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RILEM TC-279 WMR task group TG 1 studied the performance of waste Polyethylene (PE) in bituminous binders and bituminous mixtures. Several laboratories participated in this study following a common protocol. Locally sources aggregates and bituminous binder and same source of waste PE were utilized. The binder experiments showed that at high temperatures, using MSCR tests, PE modified blends had better resistance to permanent deformation in comparison to the non modified binder. Whereas at intermediate temperatures, using the LAS tests, fatigue performance of the PE blends could withstand more loading cycles under low strains; however, it could sustain less loading cycles under high strains due to the increase in brittleness. Dry process was used for the mixture experiments in order to bypass the stability and inhomogeneity experience that was observed at the binder scale. The PE modified mixtures showed improved workability and increased strength. The higher the PE dosage, the higher the ITS increase with respect to the values measured for the control materials (i.e., without any plastic waste) thanks to the improved cohesion of the plastic modified mastic. The stiffness experiments tended to show an improved performance with a lower time dependence and a higher elasticity when plastic was added. The cyclic compression tests demonstrated a reduced creep rate along with a higher creep modulus thanks to the addition of PE; similar conclusions can be drawn from the experimental findings coming from wheel tracking test. Furthermore, acceptable and often improved moisture resistance was observed for PE modified materials., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Pavement Engineering

The use of Reclaimed Asphalt (RA) into new asphalt mixtures becomes an inevitable step for sustainable infrastructure. Saving natural, non-renewable materials, such as bitumen and aggregates, the asphalt industry is moving forward with more recycling. Although asphalt is a 100% reusable material, high recycling rates are not yet easily achievable due to many limitations, going from technical specifications through RA properties to asphalt plant capabilities. The rate of RA, which may be used within a new asphalt mixture, depends on many aspects: variability, moisture and fines contents, presence of polymers, brittleness of aged binder, etc. The latter is directly linked to the degree of the RA binder ageing. As higher RA content increases the asphalt mixture stiffness, the material becomes more brittle and prone to cracking. The use of recycling additives is taking recycling to the next level by solving these issues. With the growing need of the industry for asphalt recycling agents, many products have appeared on the market with different effects. In this study, three asphalt recycling agents (two industrial and one alternative) were used as rejuvenators. Blends with 50% of rejuvenated RA binder (RAb) and virgin binder were subjected to different ageing levels: short (RTFOT), long (PAV for 20 h) and prolonged (PAV for 60 h). After each ageing level, physical, rheological and chemical properties were evaluated addressing the ageing behaviour of the additives used. Testing results showed that one industrial additive lost almost all its properties after prolonged ageing, whereas the other additives showed comparable results with the second industrial product.

This recommendation is based on the results of an inter-laboratory study organised by the RILEM technical committee TC 264-RAP "Asphalt Pavement Recycling"—Task Group 3 (TG3) focusing on Asphalt Binder for Recycled Asphalt Mixture. The TG3 aimed to evaluate the effect of a specific family of materials known as asphalt recycling agent (ARA) on the aged binder under different configurations. Even though ageing is an irreversible phenomenon, effective ARA must have the capability to improve the flexibility of the bituminous materials and their resistance against cracking susceptibility with no adverse effect on the rutting resistance of pavements containing reclaimed asphalt. A total of 17 participating laboratories analysed the properties of binder blends composed of aged binder from reclaimed asphalt in three different contents (60, 80, 100%), ARA and virgin binder. The physical properties of the blends were thoroughly evaluated through traditional and rheological binder testing. This recommendation proposes to restore the original material properties at low and intermediate temperatures (i.e. cracking resistance) while balancing the high-temperature characteristics (i.e. rutting susceptibility) with durable impact throughout the progression of ageing phenomena. Therefore, useing of the Dynamic Shear Rheometer is foreseen as a more suitable and sustainable means to evaluate binder blends containing an asphalt recycling agent. Compared with conventional testing, the proposed approach requires fewer materials while resulting in a faster experimental procedure with one single test.

In this article the affiliation details for A. Kawakami were incorrectly given as ‘‘Department of Biological Information, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan’’ but should have been ‘‘Pavement Research Team, Public Works Research Institute, 1-6 Minamihara, Tsukuba-shi, Ibaraki-ken 305-8516, Japan’’. The original article has been corrected.

The use of rejuvenators has seen a consistent increase over the years in the asphalt pavement industry. This is due to the need for maximizing the demand for incorporating a higher amount of Reclaimed Asphalt (RA) in the pavement asphalt mixtures. In order to tackle this challenge, the Task Group 3, focusing on asphalt binders and additives, of the RILEM TC RAP conducted an interlaboratory activity to evaluate the effect of aging on blends of virgin and rejuvenated RA binders. A set of conventional tests including penetration value at 25 °C, softening point temperature and rheological measurements by means of Dynamic Shear Rheometer (DSR) were selected to involve a large number of participants. A binder, recovered from field RA, was treated with a bio-based rejuvenator and blended with a virgin binder to simulate recycling at three different percentages 60, 80, and 100%. These blends, as well as the pure virgin binder, were next short and long term aged and tested to evaluate the changes in the corresponding properties. Relatively consistent results were obtained for the entire set of blends. The aging of combined rejuvenated RA and virgin binders was comparable to that experienced for the pure virgin binder. DSR data provided a more precise evolution of the impact of aging on the materials.

