Evaluación del efecto rejuvenecedor de bio-materiales sobre ligantes para mezclas con alto contenido de asfalto recuperado
The interest in using bio-materials in pavement engineering has grown significantly over the last decades due to environmental concerns about the use of non-recoverable natural resources. In this paper, bio-materials are used together with Reclaimed Asphalt (RA) to restore some of the properties of the aged bitumen present in mixtures with high RA content. For this purpose, two bio-materials are studied and compared to conventional and polymer modified bitumens. Blends of these materials with RA bitumen were produced and studied to simulate a 50% RA mixture. The rejuvenating effect of the two bio-materials on RA has been assessed and compared with the effect of the conventional binders. App…
European National Road Authorities and Circular Economy: An Insight into Their Approaches
The pavement engineering industry, having realized the significance of the impacts that it imposes on the environment through the production, construction and management of its products and assets, has been driven towards a more sustainable and circular way of operating. This has partly been through asphalt recycling, which is an area that many road authorities have prioritized. However, not all the National Road Authorities (NRAs) and/or sector stakeholders seem to be adequately familiar with the Circular Economy (CE) concept. This paper attempts to assist the transition of NRAs to a more circular way of doing business, by analyzing the current situation of CE within national/regional auth…
Life Cycle Assessment of Asphalt Mixtures with WMR
This study aimed at providing pavement specialists with international average values of greenhouse gas emissions (GHG) and energy consumption related to the manufacturing of asphalt mixtures (cradle-to-gate), with and without waste and secondary materials for roads (WMRs). In order to achieve this goal, TG leaders first referred to current standards to define a methodology for obtaining benchmark values according to ISO 21678:2020. Then, a data collection tool was designed and provided to a group of international partners to build a life cycle inventory for asphalt mixtures including data from materials up to plant manufacturing (A1–A3). Partners were asked to provide information for any ty…
Performance of a sustainable asphalt mix incorporating high RAP content and novel bio-derived binder
The recent drive to find ways to increase sustainability and decrease costs in asphalt paving has led researchers to find innovative ways to incorporate more recycled materials and bio-derived binders into mixes with varying success. A new novel bio-derived binder made from refined pine chemistry stabilised with a polymer can increase the sustainability of asphalt mixes while maintaining pavement performance. Laboratory performance testing was conducted on asphalt mixes containing 50% Reclaimed Asphalt Pavement (RAP) by mix weight and the novel bio-derived binder. Results show that the bio-derived binder outperforms the conventional 50/70 pen grade binder mixes with respect to resistance to…
Bio materials with reclaimed asphalt: from lab mixes properties to non-damaged full scale monitoring and mechanical simulation
Three innovative environmentally friendly pavement materials, designed with 50% of Reclaimed Asphalt and three different biomaterials (2 bio-additivated bitumens and 1 bio-binder), were produced in an industrial plant. These mixes were tested in lab and also at full scale using an Accelerated Pavement Test facility. The asphalt mix viscoelastic properties were measured in lab and their intrinsic viscoelastic response were simulated. These rheological models are used to simulate the pavement mechanical response using both elastic and viscoelastic multilayer codes. Hence, full scale measurement performed during the full scale test at an early stage (without damages) can be compared with these…
Reclaimed asphalt binders and mortars fatigue behaviour
Fatigue cracking is one of the most important failure mechanisms occurring in asphalt pavements, especially when mixtures incorporate considerable amount of rReclaimed asphalt pavement (RAP). In fact, aged binders contained in RAP generally make asphalt more brittle and specifically reduce fatigue resistance of the resulting asphalt mixtures. Binders and mortars play a key role in this phenomenon, considering fatigue cracking usually starts within these asphalt components. However, performance-related tests and specifications commonly regard binders and there are no sound methodologies allowing the use of mortars to predicting fatigue performance of asphalts containing RAP. For this reason,…
Intrinsic adhesive and cohesive assessment of the moisture sensitivity of bio-rejuvenated recycled asphalt binders
Alternative binders not derived from fossil fuels, known as biobinders, are opening new paths for multiple applications in road infrastructure. Biobinders, usually produced from bio-oils obtained from the processing of biomass and industry by-products, are tuneable materials whose properties can be adjusted to meet specific targets. For this reason, an interesting approach is to couple biobinders with Reclaimed Asphalt (RA) by taking advantage of their rejuvenating properties to design bio-asphalt mixtures with high-content RA and no additional virgin bitumen. Recent research has proven the feasibility of this approach through validation at full-scale (BioRePavation project). However certai…
Interpreting Life Cycle Assessment results of bio-asphalt pavements for more informed decision-making
Due to emerging climate challenges, engineers are looking to replace the conventional asphalt pavements by utilizing bio-materials combined with Reclaimed Asphalt (RA). However, there is insufficient record in the literature assessing their environmental performance. This study addresses the analysis of the results obtained from a life cycle assessment exercise of asphalt pavements containing bio-materials and RA within their binder courses, developed within the BioRePavation project. The aim is to analyze the environmental benefits achieved, by means of hotspot mapping and sensitivity analysis of the most impactful factors of their lifecycles. Two alternatives are compared to a conventiona…
A new procedure to determine the rheological properties of RAP binder and corresponding bituminous blends
