低液限红黏土对混凝土和易性及力学性能的影响

为了探究低液限红黏土对混凝土和易性及力学性能的影响,采用低液限红黏土、碎石、机制砂制备塑性混凝土,探讨黏土掺量与水灰比对混凝土和易性、抗压强度、劈裂强度、弹性模量的影响。结果表明:低液限红黏土能改善混凝土的流动性、黏聚性和保水性,1 h后的坍落度仍能保持在173 mm以上,同时黏土能大幅度地延迟混凝土的初凝和终凝时间和显著降低混凝土的表观密度。黏土等质量替代水泥后,随着养护龄期的延长,混凝土抗压强度、劈裂强度呈对数关系增加。相对而言,黏土掺量对混凝土抗压强度的影响比水灰比要大。黏土掺量越大,混凝土的弹性模量越小,且可采用混凝土抗压强度的线性关系来预测。

Effect of low liquid limit red clay on workability and mechanical properties of concrete

Plastic concrete was prepared by low liquid limit red clay, sand and gravel to discuss the effect of low liquid limit red clay on concrete workability and mechanical properties. The effect of low liquid limit red clay content and water cement ratio on plastic concrete workability, compressive strength, splitting strength, modulus of elasticity was discussed in the paper. The results showed that: low liquid limit red clay can improve liquidity, adhesiveness and water retention of the concrete, after 1 hour slump remained above 173 mm, and red clay can significantly delay initial setting and final setting time of concrete and significantly reduce apparent density of concrete. Compressive strength, splitting strength of concrete increases with logarithmic relationship with extension of curing age when clay replaces cement. Relatively speaking, the effect of clay content on concrete compressive strength was higher than water cement ratio. The larger the clay content is, the smaller the elastic modulus of the concrete are, which can be predicted by the linear relationship between compressive strength and elastic modulus of concrete.