Aging is a crucial factor in pavement performance and being able to determine its effect on a mixture is necessary to link its initial properties to the properties over time in order to ensure the intended service life. This is becoming more important now that climate change leads to increased variation in weather conditions, while environmental considerations cause changes in the constituent materials that are used. As a result, past experience is becoming less reliable. In this paper, the USA and European approaches to aging are compared, showing that those contain the same test equipment and almost identical conditions for aging. This allows the exchange of data and experience. The current tests are suitable for binders and give an indication of the sensitivity to aging. For short term aging, Rolling Thin Film Oven Test (RTFOT) conditioning gives a reasonable indication of bitumen aging during asphalt concrete production and construction. This only holds for penetration grade binders during hot mix production and construction. For long term aging, because of the many variables involved, developing a single test method to characterize aging sensitivity seems impossible. However, using more elaborate protocols in existing, practical tests can provide more information and the necessary input for kinetic aging expressions. A pressure aging vessel (PAV) protocol for testing at two temperatures and time intervals, specifically at 90 and 100 degrees Celsius and for 20 and 40 hours, respectively, is suggested. Using the same conditioning in characterizing materials for pavement construction and research will facilitate the exchange of data and enable faster developments., Alternate title: Review of Asphalt (Concrete) Aging Tests in the US and Europe., Pavement Engineering

Aging is a crucial factor in pavement performance and being able to determine its effect on a mixture is necessary to link its initial properties to the properties over time in order to ensure the intended service life. This is becoming more important now that climate change leads to increased variation in weather conditions, while environmental considerations cause changes in the constituent materials that are used. As a result, past experience is becoming less reliable. In this paper, the USA and European approaches to aging are compared, showing that those contain the same test equipment and almost identical conditions for aging. This allows the exchange of data and experience. The current tests are suitable for binders and give an indication of the sensitivity to aging. For short term aging, Rolling Thin Film Oven Test (RTFOT) conditioning gives a reasonable indication of bitumen aging during asphalt concrete production and construction. This only holds for penetration grade binders during hot mix production and construction. For long term aging, because of the many variables involved, developing a single test method to characterize aging sensitivity seems impossible. However, using more elaborate protocols in existing, practical tests can provide more information and the necessary input for kinetic aging expressions. A pressure aging vessel (PAV) protocol for testing at two temperatures and time intervals, specifically at 90 and 100 degrees Celsius and for 20 and 40 hours, respectively, is suggested. Using the same conditioning in characterizing materials for pavement construction and research will facilitate the exchange of data and enable faster developments., Alternate title: Review of Asphalt (Concrete) Aging Tests in the US and Europe., Pavement Engineering

Technical specifications for the asphalt concrete properties are developed to be able to specify mixtures that will perform well in pavement applications. Being able to identify and determine properties related to pavement performance in practice is crucial for both road authorities and contractors, since it allows for design and risk management by determining design life times and reliability. However, the properties of Asphalt Concrete (AC) change over its lifetime and since most pavement layers last for a decade or more these changes are crucial in determining the performance in practice. For many of the standard materials the effect of aging is implicitly dealt with in the safety factors that also account for other effects such as the variation rest periods/healing and variations in traffic and weather in the design methods and specifications. Rapid changes in the materials used (increasing percentages reclaimed asphalt, bio-bitumen, rejuvenators, waste materials) and in the production of both bitumen (new refining methods resulting in different composition of bitumen) and asphalt concrete itself (warm mix asphalt, porous asphalt concrete, rubber asphalt mixtures) lead to increased uncertainty in the effects of aging. As a result, the uncertainties in pavement performance increase, which means the prediction of maintenance and the necessary budgets is getting more inaccurate. In order to maintain the ability to reliably design and maintain pavements and determine the most cost-effective solutions for a given situation, a better understanding of the aging processes and objective methods to take into account aging effects on material properties is needed. This need is widely recognized, in the USA the Mechanical Empirical Design Guide takes aging into account through aging tests on the bitumen used and in Europe CEN TC227 works on establishing a method to assess the aging sensitivity of asphalt mixtures. This symposium aimed at combining the existing information a, Structural Engineering, Civil Engineering and Geosciences

Technical specifications for the asphalt concrete properties are developed to be able to specify mixtures that will perform well in pavement applications. Being able to identify and determine properties related to pavement performance in practice is crucial for both road authorities and contractors, since it allows for design and risk management by determining design life times and reliability. However, the properties of Asphalt Concrete (AC) change over its lifetime and since most pavement layers last for a decade or more these changes are crucial in determining the performance in practice. For many of the standard materials the effect of aging is implicitly dealt with in the safety factors that also account for other effects such as the variation rest periods/healing and variations in traffic and weather in the design methods and specifications. Rapid changes in the materials used (increasing percentages reclaimed asphalt, bio-bitumen, rejuvenators, waste materials) and in the production of both bitumen (new refining methods resulting in different composition of bitumen) and asphalt concrete itself (warm mix asphalt, porous asphalt concrete, rubber asphalt mixtures) lead to increased uncertainty in the effects of aging. As a result, the uncertainties in pavement performance increase, which means the prediction of maintenance and the necessary budgets is getting more inaccurate. In order to maintain the ability to reliably design and maintain pavements and determine the most cost-effective solutions for a given situation, a better understanding of the aging processes and objective methods to take into account aging effects on material properties is needed. This need is widely recognized, in the USA the Mechanical Empirical Design Guide takes aging into account through aging tests on the bitumen used and in Europe CEN TC227 works on establishing a method to assess the aging sensitivity of asphalt mixtures. This symposium aimed at combining the existing information a, Structural Engineering, Civil Engineering and Geosciences