New generation smart cementitious composites modified at nanoscale

In this thesis, nano materials were used singularly and binary in engineered cementitious composites (ECC) and self-healing and self-sensing functionalities were added to developed composites. Nano materials (nano silika [NS] and carbon nano tubes [CNT]) were incorporated into new generation smart cementitious composites with homogeneous and the most economical way without sacrificing the required performance. Control specimens that do not contain nano materials were also produced with the same amount of cubic, beam and cylindrical specimens in order to make comparison. Experiments of thesis include rapid chloride permeability tests, electrical resistivity tests, freeze/thaw tests, resonance frequency tests and loss of weight tests on the preloded and sound specimens. Mechanical properties of nano modified cementitious composites were undertaken with flexural and compression tests. Self-healing performances of each mixture that belongs to microcracks of specimens were analysed with video microscope tracking. Also, micro analysis were performed in order to investigate the micro structure of specimens having self-healing/sensing capabilities. Each mixture was characterized individually by conducting SEM/EDX, TGA and XRD tests. Although results indicate that CNT utilization was efficient on the self-healing and self-sensing properties, self-healing performance was at much higher level in the combination of NS and CNT. İntensity and amount of C-S-H and CaCO3 were higher especially in self-healing cracks thanks to the presence of NS and CNT. Compared to binary use of nano materials, only NS usage was inadequate in terms of precise self-healing performance. In addition to that, self-sensing performance of control and only NS bearing specimens were not sufficient especially at the lower level of loadings. Although only CNT bearing specimens showed the best results in terms of self-sensing performance, mixtures incorporating CNT and NS was also resulted in positively.