Effect of Mineral Fillers on the Oxidative Aging of Asphalt Binders

Abstract

Aging of asphalt binders is induced by chemical or physicochemical changes during production of pavement and throughout its service life. Although binder aging in pavement always occurs while binders are in contact with aggregates and mineral filler, in most laboratory aging studies and in current specifications, asphalt binders are individually aged without accounting for aggregate induced interactions. Past research has had conflicting findings, as it attributes mitigating or catalytic effects to the presence of mineral fillers in asphalt binders with oxidative aging. Thus, in the present study it was hypothesized that evaluation of asphalt oxidative aging without taking into account the interactive effect of the presence of mineral fillers was inadequate as a specification tool. The effect of mineral fillers on oxidative aging of asphalt was investigated with accelerated aging of mastics (asphalt and fillers) in a pressure aging vessel (PAV) and by measuring the changes in stiffness and glass transition temperature ( Tg). The testing matrix included an aging evaluation of mastics containing different fillers, mineralogy, and surface area. The results showed that the low-temperature behavior of aged mastic could be modified by controlling filler concentration and type. The fillers acted as an agent adsorbing heavy fractions of asphalt binder and therefore reduced stiffness and changing Tg. During oxidative aging of asphalt binders and mastics, diffusion and adsorption mechanisms played a role in the rate of aging of asphaltic material. The results provided insight on the potential for selecting a mineral filler concentration and mineralogy type to reduce the impact of oxidative aging and possibly improve the service life of pavement.

Influence of the Mineral Powder Content on the Asphalt Aging Resistance in High-Altitude Areas Based on Indoor Ultraviolet Light Tests

“…Moraes and Bahia investigated effects of the mineral fillers on stiffness and glass transition temperature of PAV-aged asphalt binder. The results showed that a selected filler concentration and mineralogy type might reduce the oxidative aging of asphalt binder [31]. Zhang et al analyzed the effects of various material properties of filler, including filler particle size, SiO 2 content on asphalt-filler interaction ability, and found that the relative proportion between 'free asphalt' and 'structural asphalt' was significantly influenced by filler particle size [32].…”

Kinetics-based aging evaluation of in-service recycled asphalt pavement

“…In particular, air voids exert a notable influence on aging behaviors of asphalt mixtures (Mirza and Witczak, 1995;Luo et al, 2015). The chemical interaction of aggregates and asphalt binders also alter the mixture's susceptibility to aging (Sosnovske et al, 1993;Moraes and Bahia, 2015).…”

“…Aging activation energy of an asphalt mixture in a pavement structure is affected by the binder type, aggregate type, air voids, and location (Sosnovske et al, 1993;Mirza and Witczak, 1995;Luo et al, 2015;Moraes and Bahia, 2015). This means that the aging activation energy of an asphalt pavement is a net result of all these factors.…”

“…The may be related to the chemical interaction between aggregates and asphalt binder, a larger adhesive bonding helping mitigate aging (Sosnovske et al, 1993). In addition, it was found that the adsorption of asphalt components on to aggregates could help reduce the impact of oxidative (Moraes and Bahia, 2015). Air voids of an asphalt mixture and its location in a pavement structure affect aging in terms of the amount of oxygen available for the oxidation process.…”

Effect of Nanoadditives on Bitumen Aging Resistance: A Critical Review

“…This procedure is static and the absence of the rotating phase avoid artefacts related to the high viscosity of the binder. However, when approaching the PAV test in the presence of mineral fillers, many other aspects must be taken into account like the influence of the filler on the binder density [5][6][7] or its tendency to sedimentation during the PAV [8]. The latter will compromise the uniformity of the sample, thus changing its permeability to oxygen molecules and affecting the whole aging process.…”