A Study on the Influence of the Chemical Nature of Fillers on Rheological and Fatigue Behavior of Bitumen Emulsion Mastic

Abstract

Cold Bitumen Emulsion (CBE) mixture technologies have been recently developed to lower pavement construction temperatures to reduce environmental costs and control gas emissions. Due to its poor early mechanical strength, active fillers (i.e., cement) have been used to obtain high early stiffness in order to have the potential for timely construction of the next layer. There is, however, a lack of understanding about the impact of active fillers on the viscoelastic behavior and fatigue damage resistance of CBE mastics. This study, therefore, aims to identify the influence of active fillers on the rheological properties and the resulting fatigue behavior of CBE mastic, supported by chemical analysis for the filler-bitumen emulsion. For this aim, bitumen emulsion was mixed separately with seven fillers/blended fillers to prepare the CBE mastics. Various experiments, including continuous pH monitoring tests (chemical reactivity of filler-bitumen emulsion), Strain Sweep (SS) tests, Temperature-Frequency Sweep (TFS) tests, Time Sweep (TS) tests, and Linear Amplitude Sweep (LAS) tests were conducted on the CBE binder and the prepared mastics. Results show that the rheological performance and the fatigue damage resistance depend not only on the filler inclusions but also on filler type and chemistry. On this basis, the rise in complex shear modulus and the decrease in the viscous component is associated with a significant enhancement in fatigue performance for specific fillers.

Current Research and Challenges in Bitumen Emulsion Manufacturing and Its Properties

“…Al-Mohammedawi and Mollenhauer 2020 conducted a study on the effect of the chemical nature of fillers (Both acidic and basic fillers) on the mechanical properties of cationic bitumen emulsion mastic. It was found that the filler with basic nature shows high reactivity in terms of pH value which is reflected in the fatigue and rheological performance which was believed due to the high filler/ bitumen emulsion compatibility [53], [64]. However, this study needs to be supported by microscopic and microstructure analysis in order to get more information about the surfactant and bitumen adsorption on filler particles.…”

“…surfactants' function can therefore be compromised when cement or mineral aggregate engages with cationic emulsions, due to increased pH; cement is particularly potent in affecting the pH of cationic emulsion. Consequently, the setting time and stability of bitumen emulsions are normally gauged concerning active filler [53]. It should be noted in this regard that some surfactants, including quaternary amines, retain their functionality even when pH changes [5].…”

Special Issue: Characterization of Innovative Asphalt Materials for Use in Pavement Design and Analysis

“…Twenty universities and scientific centres contributed with their original research papers to this Special Issue of Materials . The issues covered can be divided into five main topics: Characterization of recycled materials in asphalt concrete mixtures, such as waste of sanitary ceramics [ 23 ], crumb rubber (CR) from waste tires [ 24 , 25 , 26 ] and reclaimed asphalt (RA) [ 27 , 28 ]; Investigation of natural [ 28 ] or bio-based [ 29 ] materials used as rejuvenators in recycled asphalt applications; Study of rheological and fatigue behaviour of bituminous materials with [ 30 ] and without [ 31 ] the use of renewable bio-materials; Evaluation of lubricant characteristics of graphite nanoplatelets [ 32 ]; Fatigue life prediction model for materials employed on long-span steel bridge decks [ 33 ]. …”

Assessment of Fatigue Life and Stiffness of Asphalt Concrete After Implementation of Additives

“…It was also observed that the beneficial effect of lime addition in reducing rutting (which is a high temperature phenomenon) was realized more at higher mix temperatures. Al-Mohammedawi and Mollenhauer, [3] identified the influence of active fillers such as limestone, cement, ladle slag, and silica fume on the rheological properties and the resulting fatigue behavior of cold bitumen emulsion mastic. The assessment was supported by chemical analysis for the filler-bitumen emulsion.…”