboratory. The obtained results showed the thermal susceptibility of binders, which evidence the need to characterize binder performance at different temperatures to obtain a reliable cracking response. In addition, binder aging results in a more brittle cracking fracture, being the aging effects more pronounced in high penetration binders.

Section: Introductionmentioning

confidence: 99%

New approach to characterize cracking resistance of asphalt binders

Garcia-Gil

Construction and Building Materials

Pérez-Jiménez

2018

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“…This process produces changes in the physical and/or chemical properties of the binder of asphalt mixtures. These changes are manifested in an increase in stiffness and brittleness [6]. In addition, temperature can play a very important role in the effect of aging on the mechanical response of the bitumen that forms asphalt mixtures [7], it being advisable to study their combined effect on the fatigue of mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…EBADE test configuration (units in cm)[6].Maximum stress and strain in each cycle, σ max and , can be obtained from the EBADE test. For each cycle, the complex modulus, |E*|, is obtained from equation…”

mentioning

confidence: 99%

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Obtaining the fatigue laws of bituminous mixtures from a strain sweep test: Effect of temperature and aging

López-Montero

International Journal of Fatigue

Pérez-Jiménez

2017

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Fatigue is associated with the deterioration caused by applying repeated loads, and is affected by temperature or aging. Generally, time sweep tests are used to simulate fatigue, in order to obtain the fatigue laws. However, this requires too much time, often preventing its use. A method to estimate the fatigue laws from a strain sweep test is presented. The test was performed on a semi-dense mixture with different types of binder (unconditioned or aged) tested at different temperatures. This test is able to estimate fatigue laws more quickly, allowing the effect of different factors on the mixtures' fatigue life to be studied.

“…Whereas mixtures broke faster (for a lower number of cycles) and more abruptly (less steps) when they were aged, showing a more brittle behaviour (21).…”

Section: Complex Modulus and Energy Evolution With The Number Of Cyclesmentioning

confidence: 99%

Ageing and temperature effect on the fatigue performance of bituminous mixtures

López-Montero

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.