Mixtures with Reacted and Activated Rubber from Recycled Tires

Description

Mixtures with Reacted and Activated Rubber from Recycled Tires

Jorge Sousa, Luís Quaresma, George Way, Francisco Silva

ABSTRACT. The wet method technology of using crumb rubber from recycled tires as a modifier of asphalt (bitumen) binder has been successfully used in crack sealing, spray applications (chip seals) and hot mix asphalt for at least 50 years starting in the 1960’s in Arizona and California. The crumb rubber wet process is a practical means of providing environmental, economic, sustainable, and safety of using crumb rubber from recycled tires using the wet method technology widely used in societal benefits. New imaginative and innovative engineering technology concepts have led to the development of a new crumb rubber semi- wet method material. The new semi-wet method employs reacted and activated rubber (RAR). The RAR semi-wet method has demonstrated a product capable matching and surpassing the performance of traditional hot mix asphalt and the traditional crumb rubber method asphalt. Basically, RAR consists of pre-treated and pre-reacted rubber that can be used directly in a mix plant just like a “filler” thus it is easy to handle and requires no special equipment for blending crumb rubber and asphalt and no additional heat source. The RAR dry filler when it meets hot asphalt amalgamates in such a way as to become like the traditional crumb rubber method asphalt rubber. The RAR is superior from the traditional crumb rubber method since it can be used at higher percentages. To ensure the quality and take advantage of the unique nature of RAR new specifications. These specifications encompass a broad range of quality measures to better enable a wide use by road departments. This paper introduces the concept and some experiences of mixes with RAR and presents how the added flexible fatigue resistance of those mixes leads to great environmental benefits. It introduces key concepts that can be the basis of specifications that can be used by road departments to ensure, not only that the crumb rubber is properly reacted and treated, but that the mixes have adequate bitumen and RAR to satisfy flexural/reflective fatigue.

KEYWORDS: reacted and activated rubber, fatigue life, crumb rubber reacted and activated rubber, fatigue life, crumb rubber.