橡胶-硅藻精土复合改性沥青的制备及机理

Preparation and Performance Research of Rubber-Diatomite Composite Modified Asphalt

为了改善沥青的高温性能,采用橡胶和硅藻精土制备多种掺量的复合改性沥青。利用针入度、软化点、延度、旋转黏度试验,对不同改性沥青性能进行表征,通过曲面响应法得出改性剂最佳掺量比例,并对比橡胶沥青、橡胶-SBS复合改性沥青进行改性效果评估。采用旋转薄膜烘箱老化试验、热重分析法、差示扫描热量法、红外光谱扫描试验、扫描电镜试验研究了橡胶-硅藻精土复合改性沥青的老化性能、高温性能、微观结构和反应机理。结果表明,22%橡胶和4%硅藻精土的复合改性沥青综合性能最好。与橡胶沥青、橡胶-SBS复合改性沥青相比,橡胶-硅藻精土复合改性沥青表现出了更好的高温稳定性;橡胶粉、硅藻精土与基质沥青之间主要存在物理共混,沥青与两者形成了相互固定的均匀稳定的整体。

In order to improve the high-temperature performance of asphalt,a variety of composite modified asphalts with different proportions of rubber and diatomite were prepared.The performance of various modified asphalt formulations was assessed through tests measuring penetration,softening point,ductility,and rotational viscosity.Subsequently,the optimal modifier blending ratios were determined using response surface methodology.The modification effects were evaluated by comparing them to rubber asphalt and rubber-SBS composite modified asphalt.The aging properties,high-temperature performance,microstructure,and reaction mechanisms of the rubber-diatomaceous earth composite modified asphalt were investigated through rotational thin-film oven aging tests,thermal gravimetric analysis,differential scanning calorimetry,Fourier-transform infrared spectroscopy analysis,and scanning electron microscopy analysis.The results indicate that the composite modified asphalt with 22%rubber and 4%diatomite exhibits the best overall performance.Compared to rubber asphalt and rubber-SBS composite modified asphalt,the rubber-diatomite composite modified asphalt demonstrates superior high-temperature stability.There is mainly physical blending between rubber powder,diatomite,and matrix asphalt.Asphalt and the two form a uniform and stable whole that is fixed to each other.