الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
Abstract
The capability of concrete to sustain the environmental circumstances without serious deterioration makes it an ideal material for building structure when concretes are exposed to the outdoors. The concept of using micro admixtures to reinforce cementitious matrix became a well-known. The hydration process generates crystal water and formless crystals ranged in nanometer to micrometer scale, in addition to the strength of this products are impacted by properties in micro and nano scale on the nanoscale. Pozzolans material such as Nano clay (NC) have filling effect leading to denser matrix, react with calcium hydroxide and form addition calcium-silicate-hydrate gel (C-S-H), moreover act as a “nuclei” of the hydration process and accelerate it. Using discrete fibers like Carbon Nanotubes (CNTs) helps the distribution of stress to become more uniformly within matrix. It was found, CNTs exhibit lower shrinkage, resist crack propagation by the bridging effect, act as “nuclei” of the hydration process, have packing effect leads to decrements in voids, furthermore the connection effect helps in enhancing transfer of load under stress. Recently, the ultra-sonication and homogenizing process became the common physical method to adopt the dispersion of nanomaterials, thus helps in preventing agglomeration and creating weak zones inside cementitious matrix.
This research thesis exhibits the outputs of an experimental investigation on the coupled influence of CNTs with addition NC on the fresh and hardened concrete properties, and then hybrid effect on the concrete durability subjected to corrosive environments, in addition, the bond strength. The results out of research detected the optimum ratio (5%) of NC subjected to the higher compressive strength value firstly, then detected the qualified percentages of the hybrid mixing subjected to the mechanical properties and durability of concrete subjected to corrosion environmental. The air content, sorptivity, water permeability and chloride penetration increased with all dosages CNTs. While the tensile strength, flexural strength, bond strength, corrosive bond strength enhanced with all studied dosages of CNTs (0.01%, 0.02%).The SEM observations found that, the major effect of CNT in the filling effect, bridging effect and nucleation as sub-centroplasm for C-S-H gel while the NC has pozzolanic reaction and filling effect.