Evaluation of the Rheological Behavior and the Development of Performance Equations of Asphalt Composites Produced with Titanium Dioxide and Zinc Oxide Nanoparticles

Abstract

This research evaluated the rheological behavior of conventional asphalt binders modified with TiO2 and ZnO nanoparticles and proposed mathematical equations for performance prediction. First, composites were evaluated at high temperatures to investigate the Performance Grade (PG), non-recoverable creep compliance, and Aging Index (AI). Subsequently, the fatigue damage tolerance was determined at a temperature of 20 °C through the Linear Amplitude Sweep (LAS) test. At high temperatures, for both nanoparticles, stiffness gain was observed as the nanomaterial content increased, evidenced by the increase in the dynamic shear modulus. This resulted in an increase in the Performance Grade and reduction in non-recoverable creep compliance, leading to greater resistance to permanent deformations. Furthermore, it was found that nanoparticles were able to reduce the effects of oxidation of the asphalt matrix, corroborated by the reduction of the Aging Index (AI). Regarding the fatigue damage tolerance, for both nanoparticles, an increase in performance was observed at low deformation amplitudes and a decrease at high deformation amplitudes. Finally, the analysis of each rheological parameter allowed to define the mathematical equations capable of predicting the performance of conventional asphalt binders when modified with nano-TiO2 or nano-ZnO.

Aging Resistance Evaluation of an Asphalt Mixture Modified with Zinc Oxide

“…Additionally, ZnO presents a high specific surface area, facilitating the adsorption of light components on the binder [45]. The gain in binder stiffness due to ZnO is also explained by the high mechanical strength and structural stability of the nano-particles, which have been shown in rheology tests to increase rutting resistance [18,42].…”

“…Likewise, a material that has been showing a high chance of success in improving aging resistance is zinc oxide-ZnO [15][16][17][18][19]. ZnO is a colorless material with low toxicity [20], showing a high compatibility with asphalt binders [21][22][23], high conductivity, heat capacity, and chemical-thermal stability [24].…”

The Use of Zinc Oxide in Asphalts: Review

“…Staub de Melo et al [59] modified an AC 60 dmm (PG 58) with ZnO (3, 6, 9, 12, and 15 wt%). The modification was performed at a temperature of 150 ± 5 • C using a high shear mixture at a speed of 6000 rpm for 15 min.…”

“…The modification was performed at a temperature of 150 ± 5 • C using a high shear mixture at a speed of 6000 rpm for 15 min. Staub de Melo et al [59] used a DSR to measure the PG at high temperatures, then used aging index (AI) and non-recoverable creep compliance tests, as well as LAS (20 • C) tests. ZnO increased the stiffness, high-temperature PG, rutting, and aging resistance of the asphalt binder.…”