Effect of Mineral Filler Characteristics on Asphalt Mastic and Mixture Rutting Potential

Abstract

This study, part of the NCHRP 9–45 Project, analyzed the effect of mineral filler properties on asphalt mastic and the rutting potential of asphaltic mixture. The mineral filler properties were characterized by four tests: Rigden voids (RV), fineness modulus (FM), calcium oxide (CaO) content, and methylene blue value. The rheological properties of asphalt binder and mastic were characterized with the use of apparent viscosity and multiple stress creep recovery tests. Dynamic modulus and flow number tests were conducted to examine the asphaltic mixture rutting potential. The tested mixtures included several variables: four asphalt binder types, including virgin and polymer modified; two aggregate gradations; and a selected group of fillers. The study concluded that asphalt mastic performance was significantly affected by the fractional voids in the filler and possibly by the CaO content and FM. This effect, however, depended on binder type. On the one hand, the styrene–butadiene–styrene modified binder showed the strongest effect as a result of the mineral filler inclusion when tested as mastic. On the other hand, RV and CaO content showed relatively greater correlation with the mixture rutting potential, as compared with other filler properties. Addition of RV improved the prediction models for dynamic modulus and flow number. The effect of RV on the mixture rutting potential was more pronounced for the coarse mixture than for the fine mixture.

Etchable iron content (FETCH) proposed as the missing parameter for the better prediction of asphalt mastic stiffening

“…The calcium oxide content, proposed previously as a chemical parameter in stiffening [21,35], was found somewhat indicative of mastic stiffening inflicted by the filler, but it differentiated between only very different materials such as limestone and granite. When comparing granites and fly ashes, the CaO or CaOetch (calculated similarly to FETCH) as indicators lost its sensitivity.…”

Rheological Characterization of Warm-Modified Asphalt Mastics Containing Electric Arc Furnace Steel Slags

“…Therefore, this study is addressed to the assessment of rheological properties of mastics, that is, the blend of bitumen and filler, since it is well known that the major distresses in bituminous pavements are principally related to mastic performance. In fact, the filler mainly stiffens the bitumen decisively influencing, as a function of its nature and composition, the mechanical properties of asphalt mixtures in terms of cracking and rutting resistance [25][26][27][28][29][30][31][32].…”

Influence of Mineral Fillers and Their Fractional Voids on Mastic Rheological and Mechanical Properties

“…As discussed by many authors (Zeng and Wu 2008;Faheem and Bahia 2009;Delaporte et al 2008;Wang et al 2011;Yi-qiu et al 2010) the stiffness of the mastic affects the ability of the mixture to resist permanent deformation at higher temperatures, influences stress development and fatigue resistance at intermediate temperatures, and influences stress development and fracture resistance at low temperatures. Mineral filler fractional voids value has been used as an indicator of filler stiffening effect since the introduction of the test by Rigden in 1947.…”