Durability characteristics and mechanical properties of multi-walled carbon nanotubes reinforced concrete, a case study: Caspian seawater curing condition

Abstract

Using multi-walled carbon nanotubes (MWCNTs) as an additive in a concrete mixture with an amount of 0.05 to 0.2% wt. of cement weight with a constant W/C ratio using local materials was investigated in this research. Specimens were cured in water and the Caspian Seawater curing conditions, and compressive strength tests were performed on samples up to 365 days of age. Also, flexural strength, water absorption after immersion, water permeability and porosity tests and, SEM studying were performed on specimens. Results showed that increasing the amount of MWCNTs up to 0.2% of cement weight improved the workability, compressive, and flexural strength of concrete mixtures. The addition of MWCNTs caused a mild improvement in concrete specimens’ strength which were cured in Caspian Seawater compared with control concrete. In the water absorption and water permeability tests, it was seen that a lower percentage of MWCNTs decreased the results, but more amount of MWCNTs may affect vice versa. In porosity studying, it was seen that more amount of MWCNTs may cause smaller pore sizes, however may increase the porosity and CNTs’ agglomeration in concrete.