不同沥青混合料的拌和黏度及和易性

Mixing Viscosity and Workability of Different Bituminous Mixtures

摘要: 为了研究不同沥青混合料的拌和黏度及和易性，试验选取了70^#基质沥青、SBS改性沥青、橡胶沥青和两种温拌沥青等5种不同种类的沥青，测试了布氏黏度，制备了AC-13C型沥青混合料，利用变速拌和功率测试试验装置，在不同拌和温度(140˚C~180˚C)和不同拌和速率(20~50 r∙min⁻¹)下，对5种沥青混合料进行了变速拌和试验，通过分析“拌和功率－拌和速率”流变图，研究了混合料的拌和黏度及和易性指数。结果表明：沥青混合料的拌和流变特性服从线性黏塑性的宾汉模型；混合料的拌和黏度和沥青的黏度之间具有良好的正相关性；拌和黏度对混合料的和易性有重大影响，相同拌和温度时，SBS改性和橡胶沥青混合料的和易性较差，温拌沥青混合料的和易性较好；随着拌和温度的升高，拌和和易性有明显改善。

Abstract: In order to research the mixing viscosity and the workability of different mixtures, five different bitumen such as 70^# matrix bitumen, SBS modified bitumen, rubber bitumen and two kinds of warm bitumen were selected to prepare five asphalt mixtures in type of AC-13C, and the Brookfield viscosities were tested for each bitumen. Using an experimental device of mixing power measurement at different velocities, the variable mixing velocity experiment was carried out for the five different asphalt mixtures at different mixing temperatures (140˚C - 180˚C) and mixing velocities (20 - 50 r∙min⁻¹). By analyzing the rheogram of mixing power and mixing velocity, the mixing viscosity and the workability index of the mixtures were studied. The result shows that the mixing rheological characteristic of mixture obeys the linear visco-plastic Bingham model; the mixing viscosity of mixtures has a positive correlation with the bitumen viscosity; the mixing vis-cosity influences greatly the workability of mixture, and at the same temperature, compared to 70^# matrix asphalt mixture, the SBS modified and rubber asphalt mixture present a madder workability, and the warm asphalt mixture is observably better; the workability indexes increase significantly by increasing the mixing temperature.