A critical review of life cycle assessment benchmarking methodologies for construction materials

As it stands, the construction sector accounts for a significant proportion of global emissions. The majority of these emissions can be associated with material production. As a result, the importance of quantifying these environmental impacts is continually increasing. However, there is a current lack of guidance and methodologies regarding how to benchmark the impacts of construction products, and thus achieve more transparent environmental reporting and decision-making. Therefore, the aim of this study was to review engineering life-cycle assessment (LCA) literature and applicable standards to identify the key methodological variables required and the key steps for a sector-wide methodology. This was carried out via a bibliographic search for indexed, peer-reviewed journal publications and conference proceedings, project reports, and standards for constructed assets. From the search conducted, 23 documents and 4 standards were selected for review as relevant for this study. As a result, five key constituent methodological variables (study scope; model typology; benchmark approach; database selection; benchmark type) and three key steps (data collection; LCA; benchmark generation, with the option for Data Envelopment Analysis) were identified. Furthermore, considering the novel ISO 21678:2020, specific benchmark pathways were defined for the four types of benchmark values which can be obtained: limit, reference, short- and long-term. The definition of this set of steps, key methodological variables and the authors' recommendations for the construction sector constitute the first LCA benchmarking methodology on this field

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-related tests at three different aging levels. Results show that physical and rheological properties can be fully restored by the addition of the proper dose of rejuvenator, while the chemical composition should be investigated in more detail. Rejuvenated binders exhibit great long-term performance especially at high and low temperatures, but also show significant resistance against fatigue at intermediate temperatures

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, in this paper, fatigue resistance of extracted binders from high-RAP content mixtures and of RAP mortars (passing sieve with an opening size of 0.15 mm) were assessed and compared. Binders were extracted from asphalt mixtures manufactured with 30%, 60% RAP and rejuvenators. Mixtures recipes were then reproduced to manufacture mortars accordingly. Time sweep tests in stress-controlled mode were carried out on both materials (binders and mortars) and the resulting fatigue laws were compared. As a result, a strict correlation was obtained, leading to affirm fatigue-related properties of RAP mixture could be assessed by directly testing RAP mortars. This makes the recovery of RAP binders unnecessary. Moreover, a relationship between the two fatigue laws versus the percentage of fine particles in the mortar was found. This latter relationship allows determining the fatigue law of mortars corresponding to any percentage of fine particles and therefore corresponding to any percentage of RAP

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 authorities and NRAs. To do so, a questionnaire was sent to di erent NRAs and an online search was conducted to identify the ways that NRAs communicate their CE practices. Findings indicate that, although the majority of the NRAs are familiar with CE as a concept, not many actions have been taken so far towards its holistic implementation. Finally, there is a significant lack of CE expertise and communication within these bodies.European Union's Horizon 2020 Program under the Marie Curie-Sklodowska actions for research, technological development, and demonstration 721493CEDR Transnational Research Programm

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 bio-recycled asphalt mixtures, were produced, subjected to ageing and rheologically characterised. The results show that the rheological properties of binders’ blends seem adequate for their use, while the bio-recycled asphalt mixtures seem to have a faster ageing than conventional ones, hence their full-scale application still remains a concern

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 simulations. The overall prediction accuracy, when all the signals are considered, is between 4% and 8% for all materials. It can be concluded that material characterisation in lab as well as the selected models are well adapted to simulate actual loading state under a moving load, even for these non-conventional mixes. For temperatures lower than 25°C, elastic modelling appears to be sufficient for pavement structural design with the innovative materials tested here

Pavement life cycle management: Towards a sustainability assessment framework in Europe

Pavement Life Cycle Management is a 2-year international project aiming at supporting European National Road Authorities (NRAs) to introduce sustainability in their practices by providing training on Life Cycle techniques and a user-friendly package to support their widespread implementation. The first task in Pavement Life Cycle Management (PavementLCM) project is the creation of a Sustainability Assessment (SA) framework that complies with EN15643-5 and consequently include the three pillars of sustainability, use a life cycle approach and use quantifiable sustainability performance indicators. This paper presents the first steps towards the creation of the framework which includes the following steps: 1) review of the available Product Category Rules (PCRs) related to asphalt mixtures and pavement activities; 2) definition of the object of the assessment; 3) review and survey of NRAs practices of the main research efforts in Europe towards the definition of sustainability performance indicators

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 simulations. The overall prediction accuracy, when all the signals are considered, is between 4% and 8% for all materials. It can be concluded that material characterisation in lab as well as the selected models are well adapted to simulate actual loading state under a moving load, even for these non-conventional mixes. For temperatures lower than 25°C, elastic modelling appears to be sufficient for pavement structural design with the innovative materials tested her