活化胶粉/纳米碳酸钙复合改性沥青性能影响及机理研究

Study on properties and mechanism of asphalt modified with active rubber powder/nano⁃calcium carbonate composites

目前日益增长的交通轴载量给沥青路面带来了更大的压力。本文选用不同活化程度的废旧胶粉(CR)和表面改性后的纳米碳酸钙(Nano⁃CaCO_(3))作为改性剂,制备活化胶粉/Nano⁃CaCO_(3)复合改性沥青样品,并通过针入度、软化点、延度的比较提出了3种最优的改性体系。在此基础上,通过动态剪切流变仪(DSR)研究改性沥青的高温性能。通过薄膜烘箱试验(TFOT)研究改性沥青的抗老化性能。通过离析试验研究改性沥青的贮存稳定性。通过荧光显微镜(FM)和傅里叶变换红外光谱(FTIR)观测改性沥青的微观形貌和官能团变化。结果表明,活化处理可以改善胶粉与沥青的相容性,提高改性沥青的贮存稳定性。3种最优改性体系的改性沥青具有良好的高低温性能、抗老化性能、施工和易性和贮存稳定性。对于活化胶粉和活化胶粉/Nano⁃CaCO_(3)复合改性沥青,改性过程中既发生物理反应,也发生化学反应。其中5#改性沥青为3种复合改性体系中综合性能最优的改性体系。

At present the increasing traffic axle load brings a greater pressure to asphalt pavement.In this study,the waste rubber powders with different activation degrees and the surface⁃modified nano⁃CaCO_(3)were employed as modifiers to prepare activated rubber powder/nano⁃CaCO_(3)composite⁃modified asphalts,and three optimal modification systems were proposed through comparing the penetration and softening point ductility of the modified asphalts.The high⁃temperature performance of the modified asphalts was investigated by DSR,their anti⁃aging performance was evaluated by a thin film oven test,their storage stability was assessed by a segregation test,and their morphology and functional groups were analyzed by fluorescence microscopy and Fourier⁃transform infrared spectroscopy.The results indicated that an activation treatment improved the compatibility between rubber powders and asphalt,thus enhancing the storage stability of the modified asphalts.The modified asphalts obtained from the three optimal modification systems exhibited good high⁃and low⁃temperature performance,anti⁃aging performance,workability,and storage stability.Both physical reaction and chemical reaction occurred in the modification of activated rubber powders and activated rubber powder/nano⁃CaCO_(3)composite⁃modified asphalts.Among the three optimal modification systems,the sample 5#exhibited the best comprehensive performance.