Description
This paper deals with the preliminary results of an experimental investigation carried out at the Structural Engineering Testing Hall (STRENGTH) of the Department of Civil Engineering of the University of Salerno (Italy) on the mechanical and physical properties of self-sensing concrete (SSC) incorporating Industrial Grade Multi-Walled Carbon Nanotubes (MWCNTs). It has been recently demonstrated that the use of self-sensing material in the Civil engineering field may provide a cost-effective solution for the structural health monitoring (SHM) of reinforced concrete structures. One of the weak points of these smart composite materials is related to the difficulty of ensuring homogeneous dispersion of the functional filler in the matrix. Therefore, the preparation technique must be thoroughly investigated. On the other hand, there is no unified standard or specification for CNT dispersion, which limits the standardized use of CNT in building materials. The experimental investigation was performed at the STRENGTH LAB with a dual purpose: (i) to analyse the effects of nano-additives dispersion on the microstructure of the mixtures and (ii) to determine the influence of MWCNTs on their compressive behavior. A total of sixty samples were casted, considering (a) five concentrations of MWCNTs, ranging from 0% to 0.1% by weight of cement, each with an increment of 0.025%, (b) two different matrices, Portland cement (42.5R) and high-performance cement (Geolite Magma), and (c) two different surfactants, along with sonication, used for the dispersion of carbon nanotube in the water, Sodium Dodecyl Sulfate (SDS) and Polyvinylpyrrolidone (PVP). The main results, in terms of compressive strength after 28 days of curing and physical properties, obtained through a qualitative analysis of the surface morphology and microstructure of cementious composites, carried out using Scanning Electron Microscopy (SEM) images, are presented and discussed.
