Preparation Method of Waterborne Epoxy and the Properties of Its Modified Emulsified Asphalt

Micro-surfacing is considered as an effective and economical preventive maintenance technique for asphalt pavement. Its performance largely depends on the material compositions of emulsified asphalt binders. To overcome the deficiencies of ordinary micro-surfacing, waterborne epoxy resin emulsified asphalt (WEREA) micro-surfacing can significantly enhance its pavement performance. This work investigated the preparation of waterborne epoxy resin emulsion (WER), solidification behavior, and rheological properties of the solidified WEREA (S-WEREA) by phase inversion method, viscosity, fluorescence microscopy (FM), Fourier-transform infrared (FTIR), and dynamic shear rheometer (DSR) tests, respectively. The results indicated that the optimal preparation conditions of WER were determined as SDS:Span-80 = 5:13 (HLB value 14.2), a 12% emulsifier dosage, a 4712 s−1 shear rate, and a 60 °C preparation temperature, based on the evaluation of laser particle size for all specimens. The viscosity, FM, and FTIR tests exhibited that a strong chemical reaction occurred between epoxy resin and curing agent to form abundant crosslinked structures and new functional groups, contributing to improving the high temperature stability of S-WEREA. Dynamic shear rheometer (DSR) tests, including frequency sweep, multiple stress creep and recovery (MSCR), and linear amplitude sweep (LAS), indicated that a 15% WER content could balance the high-temperature deformation resistance and anti-fatigue performance, while excessive WER could adversely affect the low-temperature performance of S-WEREA and also lead to macroscopic phase separation at high-temperature. This study is expected to lay an experimental foundation for the wide application of WEREA in micro-surfacing.