Static and dynamic moduli of elasticity and drying shrinkage behavior of concrete containing multi-walled carbon nanotubes

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.