Effect of the construction process on the performances of asphalt paving mixes with crumb rubber from scrap tires

This paper presents the results of an experimental study on the use of CRM (Crumb Rubber Modifier) in bituminous mixtures for asphalt pavements, using a Dry Process. Employing experimental methods capable of ensuring that the mixtures obtained and the stress conditions that they undergo in pavements are representative, we clarify some aspects relating to the design and production of mixtures; we also show the effects of the bitumen-rubber interaction on mechanical performances (fatigue resistance and rutting). Among the various factors involved in manufacture, a particular investigation was carried out on the effects of asphalt content, mixing temperatures and mixture compaction. The experimental results show that the addition of rubber to bituminous mixtures with a Dry Process has effects on the physical and mechanical properties of bituminous mixtures that are similar to those given by the use of polymer-modified bitumens (thermoplastic elastomers, SBS type).