搅拌方式对水泥稳定碎石混合料抗压强度的影响

为了提高水泥稳定碎石混合料的搅拌均匀性，改善抗压强度，采用正交试验的方法，对水泥质量比（用量，下文同）为4%的悬浮密实型混合料，通过分析振动搅拌条件下不同位置混合料的7 d无侧限抗压强度及其变异系数，确定搅拌时间、湿拌时间、振动频率和搅拌速度的合理取值与匹配，并在此基础上对3%、4%和5%水泥用量的悬浮密实型和骨架密实型混合料，开展振动搅拌与普通搅拌的对比试验，分析振动搅拌对水泥稳定碎石混合料抗压强度的影响。结果表明：在振动搅拌条件下，搅拌时间对混合料抗压强度的影响最大，振动频率和搅拌速度次之，湿拌时间的影响最小，并且随着各搅拌参数取值的增大，抗压强度增加且变异系数降低；在选用合理搅拌参数的基础上，振动搅拌能够显著提升混合料的强度指标，但随着水泥用量增加，振动搅拌混合料的强度提高率降低；与普通强制搅拌相比，振动搅拌悬浮密实型混合料的强度平均提高20.7%，骨架密实型混合料的强度平均提高16.1%，强度变异系数降低约40%；在相同的水泥用量下，振动搅拌和普通强制搅拌的骨架密实型混合料强度都明显高于悬浮密实型，但振动搅拌对悬浮密实型混合料更为敏感，强度提升幅度更大。

Influence of Mixing Methods on Performance of Compressive Strength for Cement Stabilized Macadam Mixture

To improve mixing uniformity of cement stabilized macadam and its compressive strength, for suspended dense mixture with 4% cement content, 7 d unconfined compressive strength and its variation coefficient from different locations in the same batch under vibratory mixing (VM) conditions were analyzed to get the reasonable mixing time, wet-mixing time, vibration frequency and mixing speed by orthogonal test method. On this bases, the comparative test of VM and conventional compulsory mixing (CM) was conducted on unconfined compressive strength of suspended dense mixture and skeleton dense mixture with the cement content of 3%, 4%, 5%, respectively. The influence of VM on compressive strength of cement stabilized macadam was analyzed. The results show that mixing parameters affect the compressive strength under vibratory condition. The most influence factor is mixing time, followed by vibration frequency and mixing speed, whilst the least effect factor is wet-mixing time. The compressive strength of the mixture increases, and its variation coefficient decreases with the increase of the mixing parameters. VM can significantly improve the strength of the mixture based on the reasonable parameters, but the strength gets less promotion by VM with the increase of cement content. The compressive strength of suspended dense mixture and skeleton dense mixture under vibratory conditions increase by 20.7% and 16.1% respectively, on average. And the variation coefficient decreases by 40%, compared with CM. The compressive strength of skeleton dense mixture under VM and CM is significantly higher than that of suspended dense mixture with the same amount of cement, but VM is more sensitive to the suspended dense type with greater promotion.