Resistance to Permanent Deformation of Asphalt Concrete with F-T Wax Modified Foamed Bitumen

Higher requirements concerning environmental protection and occupational health and safety entailed the development of new asphalt mix production technologies, characterized by production temperature lowered by 60 to 80 °C. In addition to environmental advantages, such bituminous mixtures also provide technological and economical benefits. The reference asphalt concrete AC 22W and experimental foamed bitumen asphalt modified with F-T wax was designed to respond to the requirements named above. The production and compaction temperature of the foamed bitumen asphalt was 95 °C (Half Warm Mix Asphalt). A traditional Hot Mix Asphalt was also produced for the purpose of comparison. The study investigated the effect of two factors: the amount of F-T synthetic wax (from 1.0% to 2.5% with an increment of 0.5%) and the amount of foamed bitumen (from 4.2 to 5.1, with an increment of 0.3%) on the development of permanent deformations in asphalt concrete, one of the most significant service parameters of the asphalt pavement. The results from the study indicate that the addition of F-T synthetic wax to the bitumen before foaming gives the asphalt concrete (produced at 95 °C) resistance to permanent deformations comparable to that of the traditional asphalt concrete, produced at a temperature of 160 °C.