Compatibility of carbon nanotubes in concrete with air entrainer and superplasticizer

Abstract

Multi-walled carbon nanotubes (MWCNTs) have great potential to improve performance of cementitious material in terms of mechanical, durability and electrical. This study quantitatively investigates the compatibility between MWCNTs, admixtures of superplasticizer and air entrainer (AE) in concrete materials, by performing experimental tests of surface tension, foam index and air content. Through applying various combination of admixtures and MWCNTs in concrete samples, the study finds that for concrete with MWCNTs, superplasticizer and air entrainer (AE), the surface tension, foam index, and air content could decrease up to 33%, 42%, 60%, respectively, and this significant change of air system can damage concrete freeze–thaw resistance. The significant decrease of air void content indicates the interaction between carbon nanotubes, superplasticizer and air entrainer. This interaction is further verified considering various levels of water/cement ratio or different brands of air entrainer. The study discovered the potential conflict during the application of nano materials and traditional admixtures and focused on much complicated concrete material.