# A Practice for the Application of Waste in Road Asphalt Pavements in an Eco-Friendly Way
###### Abstract  
The integration of circular economy principles in the design of road pavements raises the problem of obtaining high-performance asphalt mixtures for reduction of waste and environmental pollution compared to traditional solutions. In this study, the base and binder layers of road asphalt pavements were prepared by using reclaimed asphalt pavement and construction and demolition waste as coarse aggregates, while jet grouting waste and fly ash served as fillers. A leaching test was performed for the marginal materials, after which the engineering performances of the designed asphalt mixtures were investigated through laboratory tests. A life cycle assessment methodology was applied to determine the life cycle impacts of one cubic meter of each asphalt solution. Next, a multi-criteria decision analysis (MCDA) was performed for the solutions suggested for the binder and base layers. Finally, a sensitivity analysis was conducted to identify the most suitable MCDA solutions by varying the weights for a total of 24 different weight configurations. The results of this work revealed that the solutions utilizing jet grouting waste (in particular, the hot asphalt mixture for the binder layer and cold asphalt mixture for the base layer) were preferred to other traditional and alternative solutions in most decision-making scenarios. life cycle assessment; leaching test; eco-sustainable asphalt mixture; waste recycling; multi-criteria decision analysis +
Footnote †: journal: Applied Sciences  
Article  
A Practice for the Application of Waste in Road Asphalt Pavements in an Eco-Friendly Way  
3.87 times higher than that of virgin bitumen, while the related creep compliance decreased by 0.72 times. [PERSON] et al. [28] investigated the impact of using waste PET in binder class C320 by assessing the rheological properties of three modified bitumen with PET contents of 4%, 6% and 8% by the weight of the binder. It was found that 8% is the ideal PET content to reduce the bitumen susceptibility to cracking and deformation at high temperature. On the other hand, multiple waste materials are analysed as possible aggregates substitutes in asphalt mixes [29; 30; 31]. There is a wide range, including glass [32], scrap tires [33], concrete [34; 35], carbon black [36], ashes [37], ceramics [38], steel slag [39; 40; 41], recycled brick powder, ref. [42] and others such as jet-grouting waste [43] and fluorescent lamps waste [44]. [PERSON] et al. [45] evaluated the feasibility of replacing natural aggregate in emulsified asphalt mixtures (EAM) with recycled aggregates produced from construction and demolition waste (CDW). The mixture with 80% CDW in the grading curve showed better high-temperature performance but poorer low-temperature performance and moisture damage resistance compared to the traditional mixture made up of 100% natural aggregates. [PERSON] et al. [46] investigated the effects of reusing a particular type of CDW, namely the recycled concrete aggregates, whose size falls within a range 5-13 mm; four HMAs solutions were investigated with the substitution of 3, 6, 12 and 24% of the limestone aggregates with CDW. The results showed that four innovative mixtures returned an Indirect Tensile Strength Ratio (ITSR) on average 8% higher than a traditional HMA. Benefits of the alternative mixtures may be assigned to the residual inactivated cement of the recycled concrete particles, which activate the self-cement properties in contact with water. Actually, the most common technology to fabricate asphalt mixtures is the hot process, where the mixing phase (involving the aggregates, bitumen, and filler) occurs at the temperatures of 170-180 \({}^{\circ}\)C. With the aim of minimizing the negative impacts on the environment when the asphalt mixtures are produced, new technologies have become established: the warm and cold process [47; 48]. These two technologies reduce energy consumption by lowering the temperature at which asphalt mixtures are produced and laid [49].