Interaction, rheological and physicochemical properties of emulsified asphalt binders with direct coal liquefaction residue based geopolymers

The use of solid waste and low-cost gel materials to replace or reduce the use of ordinary Portl and cement (OPC) in emulsified asphalt (EA) binder has positive significance for the comprehensive energy consumption and economic cost of cold mix asphalt (CMA) pavement. The proposed study investigates the interaction, rheological and physicochemical properties of emulsified asphalt (EA) with direct coal liquefaction residue based geopolymers (DG) by fluorescence microscopy tests, the pH test, asphalt conventional tests, dynamic shear rheological test (DSR), and Fourier transform infrared spectroscopy test (FTIR). The test results show that the reaction between DG mortar and EA particles was faster and more violent than that of OPC mortar, resulting in faster demulsification of EA. The added DG mortar increased the pH of the EA binder. Similar to OPC, DG decreased the penetration and ductility of EA evaporation residues, but increased its softening point. The addition of DG to EA changed the rheological properties of its evaporation residue, including complex modulus (G*) and phase angle (δ). Temperature sweep and frequency sweep test results show that DG was comparable to OPC in efficacy against EA residues, improving rutting resistance at the expense of fatigue performance. Complex modulus coefficient (ΔG^∗) and complex viscosity coefficient (Δη^∗) indicate that the interaction of EA-DG is stronger than that of EA-OPC. FTIR analysis showed that the interaction between DG and EA is linked as a chemical bond.