基于不同搅拌方式下的水泥稳定碎石力学性能及细观结构研究

搅拌工艺对水泥稳定碎石的力学性能有较大影响。为了分析振动和非振动搅拌技术对水泥混凝土的力学性能和细观结构的影响,文章采用不同的搅拌工艺制备试样进行研究。采用CT试验分析了水泥砂浆在粗集料表面的分布情况;通过开展不同应力状态下的强度、模量和疲劳试验来揭示搅拌技术的影响;分别建立了强度随加载速率和模量随应力水平的变化规律,采用与加载速率相关的应力比修正的S-N疲劳方程来表征其疲劳性能。研究结果表明,振动搅拌技术制备的水泥稳定碎石试件的砂浆在骨料中分布更加均匀,密实型更高;在相同的试验条件下,振动搅拌制备的水泥稳定碎石试件的强度、模量和疲劳寿命均高于非振动搅拌成型的试件;振动搅拌制备的试件的强度和模量随加载速率的增长速率更高;与非振动搅拌制备的水泥稳定碎石试件相比,振动搅拌制备试件的疲劳寿命应力敏感性更加稳定。

Mechanical and Microstructure Analysis of Cement-Treated Aggregate by Different Mixing Technology

Mixing technology has a considerable influence on the mechanical performances of cement-treated aggregates.To analyze the effects of vibration and non-vibration mixing technology on the mechanical and microstructure of cement-treated aggregates,the specimens were prepared by different mixing technology.X-ray CT was employed to illustrate the distribution of cement mortar on aggregate.The strength,modulus,and fatigue tests under different stress states were performed to reveal the impacts of mixing technology.Then the variation patterns of strengths with loading rates and modulus with stress levels were established,respectively.Hereafter,the S-N fatigue equation,which modified with stress ratio related to loading rates,was used to describe the fatigue performance.The research results show that the mortar of the cement stabilized crushed stone specimen prepared by the vibration stirring technology is more uniformly distributed in the aggregate and the compactness is higher;under the same test conditions,the strength,modulus and fatigue life of the cement stabilized crushed stone specimens prepared by vibration stirring are higher than those of the non-vibration stirred molding specimens.Moreover,the growth rate of strength and modulus with loading for specimens prepared by vibration mixing is slightly larger.Compared with the cement-treated aggregate specimens prepared by nonvibration mixing,the fatigue life of cement-treated aggregate specimens prepared by vibration mixing has more stable stress sensitivity.