الفهرس 
Scope of WorkOnly 14 pages are availabe for public view
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Abstract
Concrete is one of the most significant and common material in the
construction field because of its strength, economy, and availability.
However, it is vulnerable to deterioration that directly based on its durability.
Different concretes demand uneven degrees of durability based on the
exposure environments and also the required properties. Many researchers
have conducted deep studies on how to enhance the concrete durability and
reported that using pozzolanic materials proved to be effective in promoting
its durability due to their pozzolanic reaction which reacts with excess
calcium hydroxide (CH) forming extra calcium silicate hydrate (C-S-H) gel
which enhances the interfacial transition zone (ITZ) among aggregates and
cement blends resulting in promoting concrete strengths and its durability.
Since the main hydration product of cement-based materials is C-S-H gel
which is a nanostructured material, in addition, a number of widely spread
nano-sized pores exist in the cement matrices, that make concrete a
microstructure material influenced with its nano-properties. The addition of
nano-materials to concrete enhance its properties due to the presence of the
extremely small size particles which fill the existing nano pores within matrix
resulting in a well compacted, dense and uniformly restructured matrix.
However, the common problem of nano-materials is that particles have a
strong tendency to assemble around each other and form agglomerations as a
iv
result of van der Waals force. These agglomerations affect negatively the
performance of concrete matrix .
This research thesis presents the results of an experimental investigating on
the effect of nano-clay (NC) dispersion with using various percentages of NC
up to 10% on the fresh and hardened concrete properties, and then the effect
of adding the well dispersed NC on the concrete durability subjected to
corrosive environments, in addition, the bond strength. The results out of
research detected a number of important conclusions at the dispersion level
for all replacement percentages, where the sonication of NC particles
significantly enhanced concrete properties when compared to those of asreceived
NC. The enhancements of compressive strength, splitting tensile
strength, flexural strength, bond strength(rebar-12mm), and bond
strength(rebar-16mm) of concrete incorporating 7.5% sonicated NC were
28.25%, 16.67%, 17.4%, 26.9%, and 12.75% respectively when compared to
the as-received NC. The concrete mixes incorporated NC particles were
impermeable. The enhancement of water penetration depth, chloride
resistance, and abrasion resistance of concrete incorporating 7.5% sonicated
NC were 90%, 72.91%, and 24.32% when compared to the control mix, while
the corrosion rates were classified as negligible and the critical time reached
79 years for both 12mm and 16mm rebar by incorporating 7.5% NC rather
than 19.5 years for the control mix. The bond strengths after being subjected
to corrosive environments were equivalent 82.98% and 85.65% of their values
before subjected to corrosive environment for 12mm and 16mm respectively.
Key Words: Nano Clay, Dispersion, Bond Strength, Abrasion Resistance,
Durability, Corrosive Environments.