Method to determine the dosage of bituminous tack coat in function of the texture of milled asphalt layers to be overlaid

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Pavement Engineering on 2019, available online at: http://www.tandfonline.com/10.1080/10298436.2019.1576875In 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.This work was supported by Argentine Ministry of Education [grant number IFI4708TC].Peer ReviewedPostprint (author's final draft

Effect of mixing time and temperature on cracking resistance of bituminous mixtures containing reclaimed asphalt pavement material

The use of reclaimed asphalt pavement (RAP) in bituminous mixtures is considerably increasing due to the environmental and economic benefits of recycled materials. However, stiffer mixes, usually resulting from RAP addition, have raised concern about long-term properties of the pavement; a mechanical characterization of these mixes is thus needed. In this study, the effect of mixing condition on bituminous mixtures containing RAP was evaluated. Volumetric and mechanical properties were analyzed. An experimental program, with the aim of measuring stiffness modulus, water sensitivity, and cracking resistance, was conducted. Cracking resistance was evaluated according to the Fénix test because it has proved to be a convenient and effective method for characterizing cracking behavior of bituminous mixtures at different temperatures. Mixtures containing 20 or 40% of RAP material were tested; virgin aggregates and RAP mixing temperatures as well as mixing time were varied and comparisons with a reference mix were conducted to characterize fracture energy and mechanical performance.Peer ReviewedPostprint (author's final draft

Estimating the fatigue law of asphalt mixtures using a strain sweep test (EBADE test)

Fatigue characterization of asphalt mixtures is a very important issue. However, existing techniques to that end are expensive and time consuming. For that reason the asphalt technicians have been studying several different methods to reduce the testing time needed. Such is the case of the Visco-Elastic Continuum Damage models. In that regard, this paper presents the efforts carried out by the Road Research Laboratory at the UPC-BarcelonaTech to reduce that testing time, by implementing a strain sweep test and approximating the fatigue law of the material from the data obtained. The EBADE test was applied to four mixtures for which the conventional fatigue laws were obtained using time sweep tests. The data collected was used to fit a fatigue model based on two strain values that can be directly computed from the EBADE test, namely Failure strain and No Damage strain. A good correlation was found between the model proposed and the experimental data.Postprint (published version

Evaluación del impacto de los vehículos pesados de transporte de mercancías tipo T2S3 al pasar de 40 a 44 t de M.M.A.

Se ha determinado el efecto del aumento de carga al pasar de 40 a 44t en los vehículos pesados tipos T2S3 y T3S3, sobre todas los firmes de carreteras definidos por la Norma 6.1 IC Secciones de firme, Orden Ministerio de Fomento 3460/2003.Postprint (published version

Effect of the use of Marpol waste as a partial replacement of the binder for the manufacture of more sustainable bituminous mixtures

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Pavement Engineering on 2022, available online at: http://www.tandfonline.com/10.1080/10298436.2022.2046275Society must move towards an economy in which sustainability is its main driving force. A sustainable solution to avoid sending waste to landfill, the consumption of raw materials and, therefore, the depletion of natural resources, is the reuse or recycling of waste. Here, pavement engineering has great potential, as waste can be used for the manufacture of bituminous mixes. In particular, one of these residues is Marpol, which is generated during shipping, maintenance and cleaning operations, including wastewater and waste other than cargo waste. There are few studies on the analysis of its use in mixtures. Thus, in this work, the effect of partially replacing the binder of bituminous mixtures for another obtained from the treatment of Marpol oily waste was studied in order to contribute to environmental sustainability and circular economy. For this, water sensitivity, deformation and cracking resistance were analysed of two asphalt mixtures whose binder was partially replaced by Marpol binder. Furthermore, the binder ageing resistance was studied. The results obtained from the laboratory, plant and test section mixture were very close to those obtained for the reference. These results have demonstrated the feasibility of partially replacing the conventional binder by one obtained from Marpol waste.This research was funded by the Centre for Industrial Technological Development (CDTI) of the Spanish Ministry of Economy and Competitiveness within the framework of the project “Nuevo ligante bituminoso para firmes de carreteras a partir de técnicas de recuperación de residuos oleosos derivados del Marpol” (IDI-20180889).Peer ReviewedPostprint (author's final draft

