Effect of the dosage of MWCNT's on deterioration resistant of concrete subjected to combined freeze–thaw cycles and sulfate attack

Abstract

AbstractIn this study, the deterioration resistant of concrete with and without multi‐walled carbon nanotubes (MWCNTs) against combined freeze–thaw cycles and sulfate attack was studied, and concretes incorporating MWCNTs (i.e., 0.05, 0.10, and 0.15 wt%) as partial replacement of Portland cement were exposed to 5% sodium sulfate solution under freeze–thaw cycles. The performance, including compressive strength, relative dynamic elastic modulus, mass loss, microstructure, deterioration resistant coefficient of concretes were evaluated. Results show that when exposed to 5% sodium sulfate solution, MWCNTs could enhance the mechanical and durability properties of concrete subjected to combined freeze–thaw cycles and sulfate attack, regardless of the dosage of MWCNTs. The deterioration resistant of MWCNTs concrete was not increase with the increase dosage of MWCNTs. And the best resistance performance was obtained in concrete containing lower dosage of MWCNTs. In addition, MWCNTs could promote formation of hydration and corrosion products, and delay deterioration of concrete was demonstrated by SEM and thermogravimetric analysis.