Impact of constituent migration on colloid structure and rheological characteristics of emulsified asphalt with self-crosslinking modifiers

As a kind of environmentally friendly and energy saving material, asphalt emulsion was increasingly applied in the infrastructure construction industry. However, emulsified asphalt tended to face the problems of cohesive and mechanical strength deficiency, even if styrene-butadiene rubber/styrene-butadiene-styrene, modification had been performed. The waterborne additives with self-crossed characteristic showed a potential advantage on application. In this study, waterborne acrylate and polyurethane were investigated to further enhance properties of emulsified asphalt, as a novel modifier. The change of chemical constituent during the emulsion-additives interaction was firstly characterized by gel permeation chromatography (GPC) test. The dynamic shear rheometer (DSR) tests were carried out to evaluate the high-temperature characteristics comprehensively, involving temperature sweep, frequency sweep, steady shear viscosity and master curve tests. The modification mechanization was discussed according to the model of constituent migration in colloid structure of modified asphalt with additive. It released that the difference of polymer networks densities in styrene-butadiene rubber modified asphalt emulsion would cause embrittlement, while the combination of styrene-butadiene-styrene with cationic acrylate would present synergy effects in the colloid structure of emulsified asphalt. Finally, statistical analyses were conducted to evaluate the correlation among different rheological indices. The test results revealed that waterborne acrylate and polyurethane presented a positive effectiveness to modify asphalt emulsion, with enhanced performances for cold binder. [Display omitted]