Assessment of the adhesive capacity of asphalt binders in the aggregate-binder bonds by means of new methodology

The main goal of this study is to present a new methodology to characterize the adhesive capacity (cohesion and adhesion capacity) of asphalt binders by means of new mechanical parameters. This methodology is based on the Fenix test, a test recently developed in Spain. This method assesses the cracking resistance of the asphalt mixtures, and it has been adapted to characterize the bonding power of asphalt binders. The main parameters achieved with this procedure are related to the energy dissipated during the breaking between the asphalt binder and the aggregate, when these materials are subjected to tensile stress; essential parameters related to the adhesive capacity of asphalt binders. The results of an experimental stage are presented in this research, in which the proposed methodology has been applied to analyse the behaviour of the binder in the aggregate-binder matrix according to temperature variation and the effect of water and ageing; taking into account aggregates of the same origin and with a different shape pattern. The results show that the parameters achieved from this new methodology allows characterizing the adhesive capacity of asphalt binders in the different conditions assessed.Postprint (published version

Evaluation of the effect of heat-adhesive emulsions for tack coats with shear test from the road research laboratory of Barcelona

The use of conventional emulsions for tack coats can cause problems as they frequently stick to the tires of construction vehicles. Consequently the bond between the asphalt layers is inadequate. The importance of tack coats in the performance of the pavement means that bituminous emulsions are constantly being improved. Recently, new types of emulsions have been developed from very low penetration bitumen that contains no flux. They are known as “heat-adhesive” emulsions and they are resistant to construction vehicles. The purpose of this study is to analyze the effect of different heat-adhesive emulsions and to verify their performance in service, in comparison with the response of a conventional emulsion. For this reason a new shear test –the LCB test- has been developed in the Road Research Laboratory of the Technical University of Catalonia. This test is carried out at different temperatures, both on laboratory specimens and on cores extracted from recently constructed pavements, where the same emulsions and dosages have been used. The application of the LCB test has shown that the performance of the different heat-adhesive emulsions mainly depends on the characteristics of the base bitumen and the kind of modifier used. At low temperatures, heat-adhesive emulsions reach, in general terms, lower shear resistances than conventional emulsions; however, at intermediate temperatures there are heatadhesives emulsions with both higher and lower strengths than those of the conventional emulsions.Peer Reviewe

Spanish experience with the application of gyratory compactor and indirect tensile test in design and control of cold recycled asphalt pavement

This paper summarizes the Spanish experience in the design and control of cold in-place recycling (CIR) of asphalt pavements. First, the results obtained in laboratory after the mixture design process are compared with the densities encountered in the field. Second, the application of the Superpave Gyratory Compactor (SGC) for specimen manufacture during the design stage is analyzed by varying the standard conditions of gyration angle and vertical pressure. Finally, a new design method based on the indirect tensile test is proposed.Peer Reviewe

Effect of filler nature and content on the bituminous mastic behaviour under cyclic loads

The role of the filler in asphalt mixtures is particularly important because of its influence on mastic behaviour. The filler improves the resistance properties of bitumen against the action of traffic loads and temperature. However, the filler can also adversely affect bitumen in mastics excessively brittle and stiff due to inappropriate design. For these reasons, it is interesting to investigate the effect of filler type and content on mastic composition. This paper presents results from a strain sweep test applied to bituminous mastics prepared with different filler types and contents at several temperatures. The obtained stiffness modulus and failure strain results provide information to assess the fatigue behaviour of the analysed mastics.Peer ReviewedPostprint (author's final draft

Effect of the recycling process and binder type on bituminous mixtures with 100% reclaimed asphalt pavement

There is a great interest in increasing the amount of recycled material used in asphalt mixes because of the beneficial impact on the environment. This is leading to the development of different recycling procedures, from cold in-situ to hot in-plant recycling. The objective of the study presented in this paper is to evaluate cracking resistance of recycled mixes manufactured by three types of processes, i.e., cold with emulsion, hot with high penetration bitumens and hot with emulsion (half-warm mixture), using 100% of reclaimed asphalt pavement (RAP) at different temperatures. Differences in their workability and ease of use are also analysed by gyratory compaction.Peer ReviewedPostprint (author's final draft