Rubberized Asphalt Mixtures With Reacted Activated Rubber (RAR): The Semi-Wet Way

CIRTEC, Spain

Abstract: For more than twenty years many works have been developed inside the field of asphalt mixtures to add crumb rubber powder from end life tires (ELT’s) as a reusing way of a material that has shown its properties as an additive for improving technical performance of neat bitumen or binder and own asphalt mixes. There has been progress in several ways and technologies to incorporate this additive effectively and take advantage of the improvement and enhancing that crumb rubber gets to the performance of asphalt mixes, besides the environmental component and sustainability involving the use of a product obtained from shredding used tires at the end of its useful life. The evolution of these technologies has given its last step with the appearance of RARx, a pre-treated crumb rubber manufactured with a high proportion of crumb rubber powder from used tires and the addition of other additives, and whose main innovation lies in the treatment of pre-digestion made to crumb rubber on an industrial scale. This type of pre-treated products offers all the advantages and guarantees of modification for “wet way”, taking the ease of use and dosage in producing asphalt mixes in asphalt plants through a “dry way”, as one more additive. This new “semi-wet way” through RARx is a definite boost for employing in large amounts crumb rubber in asphalt mixes, solving the issues (times of digestion, decantations during transport and subsequent storage, piping and mechanical equipment obstructions, ...) that have been presented so far by two mentioned ways, wet and dry. High percentage of crumb rubber used in RARx production allows asphalt rubber mixes to reach the target of sustainability and circular economy on roads.