Laboratory evaluation of emulsified asphalt reinforced with glass fiber treated with different methods

Emulsified asphalt (EA) is an environment-friendly paving material that is commonly used as the binder of the interlay stress-absorbing composite (ISAC) layer. Roughening the surface of glass fiber by chemical treating is an effective approach to improve the adhesion between glass fiber and EA. However, the effects of the fiber treatment method on the performance of fiber-reinforced EA (FEA) still remain unclear. In this study, glass fiber, which is commonly used in the ISAC layer, was firstly treated with six methods (three etchants in two concentrations). Fibers were then incorporated into EA to prepare FEA samples. Finally, laboratory tests, including Scanning electron microscope (SEM) test, Fourier-transform infrared spectroscopy (FTIR) test, contact angle test, surface tension test, dynamic shear rheometer (DSR) test, and direct tensile test, were performed to evaluate the changes in the physical and chemical properties of glass fiber, EA, and FEA. The experimental results indicated that etching roughened the surface of glass fiber, increased the adhesion work of EA-glass fiber and the fracture strength of FEA. In addition, it was found that the interaction between glass fiber and EA was physical bonding and the performance of FEAs depended on the glass fiber treatment method. Sulfuric acid with a concentration of 2 mol/L was recommended as the optimal glass fiber etchant.