Multi-Criteria Selection of Additives in Porous Asphalt Mixtures Using Mechanical, Hydraulic, Economic, and Environmental Indicators

Porous asphalt (PA) mixtures are more environmentally friendly but have lower durability than dense-graded mixtures. Additives can be incorporated into PA mixtures to enhance their mechanical strength; however, they may compromise the hydraulic characteristics, increase the total cost of pavement, and negatively affect the environment. In this paper, PA mixtures were produced with 5 different types of additives including 4 fibers and 1 filler. Their performances were compared with the reference mixtures containing virgin bitumen and polymer-modified bitumen. The performance of all mixes was assessed using: mechanical, hydraulic, economic, and environmental indicators. Then, the Delphi method was applied to compute the relative weights for the parameters in multi-criteria decision-making methods. Evaluation based on distance from average solution (EDAS), technique for order of the preference by similarity to ideal solution (TOPSIS), and weighted aggregated sum product assessment (WASPAS) were employed to rank the additives. According to the results obtained, aramid pulp displayed comparable and, for some parameters such as abrasion resistance, even better performance than polymer-modified bitumen, whereas cellulose fiber demonstrated the best performance regarding sustainability, due to economic and environmental benefits.This work and the APC are funded by SAFERUP! Project, from the European Union’s Horizon 2020 research and innovation program under, the Marie Skłodowska-Curie grant agreement No. 765057

Development of improved porous asphalt mixtures with high porosity levels

Porous asphalt (PA) mixtures are gaining wider acceptance in pavement construction due to their benefits in terms of road safety, noise mitigation and stormwater management. Increasing demands, such as those imposed by climate change, require the design of mixtures that provide enhanced functional properties, while keeping the same durability of conventional porous asphalt mixtures. This study proposes different experimental PA mixes with higher air voids content and suitable structural capability than a conventional PA mixture. The functionality of the mixtures was evaluated in accordance with total and interconnected air voids, while the mechanical performance was assessed in terms of raveling resistance both in dry and wet conditions, tensile strength, and moisture sensitivity. The binder drain down was also verified. In a first stage, the experimental results were analyzed through descriptive and inferential statistics tests. As multiple responses were obtained, principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were applied to explore the association pattern among the test results and experimental designs. The study concluded that PA mixes with air voids content of up to approximately 28% and admissible values of resistance can be designed. The use of polymer modified binder (PMB) and the inclusion of fibers and hydrated lime (HL) was essential for the formulation of the mixes

An experimental laboratory study of fiber-reinforced asphalt mortars with polyolefin-aramid and polyacrylonitrile fibers

Promising results have been found in the literature through use of synthetic fibers in hot mix asphalt. However, few research works have focused on studying the effect of these fibers at asphalt mortar scale. In this research, the reinforcing effect of polyolefin-aramid (POA) fibers and polyacrylonitrile (PAN) fibers is investigated in asphalt mortars through indirect tensile testing. Fiber-Reinforced Asphalt Mortar (FRAM) specimens were prepared with different fiber contents (0.1 wt%, 0.2 wt% and 0.3 wt%) and tested at three temperatures (15 °C, 0 °C, ?15 °C). Indirect tensile strength, fracture energy, post-cracking energy and toughness were the parameters obtained and analyzed from the test in order to understand the behavior of the different FRAM designs. Moreover, the failure types obtained were also analyzed. According to the experimental results, a significant improvement of strength at low temperature (?15 °C) was observed when adding 0.3% of POA or PAN fibers. Furthermore, the fracture energy properties were enhanced due to the addition of fibers.This work has received funding from the CEDR Transnational Road Research Program - call 2017 427 under the contract N. 867481, “Fostering the implementation of fiber-reinforced asphalt mixtures 428 by ensuring its safe, optimized and cost-efficient use (FIBRA)”. Scientific support from the 429 consortium partners University of Cantabria (Spain), Technical University of Braunschweig 430 (Germany), BAM (Netherlands) SINTEF and Veidekke (Norway) is gratefully acknowledged. 43

Life cycle assessment (LCA) and multi-criteria decision-making (MCDM) analysis to determine the performance of 3D printed cement mortars and geopolymers

A comparison between low-clinker cement and geopolymer mortars for their application in 3 D printing is discussed in this paper. The mortars are composed of materials with low environmental impact, such as cements with low clinker content, by-products of the industry and recycled aggregates. The developed mortars were both mechanically and rheologically characterized. The environmental impact was studied by LCA. To select the most suitable dosages, MCDM analysis was applied based on cost of materials, printability and LCA. Compressive strength was considered as a normalizing parameter for both the LCA and cost. The mortars showed good printability and suitable mechanical strength, being higher in the cement mortars. The LCA showed that the geopolymer mortars have a higher environmental impact due to the use of sodium hydroxide. Likewise, MCDM revealed that low-clinker cement mortars are at the top of the ranking, due to a lower environmental impact and lower cost of materials.This work has been co-financed by the European Regional Development Fund through the Interreg Atlantic Area Programme, under the project 3DPARE (EAPA_174/2016). This work reflects the authors’ opinion, so the authorities of the programme are not responsible for the use of the information here included

A multi-criteria decision-making analysis for the selection of fibres aimed at reinforcing asphalt concrete mixtures

In the last few years, fibers have been proposed as one of the most important additives for the development of reinforced asphalt mixtures. The optimal fiber selection is a very complex task, as an extensive range of criteria and alternatives have to be taken into account. Decision support systems have been applied in the construction sector, but not for selecting fibers for bituminous mixtures. To fill this gap, two Multi-Criteria Decision-Making Analysis methodologies for the selection of the best fiber to be used in Asphalt Concretes are presented in this paper. The Weighted Aggregate Sum Product Assessment (WASPAS) methodology and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) integrated with Fuzzy Analytic Hierarchy Process (FAHP) are used to evaluate the effect of various types of fibers on the mechanical performance of bituminous mixtures. Given the uncertainty involved, a stochastic simulation is proposed using the Monte Carlo method. A statistical analysis is carried out to verify the results obtained. Both methods of multi-criteria analysis were effective, with TOPSIS being slightly more conservative in the assignment of performance scores. Synthetic fibers proved to be a suitable option as did fibers with high tensile strength and elastic modulus