LAUSR

Abstract Using bio-oil to replace petroleum-based asphalt binder in pavement construction can minimize the demand for crude oil, but different sourced bio-oil may have a different effect on the asphalt binder’s properties, especially on the moisture damage resistance of pavement. Our previous research found that bio-oil from corn can increase moisture susceptibly of the asphalt binders, so this paper studies the variance of binder’s moisture susceptibly due to the addition of bio-oil and chemical modification of bio-oil to improve its hydrophobicity. Chemical characterization by elemental analysis, SARA analysis, Fourier transform infrared (FTIR) spectroscopy, and gas chromatography-mass spectrometer (GC-MS) indicated that elements and fractions distribution of bio-oil vary greatly from that of petroleum-based asphalt, and the small-molecule alcohols in bio-oil was a primary cause of bio-binder’s moisture damage resistance degradation. Moisture damage resistance validation of bin-binder at the mixture level showed that chemical modification incorporating one of the proposed chemical acids, phthalic anhydride with the dosage of 15% wt., can increase the moisture damage resistance index of residual Marshall stability (MS0) from 35.3% to 83.3%, and the tensile strength ratio (TSR) from 42.8% to 79.5%, which could meet pavement service specifications. Mechanism investigation of bio-oil’s chemical modification coupling gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) showed that the chemical modification proposed in this study improved bio-oil’s average molecular formulas from C14H35O18N0.1 to C32H56O6.3 N0.5, which was closer to that of base asphalt of C56H83O0.3 N0.5S0.2.