Effect of Phosphogypsum Based Filler on the Performance of Asphalt Mortar and Mixture.

This study introduced phosphogypsum coupled with steel slag powder to prepare the phosphogypsum based filler (PF) for asphalt mixture. Penetration, penetration index, softening point, ductility, equivalent softening point, moisture stability of asphalt mortars with different steel slag powder content, filler-asphalt ratio, and PF content were studied. Mechanical properties of PF based asphalt mortar (P-AM) were then analyzed to determine the optimum steel slag content in PF.

Combined Use of Polyurethane Prepolymer and Aromatic Oil in Physicochemical Rejuvenation of Aged SBS Modified Bitumen for Performance Recovery.

The high-quality reutilization of waste styrene-butadiene-styrene copolymer (SBS) modified asphalt mixtures is a difficult issue in the field of highways today, and the main reason is that conventional rejuvenation technology fails to achieve the effective rejuvenation of aged SBS in binder, causing significant deterioration in the high-temperature performance of the rejuvenated mixture. In view of this, this study proposed a physicochemical rejuvenation process using a reactive single-component polyurethane (PU) prepolymer as the repairing substance for structural reconstruction and aromatic oil (AO) as a common rejuvenator used to supplement the lost light fractions of asphalt molecules in aged SBSmB, according to the characteristics of oxidative degradation products of SBS. The joint rejuvenation of aged SBS modified bitumen (aSBSmB) by PU and AO was investigated based on Fourier transform infrared Spectroscopy, Brookfield rotational viscosity, linear amplitude sweep, and dynamic shear rheometer tests.