Study of high and low-temperature properties of phosphogypsum-modified asphalt
The high and low-temperature performance of phosphogypsum-modified asphalt was examined to assess the potential of phosphogypsum as a modifier in asphalt.Various concentrations of phosphogypsum are added to 70#base asphalt to form phosphogypsum-modified asphalt.The high-temperature rheological properties of phosphogypsum-modified asphalt were tested by temperature sweep,frequency sweep,and multiple stress creep and recovery(MSCR)tests of a dynamic shear rheometer.Rheological master curves were established based on the Sigmoidal equation.The low-temperature crack resistance of phosphogyp-sum-modified asphalt was evaluated by bending beam rheometer.The results show that with the addition of phosphogypsum,the complex shear modulus(G∗)of phosphogypsum-modified asphalt increases and is higher than 70#base asphalt while the phase angle(δ)changes slightly,and the Shenoy rutting parame-ter[G∗/(1-1/sinδtanδ)]increases significantly.The addition of phosphogypsum can improve the re-covery rate at 0.1 kPa and 3.2 kPa,and reduce the unrecoverable compliance at 0.1 kPa and 3.2 kPa.The addition of phosphogypsum enhances the high-temperature performance of the based asphalt while slightly decreasing the low-temperature cracking resistance of the asphalt,but it does not affect the design temperature in the low-temperature grading of the phosphogypsum.
NETL
NSTL
万方数据
