Abstract
This study used the Multiple Stress Creep Recovery Test (MSCR) and the Flow number test to analyze the characteristics of asphalt rubber and its use in hot mix asphalt (HMA) regarding to their ability to withstand permanent deformation. MSCR tests were done in three commercial asphalt rubber and in the traditional asphalt binder 50/70. Flow number tests were performed in twenty four specimens of asphalt rubber mixtures and eight specimens of conventional asphalt mixtures. The results of these tests showed that all the asphalt rubber samples had lower compliance values (Jnr) in the MSCR test, which denotes that these modified binders improved the rutting resistance of HMA. This behavior was confirmed with flow number results, since the HMA produced with asphalt rubber had always higher flow number values, when compared to the conventional asphalt mixtures. The analysis of the data showed excellent correlation between Jnr values and FN values.
Highlights
The use of rubberized asphalts has been was doing for the past 50 years in the United States and for past 15 years in Brazil
The experience around the world shows that the rubberized hot mix asphalt (RHMA) has higher durability, since it has better resistance to fatigue cracking, to re*lective cracking and lower temperature susceptibility, withstanding better to permanent deformation
Aggregates sources, granitic and basaltic, and four asphalt binders were employed in this study which resulted in the analysis of 32 asphalt mixtures and Table 5 shows their characteristics
Summary
The use of rubberized asphalts has been was doing for the past 50 years in the United States and for past 15 years in Brazil. The original USA Superpave system selected the correlation between complex modulus and phase angle (G*/sinδ) as the parameter to estimate rutting resistance This parameter measured at low strain during oscillatory loading in the Dynamic Shear Rheometer (DSR) and could not accurately represent the ability of a modi*ied binder to resist rutting (FHWA, 2011). The Multiple Stress Creep Recovery (MSCR) test is the latest improvement to the Superpave Performance Graded (PG) Asphalt Binder speci*ication. In this test, higher levels of stress and strain are applied to the binder, better representing what occurs in an actual pavement, mainly at the stress of 3.2 kPa, (D’Angelo et al, 2007). The multiples stress creep recovery test and the *low number test were used to analyse the rutting properties of three commercial asphalt rubber available in Brazil. That the main objective was achieved: (1) the asphalt binder was tested before and after the aging; and (2) a wide range of hot mix asphalt with different gradation, different aggregates, containing the asphaltic binders characterized
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