الفهرس 
CHAPTER (1) (1) IntroductionOnly 14 pages are availabe for public view
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Abstract
Reinforced concrete structures are overwhelmingly exposed to a various condition, these conditions may lead to deterioration in structural behaviour and reduction in structure service life that, governs the structural performance of the building. For example, reinforcing steel rebars corrosion is one of the most popular forms of deterioration for ordinary Portland cement base concretes. Although, Portland cement concrete production is associated with significant environmental impacts, as massive consumption of natural resources and responsibility for almost 6–7% of all the greenhouse gasses emitted worldwide. However, Alkali Activated Materials (AAMs) gives emissions of carbon dioxide up to nine times less and represents many characteristics of traditional concretes regarding mechanical performance and durability [1]& [2], despite their different chemical composition and reaction mechanisms, AAMs is relatively young material regarding available data crucial for durability and predicting the service life of reinforced AAMs such as chloride ingress properties, chloride diffusion coefficient or corrosion rate of reinforcing steels is limited. Generally, the life cycle of concrete structures with corroded and uncoated reinforcing steel rebars can be expressed into consequent three stages:
Stage I: inspects the healthy status of the RC structures, starting from the construction accomplishment time to the corrosion initiation, which is controlled by diffusion resistance of chloride ions through the exposure surface of the concrete, or binding ability for free chlorides contaminated into the mix design.
Stage II: inspects the structure’s damage status starting from the corrosion initiation to the end of serviceability (in correspondence to the code-specified critical limits for crack width, deflection, or delamination, etc.). This Stage is controlled by the environmental effects on the reinforcement rebars corrosion rate corelated to material characteristics such as permeability and thickness.
Stage III: inspects the structural safety status starting from the serviceability limits overcoming to the ultimate failure (expressed in strength losses flexural or shear, etc.) due to reinforcing rebars’ cross-sectional reduction. Stages after when rebar corroded is primarily controlled by environmental factors [3].
In this research we focused on stage I for three alkali activated materials and correlated their behaviour to the well-known governing rules for OPC. Initial experimental program was made for samples in the normal curing condition (ambient temperature) and under different curing regimes using three different based geopolymer binders (Fly Ash, Metakaolin and Slag) to asses free chloride binding capability for each binder, especially binders rich in Aluminium (AL) and Silicon (Si) oxides, through XRD test and determination of free chloride ions tests, also, mechanical properties assessment through several tests carried out such as SEM, compressive strength and so on. Two main binders were chosen to complete testing program and MK binder was excluded. Then suffix testing program were executed to estimate diffusion resistivity such as sorpitivity test, chloride penetration test, etc. Results distinguished between OPC behaviour and AAMs in binding chloride ions which is not dependant on chemical composition rich with AL and Si oxides but depends on each composition reactivity in the binder whereas chloride ions chemically binded in different phases. Research highlighted the rule of CaO and sodium compounds in gaining strength, furthermore, increasing in strength was strong evidence for higher chemical resistivity. On average results alkali activated materials-based concretes had poor microstructure caused chloride permeability propagation. Additional further studies are recommended for obtaining optimal microstructural mixes.