On the effect of carbon nanotubes in Ultra-High Performance Fibers Reinforced Concrete

The addition of carbon nanotubes is an effective method to enhance mechanical properties and durability performance of structural concrete. Recently, experimental studies have investigated the behavior of Ultra-High erformance fibers reinforced Concrete (UHPFRC) mixtures including steel fibers and the carbon nanotubes duly dispersed within their matrix. The aim of this paper is to present the numerical results of a preliminary analysis on the effect of carbon nanofillers on the stressstrain behavior of the cementitious matrix, as well as on the bond interaction between the matrix and the steel fibers constituting UHPFRC. For this purpose, the meso-mechanical model developed by two of the authors for the study of the post-cracking response of fiber reinforced concrete, is here extended and applied for evaluating the effects of the addition of nanofiller on the cracking and the post-cracking response of UHPFRC specimens. In order to characterize the stress-strain relationships of the cementitious matrix and to back-calculate the bond-slip laws of steel fibers embedded within the latter, a comparison with the experimental results available in the literature has been also developed.