Abstract In this paper, a new and simple approach to estimate the rheological properties of Reclaimed Asphalt Pavement (RAP) binder is proposed to overcome the limitations of the conventional extraction procedure. This method is based on Dynamic Shear Rheometer tests performed on mortars composed of RAP fine fraction and virgin binder, together with a new back-calculation solution. The properties of the bituminous blends of virgin and RAP binders are obtained with a modified Nielsen model. The Voigt model is then successfully used to estimate complex modulus and phase angle of the RAP binder from the properties of the back-calculated binder blend. This procedure would prevent the need of RA…
Linear viscoelastic properties of high reclaimed asphalt content mixes with biobinders
The use of high Reclaimed Asphalt (RA) content mixtures together with binders produced from renewable resources (biobinders) is one of the current challenges in pavement engineering research. On the one hand, RA has been used for decades, but there are still some concerns about its performance, especially when high contents are used (>30%). On the other hand, biobinders are relatively new materials, which have to be deeply characterised and studied in order to develop good practices for their use. In this paper, linear viscoelastic properties of biobinders and bio-mixtures manufactured with high RA content and biobinders are analysed and discussed. High-modulus mixtures with 50% RA were…
Towards 100 % recycling of reclaimed asphalt in road surface courses: binder design methodology and case studies
Reclaimed Asphalt (RA) has shown great potential to be reused in new asphalt mixtures, however its incorporation in top asphalt pavement layers is still very limited (10e30%). In fact, despite the advan- tages that its use implies, RA content in road pavement surface courses is still restricted in most countries due to mainly legislation limitations, but also some technical issues. This paper aims at being a step further to improve the latter by providing a methodology that allows producing fundamental inputs for confidently performing mix design of asphalt mixtures incorporating up to 100% RA. The methodology consists in an advanced preliminary binder's blend design that can be used with a…
Effects of Laboratory Aging on Properties of Biorejuvenated Asphalt Binders
This paper presents the results from a laboratory investigation on the effects of aging on the properties of two binders recovered from two different sources of Reclaimed Asphalt (RA) and additivated with a biorejuvenator derived from pine trees. It has been already proven that the rejuvenators are able to restore some of the properties of the aged binder present in the RA, but nowadays their effects into the long-term period are not well known. In this regard, the rejuvenated asphalt binders and a virgin binder, defined as a target, have been aged artificially to simulate short-and long-term aging. All binders have been studied conducting physical, chemical, rheological, and performance-re…
Binder and Mixture Fatigue Performance of Plant-Produced Road Surface Course Asphalt Mixtures with High Contents of Reclaimed Asphalt
The aged properties of Reclaimed Asphalt (RA) binders are one of the main factors working against their utilisation in high-RA content (>
Effect of two novel bio-based rejuvenators on the performance of 50% RAP mixes - a statistical study on the complex modulus of asphalt binders and asphalt mixtures
An experimental study was conducted to evaluate the effectiveness of two bio-additives as rejuvenators on the properties of asphalt mixtures containing 50% RAP and their binder constituents containing 37% RAP binder. Before mixing, the rejuvenators were blended with fresh bitumen and the extracted and recovered RAP bitumen, and changes in the rheological properties of the binders were assessed using performance grading (PG) criteria. The results showed that both rejuvenators could improve the low-temperature performance of the aged RAP binder and restore its low-temperature properties. Master curves for the unaged, RTFO-aged, and PAV aged blends were constructed using both the Christensen-A…
Rheological investigation on the ageing performance of bio-recycled asphalt binders and mixtures
The current need to move towards more sustainable technologies in the construction sector has promoted the investigation of using alternative materials in asphalt mixtures for pavements. Biomaterials, used as biobinders, have shown their potential as partial replacement of bitumen in asphalt mixtures as solution to decreasing the demand for fossil-fuel-based binders as well as CO2 emissions. However, more research is needed to increase the replacement of bitumen in asphalt mixtures. In this investigation,biobinders are used as full replacement of virgin bitumen and as recycling agent within asphalt mixtures with high Reclaimed Asphalt (RA) content. Blends of biobinders and RA binders, and b…
Optimisation of liquid rubber modified bitumen for road pavements and roofing applications
Abstract Polymer Modified Bitumens (PMBs) are largely used for pavement and roofing membranes applications with Styrene-Butadiene-Styrene Block copolymer (SBS) playing a major role in both markets despite its constantly increasing price due to the rising demand for quality bitumen modifiers. On the other hand, there is an increasing trend of recycling end of life tyres generating Recycled Tyre Rubber (RTR) at affordable price. This investigation aims at engineering a modified bitumen with a combination of Liquid Rubber (LR), a homogeneous blend of 50–70% RTR pre-processed in combination with heavy oils, and a wax denominated Ethylene Bis Stearamide (EBS). In the first phase, the effect of L…
Machine learning techniques to estimate the degree of binder activity of reclaimed asphalt pavement
Part of this research was funded by the project RTI2018-096224-J-I00 that has been cofounded by the Spanish Ministry of Science and Innovation, inside the National Program for Fostering Excellence in Scientific and Technical Research, National Subprogram of Knowledge Generation, 2018 call, in the framework of the Spanish National Plan for Scientific and Technical Research and Innovation 2017-2020, and by the European Union, through the European Regional Development Fund, with the main objective of Promoting technological development, innovation and quality research. Part of this work was financially supported by the Italian Ministry of University and Research with the research Grant PRIN 20…