Development of Rubber and Asphalt Binders by Depolymerization and Devulcanization of Scrap Tires in Asphalt

Abstract

Scrap tires in three forms-crumb rubber 60 minus mesh, crumb rubber 20 minus mesh, and buffed rubber-were subjected to depolymerization and devulcanization by applying heat, high shear, and a combination of both. Different reaction temperatures and times of reaction were applied. The reaction products were submitted to the testing of rheological properties by measurement of creep and recovery, viscosity, and some conventional tests. The amount of unreacted rubber and tendency to separation during the hot storage were also tested. Selected materials were evaluated according to SHRP specification and by the gel permeation chromatography. The results from the SHRP testing indicate that these materials are less temperature sensitive than conventional asphalts prepared from the same crude oil as the base asphalt. These materials were prepared in larger quantities and are being tested for their performance in paving mixes.

Improvement of Asphalt Binder by Recycling of Waste Tire Rubber

“…After that, the softening point was decreasing gradually this can be attributed to the particles of WTR were decomposed at temperature above 200 o C which causing reduction in binder viscosity. These results are agreement with finding of Zanzotto and Kennepohl (1996), Abdelrahman and Carpenter (1999) and Rahman (2004). …”

An investigation on using pre-treated tyre rubber as a replacement of synthetic polymers for bitumen modification

“…Also, the RTR-MBs cannot be stored for long periods after production because of the lack of compatibility between RTR and binder that leads to a phase separation problem. Many studies have been conducted to produce RTR-MBs that have reduced HTV and/or extended shelf life characteristics (Zanzotto and Kennepohl 1996, Glover et al 2000, Attia and Abdelrahman 2009, Akisetty et al 2011, Rodríguez-Alloza et al 2013. Some researchers utilized much severer curing conditions and fine rubber particles to overcome or alleviate these problems (Zanzotto and Kennepohl 1996, Glover et al 2000, Attia and Abdelrahman 2009).…”

Modul elastičnosti asfalta s bitumenom modificiranim gumenim granulatom kao vezivom

“…The advantage of the process is that the asphalt producer is able to modify the mixture independently from the bitumen producer. However, this process does not make use of potentially beneficial characteristics of the crumb rubber (or uses such characteristics to a minimum extent only), because the crumb rubber becomes an inactive filler in the asphalt mixture [3][4][5]. Although the dry process is used in international practice as widely as the wet one, no notable Hungarian research and experience about this process has so far been available.…”

“…This enables partial dissolution of the crumb rubber, which thus becomes an active modifying ingredient in the bitumen. This crumb rubber modified bitumen, which has beneficial engineering characteristics of both ingredients, is then used for asphalt mixtures [3,4,6]. Currently, the characteristics of asphalt mixtures made using the wet process are better compared to the dry process [7,8].…”