硅烷改性磷石膏对沥青流变性能的影响

Effect of Silane-modified Phosphogypsum on the Rheological Properties of Asphalt

为了减轻磷石膏(PG)的大量堆积和填埋对环境造成的污染,本工作将经偶联剂处理后的磷石膏作为填料替代部分或全部矿粉,探究改性磷石膏对沥青胶浆的流变性能的影响。通过X射线衍射(XRD)和扫描电镜(SEM)分析了各样品的化学组成和微观形貌,然后制备沥青胶浆使用三大指标和布什旋转黏度研究其基础性能,最后通过多重应力蠕变(MSCR)试验、温度扫描和低温弯曲梁蠕变试验研究了样品的流变性能和疲劳性能。研究表明,经偶联剂改性后的磷石膏比表面积显著增大,表面粗糙多孔,更容易与沥青形成牢固的界面。在相同温度下,改性后的磷石膏沥青胶浆的高温性能进一步得到提升,在高、低应力下的弹性恢复能力优于磷石膏沥青胶浆。

In order to mitigate the environmental pollution caused by the massive accumulation of phosphogypsum(PG)and landfills,in this work,phosphogypsum treated with coupling agent was used as a filler to replace some or all of the mineral powders,and the effect of modified phosphogypsum on the rheological properties of asphalt mastic was investigated.The chemical composition and microscopic morphology of each sample were analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM),and then the asphalt mastic was prepared to test the conventional physical properties of each sample using the three major indexes and Bush s rotational viscosity,and finally the rheological and fatigue properties of the samples were investigated by the multiple stress creep test(MSCR),temperature scanning,and low-temperature bending beam creep test.It is shown that the specific surface area of phosphogypsum modified by coupling agent is greatly increased,the surface is rough and porous,and it is easier to form a strong interface with asphalt.At the same temperature,the high and low temperature performance of modified phosphogypsum asphalt mortar is improved,and the elastic recovery ability under high and low stress is better than that of phosphogypsum asphalt mortar.