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In this work, the effect that filler has on the aging of bitumen was analyzed but with the filler being incorporated by volume, not by weight. The Universal de Caracterización de Ligantes method was used as the process of accelerated aging, and a new direct tensile test was used to determine the toughness of the aged mixture and, thus, to assess the effect the filler has. All tests performed for this paper have shown the protective effect of the fillers used. The new direct tensile test developed by the Road Research Laboratory of the Technical University of Catalonia allows observation of how an increase in filler produces an increase in the breaking load and a decrease in the maximum deformation: the hydrated lime tends to stiffen the mixture less and make it less brittle than does calcium carbonate. To minimize the effect of aging on bitumen, the filler content proposed must be 20% or 30% less than the content recommended in conditions where there is no aging, so that when the mixture ages, the mastic is able to build up the maximum energy possible.The processes that a binder undergoes when aging, which cause its progressive hardening, may damage its aggregate-bitumen adhesive qualities and, thus, the cohesion of the mixture.The addition of filler to the mixture can improve adhesion and cohesion substantially (filler is a fine material-it passes a 0.063-mm sieve-derived from aggregate or other similar granular material). The bitumen-filler system (mastic), which is thicker and tougher than bitumen alone, improves the adhesive qualities and, in providing a covering film of greater thickness, also can slow down the aging processes. The effects of the addition of filler are directly related to their characteristics and the degree of concentration of the filler in the bitumen-filler system.The advantages that filler offers for the durability of the bituminous mixtures in the case of water action are due, in principle, to its physical characteristics, which reduce the porosity of the granular structure and thereby make access by water and air difficult. Moreover, the chemical nature of filler may mean greater affinity with the asphalt binder, which can improve resistance to the displacement that water causes the bitumen.Using immersion tests, Craus et al. assessed the influence that the type of filler had on the durability of the bituminous mixtures (1). They reviewed the usual criteria of mixture design, with analyses that simulated short periods of exposure to the environment (for example, for the case under study, the residual Marshall stability and the resistance of immersion-compression); they noted that mixtures that pass these tests usually fail completely in service. With the obtained results, they were able to modify the existing criteria for the classification of fillers, which had been based only on basic properties without consideration of the durability factor. From this work, the authors have continued studying the effect of the characteristics of fillers on the durability of the mixtures (2).Diverse...

In this work the effect filler has on the aging of bitumen is analyzed, but incorporating the filler in volume and not in weight. The UCL method is used as the process of accelerated aging and new direct tensile test is used to determine the toughness of the aged mixture and, thus, to assess the effect the filler has.All the tests performed for this paper have shown the protective effect of the fillers used. The new direct tensile test developed by the Road Research Laboratory of the Technical University of Catalonia, allows to observe how an increase of filler produces the increase of the breaking load and the decrease of the maximum deformation, observing that the hydrated lime tends to stiffen the mixture less and make it less brittle than calcium carbonate.In order to minimize the effect of aging on bitumen, the filler content proposed must be 20 or 30% less than the content recommended in conditions when there is no aging, so that when the mixture ages the mastic is able to build up the maximum energy possible.

The aim of this paper is to explain phenomena associated with bitumen aging and establish design patterns that contribute to optimizing the aging resistance of bituminous mixes based on the rational addition of calcareous fillers (hydrated lime and limestone filler).The potential benefits of using fillers to improve aging resistance are well-known. However, concepts related to the biphasic filler-bitumen system affecting some of the main characteristics of mixes are not always considered.In this paper, a new study procedure, "Universal de Caracterización de Ligantes" (UCL®), a method for characterizing both conventional and polymer-modified binders developed at the Technical University of Catalonia, has been applied. In addition, rheological tests have been performed with the dynamic shear rheometer and non-routine procedures such as macromolecular analysis (e.g. gel-permeation chromatography and infrared spectroscopy). These techniques have provided greater insight into the causes and effects of aging based on the changes undergone by the bituminous binder.The obtained results show the advantages of incorporating calcareous fillers into bituminous mixes provided that filler content does not exceed a "critical concentration" determined by the type of filler and binder to be used. Moreover, some variations on the concept of critical concentration of filler in bituminous mixes have been found, notably those resulting from the degree of mix aging and use of polymer-modified bitumens.Bianchetto, Miró, Pérez-Jiménez, Martínez 3 INTRODUCTION Aging is one of the reasons for the failure of bituminous wearing courses. The consequences of this process are a decrease in the level of comfort and safety and an increase in pavement maintenance and rehabilitation activities, which results in higher costs.Most of the research to date has focused on binders in isolation. The "aging" factor has been assessed by accelerated simulation of some of the mechanisms affecting this deterioration process.Petersen (1), Khandal and Chakraborty (2) and other researchers observed that the primary causes of aging are light fraction volatilization and oxidation resulting from a "dual mechanism" by which oxygen is combined with highly reactive elements of the hydrocarbon. This gives rise to the appearance of cyclic-aromatic compounds. A slow oxidation process of benzylic carbons, whose main final product is ketones (3), is then initiated.Classical characterization methods do not allow material behavior to be accurately predicted during service time since void content, aggregate-binder interaction and the effect of mineral filler and other additives dramatically change the characteristics of bitumen in the final mix (4). The irruption of polymer-modified binders into the road industry brought into question the validity of these processes.The past few years have witnessed the emergence of new techniques for simulating transformation processes undergone by bitumen in bituminous mixes as it ages and the way it acts. Such methodologies consid...

In the rehabilitation of flexible pavements with asphalt layers, it is necessary to apply a bituminous tack coat with a pre-established dosage, which usually does not take into account the degree of texture generated if a milling operation is previously performed since this increases the surface at the interface. On the other hand, when milling, grooves are obtained that could lead to the runoff of bitumen emulsion with excessive deposition in their valleys due to dosages greater than those needed. This work analyses the above mentioned and achieves a compromise solution, with its corresponding method of application, based on the mechanical behaviour obtained with different degrees of texture and validated for typical materials used in Argentina.