Effects of Carbon Nanotubes on the Properties of Lightweight Concrete Prepared With Expanded Glass and Hydrophobic Silica Aerogel

This study aimed to study the effect of carbon nanotubes on the properties of expanded glass and silica aerogel based lightweight aggregate concrete. CNTs were dispersed in the polycarboxylate superplasticizer added water by ultrasonication energy for 3 minutes. Combinations of expanded glass (55%) and hydrophobic silica aerogel particles (45%) were used as lightweight aggregates. Study results show that the incorporation of MWCNTs significantly influences the mechanical and microstructural performance of aerogel based lightweight concrete. Almost 41% improvement in compressive strength was gained by the addition of carbon nanotubes. SEM image of lightweight concrete shows CNTs were almost dispersed homogeneously within the concrete structure. SEM image of the composite also shows the presence of the C-S-H structure surrounding the CNTs, that confirms the cites of nanotubes for higher growth of C-S-H. Besides, agglomeration of CNTs and the presence of Ettringites observed in the transition zone between the silica aerogel and cementitious materials. Moreover, flowability, water absorption, microscopy, XRD, and semi-adiabatic calorimetry results were analyzed in this study.