Abstract

This paper investigated the efficiency of concrete reinforced with multi-walled carbon nanotubes (MWCNTs) specimens in terms of fresh concrete slump, compressive strength, static and dynamic moduli of elasticity, the drying shrinkage strain, and microstructure. In addition, the particle sizes distribution of MWCNTs dispersions in water was investigated by the dynamic light scattering (DLS) test. The dispersion sonicated with an ultrasonic probe had a smaller distribution range with a higher rate in smaller particle sizes compared with the dispersion sonicated with an ultrasonic bath. By incorporation of MWCNTs with an amount of 0.05–0.2% of cement weight, the fresh concrete workability, and the 365 day-age drying shrinkage strain are reduced up to 20% and 24%, respectively; also, the compressive strength, the static modulus of elasticity, and the dynamic modulus of elasticity increased up to 35.4%, 8.9%, and 5%, respectively. The SEM studies showed the bridging behavior of MWCNTs in the cement paste matrix at the nanoscale, and map analysis showed the distribution and the aggregation of MWCNTs in some parts of the concrete mixture.

摘要

本文从新拌混凝土坍落度、抗压强度、静态和动态弹性模量、干燥收缩应变和微观结构等方面研究了用多壁碳纳米管 (MWCNT) 试样增强的混凝土的效率。此外，通过动态光散射（DLS）测试研究了多壁碳纳米管在水中分散体的粒径分布。与用超声浴超声处理的分散体相比，用超声探头超声处理的分散体具有更小的分布范围，并且在更小的粒径中具有更高的速率。通过掺入占水泥重量 0.05-0.2% 的多壁碳纳米管，新拌混凝土的和易性和 365 天干缩应变分别降低了 20% 和 24%；还有，抗压强度，静态弹性模量，动态弹性模量分别提高了 35.4%、8.9% 和 5%。SEM 研究显示了多壁碳纳米管在纳米级水泥浆基体中的桥联行为，图谱分析显示了多壁碳纳米管在混凝土混合物某些部分的分布和聚集。