级配类型对沥青混合料拌和流动性及和易性影响研究

Effect of Gradation on Mixing Flowability and Workability of Asphalt Mixtures

为了保证沥青路面的铺筑质量,沥青混合料应具有良好的流动性及和易性。针对级配类型对混合料拌和流动性及和易性的影响,制备了AC-13、AC-20、ATB-25、SMA-13和OGFC-135种沥青混合料,利用自主开发的变速拌和试验装置,在不同工况下进行变速拌和试验,并绘制“拌和功率-拌和速率”流变图,分析拌和流动模型及流动参数,定义了和易性指数。结果表明:沥青混合料的拌和功率与拌和速率具有良好的线性关系,拌和流动特性服从宾汉流变模型。从理论上引入了拌和塑限和拌和黏度两个流动参数;这两个拌和流动参数决定了沥青混合料的拌和和易性,数值越大,和易性越差;集料级配类型对沥青混合料的拌和塑限影响较大,但对拌和黏度影响较小,拌和温度对沥青混合料的拌和塑限几乎没有影响,但对拌和黏度影响显著。

In order to ensure the paving quality of asphalt pavement,the asphalt mixture shall have good fluidity and workability.Aiming at the influence of gradation type on mixing fluidity and workability of mixture,the paper prepared five kinds of asphalt mixtures,AC-13,AC-20,ATB-25,SMA-13and OGFC-13.Using the self-developed variable-speed mixing test device,the variable-speed mixing test was carried out under different working conditions,and the"mixing power-mixing rate"rheological diagram was drawn,the mixing flow model and flow parameters were analyzed,and the workability index was defined.The results show that the mixing power of asphalt mixture has a good linear relationship with the mixing rate,and the mixing flow characteristics follow the Bingham rheological model.Two flow parameters,mixing plastic limit and mixing viscosity,are introduced theoretically.These two mixing flow parameters determine the mixing workability of asphalt mixture.The greater the value,the worse the workability.The aggregate grading type has a great impact on the mixing plastic limit of asphalt mixture,but has a small impact on the mixing viscosity.The mixing temperature has little impact on the mixing plastic limit of asphalt mixture,but has a significant impact on the mixing viscosity.