Paving industry sector faces nowadays different challenges as the need to have less maintenance, be more silent and more environmental friendly. The use of crumb rubber (CR) derived from end‐of‐life tires (ELTs) in bituminous mixtures replies to all these needs. For about 50 years the paving industry has been trying to take advantage of the elastomeric material and of the carbon black and silica included in recycled tires.
Those elastomeric materials are know to improve elastic recovery on bitumen and the carbon black and silica improve aggregate interlock however its implementation has not been extended and for example, in Italy this type of reuse is currently chosen for only 3% of total ELTs and the same scenario repeats in many other EU countries.
The main barriers that prevent its wide implementation are:
- A crumb rubber alone cannot be placed directly into the mixes (dry method) in significant qualities because it will swell and absorb the bitumen causing raveling in the roads
- The wet method (about 20% crumb rubber blended with bitumen and reacted over 1 hour at about 175 C) works well but requires that every contractor buys expensive equipment… around 700 000 USD (only cost effective for large projects)
- If crumb rubber is used in terminal blends it is essentially a waste of product because over time it becomes all digested. Actual improvements on mix properties are only a fraction of what they could be.
The solution proposed by SILENT RUBBER PAVE 100% industrial consortia to overcome these barriers is the use of use of reacted and activated rubber that can be used directly into the plugmill of a contractor’s plant.
The project objective is to facilitate the commercialization of RARX technology that has already demonstrated at low scale high benefits in the mechanical characteristics of road pavements as well in the reduction of the acoustic contamination of road traffic. Moreover, this technology has added environmental benefits as it makes use of used tyres.