Characterization and rheological behavior of asphalt binder modified by a novel cyclic borate ester additive

Abstract

• Asphalt binder was modified novel boron-containing additive named cyclic borate ester (CBE). • CBE additive was used into an asphalt binder in the ratios of 1%, 2%, 4% and 6% (w/w). • 1 H NMR, FTIR, SEM, TG/TDG and DSR tests were applied. • CBE additive interacted with asphalt’s chemical structure electro-statically. • CBE enhanced the elastic property of asphalt binder. In the current study, the synthesis of a novel additive containing boron and its inclusion in asphalt binder was completely achieved under chemical laboratory conditions. Following this objective, the structural analyses of the additive containing boron, namely Cyclic Borate Ester (CBE), and the modified asphalt binders were examined. The asphalt binders were blended with CBE additive in 1%, 2%, 4%, and 6% (w/w) ratios at each stage of the experiment. The elemental analyses of CBE were performed using the Fourier transform infrared (FTIR) spectroscopy test, the thermogravimetry (TG), and the proton nuclear magnetic resonance ( 1 H NMR) spectroscopy test. The mechanisms of the modification in the modified asphalt binders were researched using FTIR while their microstructures and thermal degradation behaviors were analyzed via scanning electron microscopy (SEM) and TG tests. In the analyses the rheological behaviors of the blends were investigated by the temperature-frequency-amplitude sweeps in dynamic shear rheometer (DSR) test. According to the experimental results, it was seen that there was no phase separation between CBE and the asphalt matrix. There was an electrostatic interaction between asphalt and CBE’s hydrocarbon chain. Accordingly, it was observed that the rutting resistance and elastic characteristics of the base asphalt binder investigated in the study were increased by including CBE.