Dispersion of single wall carbon nanotube using air entraining agent and its application to portland cement paste

Abstract

There is a growing interest in research on application of carbon nanotube (CNT) for development of high-performance cementitious composites. However, most of the research works on cementitious composites were focused on utilization of multi-walled carbon nanotube (MWCNT) which is cheaper and more readily available in the market. Since single-walled carbon nanotube (SWCNT) has superior mechanical properties to MWCNT, it is necessary to investigate the effect of SWCNT on properties of cement paste. In this study, SWCNT was dispersed in water using commercial air entraining agent (AEA). Sodium deoxycholate (DOC) was also used as a dispersing agent for comparison purposes. Cement paste samples containing SWCNT solutions were prepared, and rheological behavior, mechanical strengths and microstructural observation were investigated. According to the results, the addition of SWCNT solutions decreased plastic viscosity, but increased yield stress of cement paste. It was also found that addition of SWCNT increased both compressive and flexural strength of cement paste regardless of the type of dispersing agent used. Although cement paste with SWCNT dispersed by AEA showed less mechanical strength than that dispersed by DOC, it is still possible to be used as a dispersing agent for SWCNT because of its higher mechanical strength than plain cement paste as well as better economic efficiency and readiness of AEA toward construction business.