Rheological Analysis of Asphalt Binders Modified with Hydrated Lime and Titanium Dioxide Nanoparticles

Abstract

The significant increase in traffic on paved roads has accelerated the deterioration of asphalt coatings. Because of this, the use of additives to modify the properties of the asphalt binder has been studied in order to improve the performance in relation to, mainly, permanent deformations and fatigue life. This work evaluates the changes in the rheological properties of CAP 50/70 modified with fractionated particles of hydrated lime and titanium dioxide nanoparticles, obtained from the use of a ball mill. For this purpose, the CAP 50/70 was modified with the addition of fractionated lime particles in the contents of 3%, 5% and 7% by weight of the pure binder and with 3% of ground nano TiO2 (180 nm). The modified samples showed less loss of mass in the short term aging, proving to be an antioxidant alternative. In addition, it was found that the modified binders provided an increase in G* (stiffness parameter) and, consequently, in the maximum Performance Grade (PG) temperature, allowing the use of the studied binders at higher temperatures. The binder modified with a content of 5% hydrated lime presented better results in the tests of permanent deformation (MSCR and LAS). The decrease in TiO2 granulometry increased the integrity of the binder and made it more sensitive to deformations under temperature variations, however, milled titanium dioxide showed a positive result in increasing the resistance of the asphalt binder to fatigue when compared to the binder with nano TiO2 220 nm. Finally, it was possible to establish that the addition of fractionated particles of hydrated lime to CAP 50/70 is a viable and effective technique that meets the requirements of DNIT for use in paving and that the incorporation of ground nano TiO2 (180 nm) attributed to the asphalt binder 50/70 higher working temperature in the field.

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Modificación de la mezcla asfáltica por vía seca mediante la incorporación de dióxido de titanio

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