Performance and optimization of castor beans-based bio-asphalt and European rock-asphalt modified asphalt binder

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Department of Civil and Environmental Engineering


This study aims at investigating the composite modification effect of castor beans-based bio-asphalt and European rock asphalt on the properties of asphalt binders and optimizing the blending ratio of composite modified asphalt for specific properties by D-optimal mixture design (DMD). Penetration, softening point, ductility, rotary viscosity and dynamic shear rheometer (DSR) tests results revealed the addition of rock asphalt could compensate the adverse effect of bio-asphalt on the high-temperature performance of asphalt, and bio-asphalt could promote the swelling of rock asphalt by increasing complex modulus (G*) and decreased phase angle (δ). Fourier transform infrared spectroscopy (FTIR) results indicated that there no true chemical reaction occurred between bio-asphalt, rock asphalt and base asphalt. Additive bio-asphalt could effectively reduce the cost of asphalt binders. The optimal blending ratio of alternative AH-70 and AH-50 asphalt is obtained aiming at the requirement of penetration, softening point, ductility and viscosity by DMD: for AH-70, the optimal replacement ratio is 2.9% bio-asphalt, 16.7% rock asphalt, and 80.4% base asphalt; the optimal replacement ratio of AH-50 is 7.9% bio-asphalt, 6.3% rock asphalt, and 85.8% base asphalt. The application of DMD made the analysis of experimental data more intuitive and helped in composition optimization of bio-asphalt and rock-asphalt composite modified asphalt which meets specific properties, which provides a reference for the selection of other composite modified asphalt.

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Construction and Building Materials