微波胶粉比表面积对橡胶沥青流变性能的影响

通过考察不同微波辐射时间对胶粉活化处理并制备胶粉改性沥青的效果,研究微波辐射对胶粉表观特性与其改性沥青流变性能的影响。采用气体吸附仪、动态剪切流变仪分别测定胶粉活化前后的比表面积及改性沥青的流变性能,并将胶粉的比表面积与沥青流变性能进行关联。在此基础上,结合扫描电镜,从微观角度揭示活化胶粉对沥青流变性能的影响机理。结果表明:在测定时间内,微波辐射使得胶粉表面变得蓬松,孔隙增多,比表面积增长显著;一定时间范围内(60～120s)的微波辐射对胶粉改性沥青的高温抗车辙能力有显著影响;胶粉微波活化后其比表面积与改性沥青流变性能之间有很好的相关性,胶粉比表面积越大,其复数剪切模量越大,相位角越小,沥青的高温抗变形能力越好。

INFLUENCE OF SURFACE AREA OF MICROWAVE ACTIVATED CRUMB RUBBER ON RHEOLOGICAL PROPERTIES OF RUBBER ASPHALT

The effect of microwave activation on the apparent characteristics of crumb rubber and the rheological properties of asphalt modified by activated crumb rubber were investigated after different treatment times. The specific surface areas, rheological properties and their relations were studied by DSR and gas adsorption. The micro-mechanism of the rheological property changes of the asphalt modified by the activated rubber powder was investigated using SEM. The results showed that the surface of the rubber powder becomes fluffy and porous through the microwave treatment, leading a larger surface area; the microwave modification gives a significant influence on the high temperature resistance to rutting of the modified asphalt within a certain time range (60-120s). There is a good correlation between surface area of activated crumb powder and rheological properties of the modified asphalt. The larger surface area of the microwave treated crumb powder gives larger complex shear modulus, smaller phase angle, and better anti-distortion ability of asphalt.