Comparative analysis of the performance of asphalt concretes modified by dry way with polymeric waste

Abstract

An asphalt concrete has been modified by adding four polymeric wastes: polyethylene (PE) from micronized containers, polypropylene (PP) from ground caps, polystyrene (PS) from hangers and rubber from end-of-life tyres (ELT). These polymeric wastes were selected according to their availability, homogeneity and economic criteria considering the big amount of material required to build a road. The dry method has been used to modify the bituminous mixture due to its simplicity and the possibility to be carried out in any asphalt plant without important modifications. This is very important in order to spread the process and recycle the polymeric waste in the same place where it is produced, hence improving the environmental impact. The reference asphalt mixture and the four modified asphalt concretes have been analysed separately and their performance compared, evaluating their resistance against plastic deformation, stiffness, fatigue resistance and workability. The Master curve and the Black diagram of the mixtures were also calculated. The results showed that the use of polymeric wastes significantly increased the stiffness of the reference mixture in all cases, but especially when PE, PP and ELT were used. However, none of these materials significantly modifies the fatigue behaviour of the reference mixture. Regarding the resistance against plastic deformation, the use of both PE and ELT led to an increase of the resistance, whereas PP did not modify it and PS decreased it. As for workability, the energy of compaction of the modified mixtures did not suffer any important change. Therefore, according to the results obtained, PE, PP and ELT can be used to modify asphalt mixtures since they improve or do not change their properties. On the other hand, PS should be further studied because of the contradictory results obtained, and only when plastic deformation is not a problem this material could be used.

Reclaimed Polymers as Asphalt Binder Modifiers for More Sustainable Roads: A Review

“…As previously mentioned, polyethylene is a plastomer that softens to flow when subjected to warming, and becomes solid and rigid when the temperature decreases. The melting point ranges between 110 and 120 • C for LDPE [23][24][25]; around 125 • C for LLDPE [26], and between 130 and 149 • C for HDPE [15,27,28]. Those temperatures are below the temperature range that is commonly used in the production of hot asphalt mixtures.…”

“…The dry method is simpler and it can be applied in any asphalt plant without major modifications. This favors the use of this modification technique, facilitating the employment of recycled polymers [14,15]. However, the majority of the published studies have preferred the use of Sustainability 2019, 11, 646 3 of 20 the wet process [11,16,17], as it leads to a larger degree of modification of the binder and; therefore, to a better use of the reclaimed polymers (RP) to improve its properties.…”

Using Sustainable Oil Shale Waste Powder Treated with Silane Coupling Agent for Enriching the Performance of Asphalt and Asphalt Mixture

“…The main objective of sustainable development is to use natural resources in the most optimized way so that, environmental and socioeconomic issues are minimized [15][16][17]. In the past few years, studies regarding alternative environmental friendly materials in asphalt pavement to improve its mechanical properties have been conducted [18][19][20][21].…”

Characteristic of Coconut-Shell Ash as Filler and LDPE Plastic Waste as Substitution Materials of Porous Asphalt Mixtures

“…Several literature studies and research related to CA and LDPE found that the asphalt mixture characteristics that use these materials still meet the requirements set by Bina Marga (2014) and AAPA (2004) [3][4][5][6][7][8][9][10][11][12].…”