Mechanism of Crumb Rubber Modifier Dissolution into Asphalt Matrix and Its Effect on Final Physical Properties of Crumb Rubber–Modified Binder

Abstract

Modification of asphalt by crumb rubber modifier (CRM) is mostly done through exchange of components between asphalt and CRM. At 160°C and 10 Hz, CRM absorbs aromatics of asphalt and swells; however, at 220°C and 50 Hz, CRM dissolves into the asphalt; this process leads to the release of different components of CRM including carbon black, fillers, and polymeric and oily components. Depending on interaction conditions, CRM dissolution is performed differently, and therefore the state and role of the released components can be different. In this research different mechanisms of dissolution of one size of CRM in asphalt matrix and their effects on property development of modified asphalt were studied by using different analytic techniques, including dissolution test, dynamic shear rheometer (DSR), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. Dissolution test results in combination with DSR results indicate the state and the role of CRM particles in the matrix, while TGA and FTIR spectroscopy show the type and amount of released components from CRM. The results reveal that for the materials used in this study interaction temperature is the main factor affecting the mechanism of dissolution of the CRM particles and consequently defines the role of the released components of CRM in asphalt matrix. DSR results indicate that during interactions at 190°C (intermediate interaction temperature), released components are more effective on physical properties of asphalt than are released components during interactions at 220°C (high interaction temperature).

Influence of Guayule Resin as a Bio-Based Additive on Asphalt–Rubber Binder at Elevated Temperatures

“…Recent studies in this regard have focused on the effect of material parameters (asphalt type, as well as CRM type and size) and interaction parameters (temperature, speed, and time). Some researches declared that temperature is the main interaction parameter affecting the CRM dissolution in asphalt-rubber binders [16,17]. A 190 • C interaction temperature has the potential to develop the liquid phase of the asphalt rubber binder [16,17].…”

“…Some researches declared that temperature is the main interaction parameter affecting the CRM dissolution in asphalt-rubber binders [16,17]. A 190 • C interaction temperature has the potential to develop the liquid phase of the asphalt rubber binder [16,17]. Besides, a 3000 rpm interaction speed has the potential to result in a more homogenous asphalt-rubber binder [16,17].…”

“…A 190 • C interaction temperature has the potential to develop the liquid phase of the asphalt rubber binder [16,17]. Besides, a 3000 rpm interaction speed has the potential to result in a more homogenous asphalt-rubber binder [16,17]. The CRM was difficult to entirely dissolve in asphalt due to its cross-linked structure [18].…”

Correlation between multiple stress creep recovery (MSCR) results and polymer modification of binder

“…CRM increases the stiffness and elasticity at high service temperatures while at very low service temperatures stiffness is reduced. However, there is no established procedure for proper use of CRM and consequently obtaining an optimum modification of properties is difficult [21]. This difficulty is due in part to the lack of a test sensitive to polymer modifications impact on performance.…”

Pulverization of end-of-life tires by ultra-high pressure water jet process

“…Among the above applications, CR has shown specific advantages over traditional materials, especially in crumb rubber modified (CRM) asphalt binder and CRM polymer materials. CRM asphalt binder incorporated with CR has better thermal stability, fatigue properties, and rutting performance [19]. CRM natural rubber (NR) or styrene butadiene rubber blends are believed to have better mechanical properties and better aging resistance [20].…”