Mechanical and rheological properties of emulsified asphalt enhanced by waterborne resin and its modification mechanism

As an environmentally friendly road material, emulsified asphalt has been widely researched and applied in road engineering. To further enhance its performance quality, various types of single and composite modified emulsified asphalt were prepared using waterborne polyurethane (WPU), waterborne epoxy resin (WER), waterborne acrylate (WA) and styrene butadiene latex (SBR). The effects of different modifier types on the mechanical, rheological and fatigue properties of emulsified asphalt were evaluated through tensile, low-temperature impact, temperature sweep, bending beam rheological, linear amplitude sweep, and other tests. Their microscopic and thermal properties were studied by infrared spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetry. And the correlation between the various properties of the modified emulsified asphalt was analyzed. The results showed that WPU can improve the strength, toughness, viscoelastic and fatigue characteristics of emulsified asphalt, WA or SBR modified emulsified asphalt. WER can further enhance its cohesion, bonding, and adhesion properties. The tensile strength and elongation at breaking of WER(2.5 %) and WPU(22.5 %) composite modified emulsified asphalt reached 5.98 MPa and 1324 %. Physical crosslinking and chemical reactions coexist during the modification process. After modification, the molecular weight increased while the distribution became more concentrated. The TG curve shifted to the right, and the thermal stability and cross-linking density increased. Correlation analysis shows that the mechanical strength, bonding and rheological properties of modified emulsified asphalt can be improved by regulating its molecular weight and distribution, as well as optimizing the glass transition temperature of the system to improve its low temperature crack resistance and impact resistance.