The Use of Cryogenic Crumb Rubber in the Cold Recycling Technique

Abstract

In the recent years, recycling has become one of the most attractive pavements rehabilitation alternatives and different recycling methods are now available to address specific pavement distresses and structural needs. Cold recycling is an economically efficient and environmental-friendly method for producing bituminous layers of adequate strength. This technique has been successfully used in Italy during the past 15 years to rehabilitate or upgrade many thousands of kilometers of highways and motorways’ pavements. Currently a wide range of materials can be used and consequently large is the number of variables to be considered in the mixdesign process. Being this a relatively new technique, new products are continually introduced or developed for recycling purposes. The main objective of this study is to investigate and evaluate the effects of crumb rubber, cement and bitumen proportions on the engineering properties of fully recycled cold mixes. In fact, the experimental plan includes the use of various quantities of Cryogenic Crumb Rubber (CCR) in mixtures containing 100% of Reclaimed Asphalt Pavement, bituminous emulsion and Portland cement. Thanks to the new European and national regulations, the use of recycled rubber in road construction applications has been growing so far and this application could represent a valid alternative to the classical use of rubber in HMAs.