骨料分布的均匀性对大流动性混凝土强度和耐久性的影响

Influence of Uniformity of the Distribution of Aggregate on Strength and Durability of High Fluidity Concrete

针对泵送混凝土因均匀性差而产生的不均匀收缩和易开裂等问题,提出了混凝土中骨料分布均匀性的测试和表征新方法,研究了大流动性混凝土流动性和振动时间对其骨料分布均匀性的关系、均匀性对混凝土力学性能和耐久性的影响。结果表明,混凝土拌合物的流动性和振捣效果对混凝土均匀性影响很大,混凝土中骨料分布的均匀性对混凝土抗折强度和抗压强度的偏差值影响较大,对其变形性能和耐久性的影响更大,骨料分布的均匀性越好,混凝土收缩率越低,抗塑性开裂性能和抗氯离子渗透性能越好。

Based on the non-uniform shrinkage and crack sensibility problems of pumping concrete caused by poor homogeneity,this paper proposes the new testing and characterization methods of concrete homogeneity and studies the relationship between high fluidity concrete homogeneity as well as vibration time and aggregate distribution homogeneity,it also studies the effects of concrete homogeneity on mechanical and durability performance.The results indicate that new mixed concrete fluidity and vibration time have great influences on concrete homogeneity,the aggregate distribution homogeneity in concrete has stronger effects on concrete rupture strength and compressive strength deviation,and has even much stronger influence on concrete deformation and durability performance.With better aggregate distribution homogeneity,concrete will has lower shrinkage rate,better plastic crack resistance and anti-permeability of chlorine ion.