电气石负离子粉改性沥青性能及其改性机理

Properties and modify mechanism of tourmaline anionic powder modified asphalt

为探究电气石负离子粉改性沥青的路用性能,采用高速剪切法制备不同电气石负离子粉掺量的改性沥青,并通过常规物理性能试验、多应力蠕变恢复试验(MSCR)、低温弯曲梁流变试验(BBR)及布洛克菲尔德黏度试验对电气石负离子粉改性沥青的高温性能、低温性能及黏温特性进行深入分析.借助XRD射线衍射仪、光学显微镜、傅里叶红外光谱仪(FT-IR)及差示扫描量热仪(DSC)分别对改性沥青的微观形貌、化学组成及热物性进行表征与分析,从微观角度对电气石负离子粉的改性机理进行分析.结果表明:凭借其优良的热电性及压电性电气石负离子粉能够显著改善沥青的高低温性能及黏温特性,但掺量过高时,改性沥青的低温抗裂性能的改善效果有所下降;电气石负离子粉能够均匀分散于沥青基体中,且形成一种能够有效改善沥青技术性能的类似于海绵状网络的三维结构;相较于基质沥青,改性沥青的玻璃化转变温度Tg与吸热量ΔH均得到了改善,改性沥青呈现出更优的热稳定性;电气石负离子粉与基质沥青之间化学兼容性良好,电气石负离子粉对基质沥青以物理改性为主.

In order to investigate the pavement properties of tourmaline anionic powder modified asphalt,modified asphalt with different contents of tourmaline anionic powder were prepared by a high speed shear method,then,the high and low-temperature performance,viscosity-temperature property were studied by means of the conventional physical performance test,multiple stress creep recovery test(MSCR),bending beam rheometry(BBR)and Brookfield viscosimeter test,respectively.The microstructure,chemical composition and thermal properties of the modified asphalt were characterized and analyzed by means of X-ray powder diffraction(XRD),Fourier infrared spectrometer(FT-IR),optical microscope and differential scanning calorimetry(DSC)so as to investigate the modification mechanism of tourmaline anionic powder from a microscopic perspective.The results show that tourmaline anionic powder can significantly improve the high and low-temperature performance and viscosity-temperature properties of asphalt by virtue of its excellent thermoelectric and piezoelectric properties.Moreover,tourmaline anionic powder can be dispersed uniformly in the base asphalt and form a kind of cavernous network structure,which can effectively improve the technical performance of asphalt.Compared with base asphalt,both the Tg andΔH are sigificantly improved,and the modified asphalt exhibit a better thermal stability.There is only physical interaction between tourmaline anionic powder and asphalt.