Experimental Investigation of the Rheological Properties, Interaction, and Microstructure Characteristics of Emulsified Asphalt with Red Mud–Based Geopolymer

Abstract

To reduce energy consumption and save economic costs, waste-derived secondary resources can be considered as cement substitutes for emulsified asphalt. Considering emulsion type and red mud–based alkali-activated materials dosage and curing time, this study determined the feasibility of using red mud–based geopolymer to replace the commonly used cement in emulsified asphalt. Experimental tests, including pH tests, optical microscopy tests, dynamic shear rheological (DSR) tests, and Fourier-transform infrared (FTIR) spectroscopy tests were performed to characterize the rheological properties, interaction, and microstructure characteristic of red mud–based geopolymer emulsified asphalt composite binder (REACB). Cement emulsified asphalt composite binder (CEACB) was selected for comparison. The pH test and optical microscope tests demonstrated that the influence of red mud–based geopolymer on demulsification speed of stearyl trimethyl ammonium chloride (STAC) emulsion was greater than that of sodium dodecylbenzene sulfonate (SDBS) emulsion. The dynamic shear rheological test results showed that with the increase of curing time and red mud–based alkali-activated materials dosage, both the deformation resistance and the elastic recovery ability of REACB were improved, and the interaction ability between red mud–based geopolymer and SDBS emulsified asphalt gradually became stronger than that of STAC emulsified asphalt. Moreover, geopolymerization reactions in two kinds of REACB were proved using stretching vibration peaks of the asymmetric functional group T-O-Si. This study will promote the utilization of red mud–based aluminosilicate waste in emulsified asphalt.