RST高黏改性沥青感温性及贮存稳定性评价

Evaluation of temperature sensitivity and storage stability of RST high viscosity modified asphalt

采用RST改性剂制备高黏改性沥青,RST掺量为7%,9%,11%,13%,15%及17%,探究RST掺量对高黏改性沥青感温性及贮存稳定性的影响。首先,测定并计算RST高黏改性沥青的针入度指数(PI)、针入度黏度指数(PVN)及黏温指数(VTS),就不同环境温度下感温性进行评价;其次,采用离析管试验法测试(163±5)℃储存48 h后软化点差,就贮存稳定性进行评价;最后,通过荧光显微镜分析改性机理。结果表明,中温及中高温环境下,RST高黏改性沥青的感温性随改性剂掺量增加而改善;高温环境下,随RST掺量增加高黏改性沥青感温性呈先增大后减小。掺量不超过15%时,RST可吸收沥青中轻质组分并形成稳定的网状结构,提高沥青贮存稳定性;掺量超过15%时,RST在沥青中形成条状结构且发生离析现象,贮存稳定性不佳。

High viscosity modified asphalt was prepared with RST(Road Science Technology)modifier.The content of RST was 7%,9%,11%,13%,15%and 17%.The effect of RST content on the temperature sensitivity and storage stability of high viscosity modified asphalt was studied.Firstly,the penetration index(PI),penetration viscosity index(PVN)and viscosity temperature index(VTS)of RST high viscosity modified asphalt were measured and calculated to evaluate the temperature sensitivity at different ambient temperatures;secondly,the softening point difference after storage at(163±5)℃for 48 h was measured by the separation tube test method to evaluate the storage stability;finally,the modification mechanism was analyzed by fluorescence microscope.The results show that the temperature sensitivity of RST high viscosity modified asphalt is improved with the increase of modifier content under medium temperature and medium high temperature environment;in high temperature environment,the temperature sensitivity of high viscosity modified asphalt increases first and then decreases with the increase of RST content.When the content is less than 15%,RST can absorb the light components in asphalt and form a stable network structure to improve the storage stability of asphalt;when the content exceeds 15%,RST forms strip structure in asphalt and segregation occurs,resulting in poor storage stability.