Preparation Of Calcium Sulphate Whisker And Its Application Study In The Paving Asphalt

Calcium sulfate whisker(CSW) which capability is better and the morphology is even and controllable was prepared by hydrothermal synthesis method using gypsum as raw material and magnesium chloride as crystal promoter respectively in this paper. The effects of reaction temperature and time, slurry concentration, mol ratio of Ca to Mg, granularity of ity lity raw material and pH value of solution etc on the preparation and morphology of CSW were investigated in detail. The morphology and aspect ratios of CSW product were observed by the Polarization Microscope. The effects of reaction factors on the morphology and phase constitution of CSW were studied by Scanning Electron Micrograph(SEM) and X-ray diffraction(XRD) respectively in detail, moreover, the growth mechanism under hydrothermal conditions of CSW was analyzed. The heat stability and surface capability of calcium sulfate whisker were observed by Thermo Gravimetry(TG)and Fourie Transform Infrared ray(FT-IR) respectively, which offered theory bases for its surface modifing and application study.According to its surface capability characteristic, the calcium sulfate whisker was pretreated with silane coupling agent, titanate coupling agent and organic acid etc, which surface modification effect was evaluated by Fourie Transform Infrared ray(FT-IR).The optimized treatment craft was putted forward innovatively to avoid the break off of CSW during modification in this paper. At the same time, the interface action mechanism between CSW and modifier was explained in theory.The application research of CSW in paving asphalt was carried on. The change rules of soft point, penetration and ductility of modified asphalt with the change of filler's dosage, modifying craft factors and capability of alkylic asphalt were analyzed, moreover, the influence mechanism was expatiated. The mechanism of CSW modifying paving asphalt was analyzed and discussed based on the mechanism of fiber treating asphalt, solubility theory, colloid and interface theory, etc.