Performance analysis of sustainable asphalt mixtures modified with rubber and RAP.

Description

Performance analysis of sustainable asphalt mixtures modified with rubber and RAP.

Alarcón Ibarra, Jorge1, Mateos, Angel2, Bandala Vázquez, Hugo3, Estrada Cortez, Jorge Armando4.
1. Universidad Michoacana de San Nicolas de Hidalgo; Michoacán, México.
2. University of California Pavement Research Center; Berkeley, California.
3. Neotech Asphalt; Guanajuato, México.
4. Neotech Asphalt; Michoacán, México.
1. jorge.alarcon@umich.mx
2. angel-mateos@berkeley.edu
3. hbandala@neotechasphalt.mx
4. Ing.jaec@icloud.com

ABSTRACT. The practice of pavement recycling has focused primarily on the reclaimed asphalt pavement (RAP), incorporating fractions of this recovered material into the production of new mixtures. On the one hand, this incorporation of RAP into new mixes represents a positive environmental benefit; on the other hand, it significantly stiffens new mixes that incorporate RAP, making them susceptible to fatigue cracking. To mitigate this effect, a balanced design is required by incorporating rejuvenating additives or extraordinary percentages of asphalt content. Meanwhile, this helps reduce the fatigue susceptibility of a mix with RAP; the mixtures often reduce their resistance to permanent deformation, making the process of designing a mix with RAP and these types of additives complex. To analyze the abovementioned problems, the University of California, through its Pavement Research Center, in collaboration with the CalTrans and CalRecycle departments of the California state government, evaluated asphalt mixtures composed of RAP and the different forms of rubber incorporation. This article describes the results of this analysis, which evaluated mixtures with RAP and rubber, the latter being incorporated both by the wet and dry methods. It is demonstrated that predigested rubber, incorporated by the dry method, represents the best alternative to improve the cracking tolerance index (IDEAL-CT), as well as its resistance to permanent deformation in asphalt mixtures with RAP. This comparison allows exploring the implementation of sustainable asphalt mixtures, considering the addition of recovered material from aged pavements and rubber from end-of-life tires.

KEYWORDS: predigested rubber, RAP, IDEAL CT, mixtures with rubber, sustainable pavements, pavements recycling, balanced design.