الفهرس 
Corrosion of steel reinforcement
Experimental studyOnly 14 pages are availabe for public view
 |  | from | 139 |  |  |
| | | from | 139 | | |
Abstract
Steel corrosion is known to be a very common kind of deterioration of reinforced concrete which affects the integrity of any concrete structures and may cause human losses. All issues related to Corrosion process like its mechanisms, causes, and consequences should be well-understood in order to avoid spending a lot of money, time, and effort in repair works to restore the integrity of any concrete building suffers from corrosion issues.
Corrosion of reinforcing steel occurs due to carbonation process and/or free chloride ions. In this research work we will focus on chloride-induced corrosion. Chlorides in concrete can exist as free ions which cause steel corrosion or as bound chlorides that almost have no risk of corrosion. It is beneficial to bind free chloride ions to reduce the corrosion probability of the reinforcement embedded in the concrete.
The chloride binding process can be physical; by absorption of chloride ions on the surface of the hydration process, or chemical (which is more stable) by interaction with alumina phases to produce an insoluble salt called Friedel’s salt. The binding capacity of the concrete varies and depends on the chemical composition of its cementitious system.
This thesis investigates the chloride binding capacity of different kinds of SCMs that used as a partial replacement of CEM I. It is confirmed by other researches that those materials have a higher binding capacity than CEM I, also, they showed a higher resistance against corrosion. Different properties of concrete after chloride binding are assessed through carrying out the following tests: half cell potential, accelerated corrosion test, compressive strength, pull-out test, rapid chloride penetration test, sorptivity test, measuring pH value of concrete, and XRD. The results showed that utilizing the SCMs in concrete can enhance the chloride binding capacity, especially those materials that have high quantities of aluminate and calcium in their chemical composition like ground granulated blast furnace slag (GGBFS). Also, all mixes made with SCMs had a better behavior against corrosion than control mixes that were made using CEM I only.
Based on such results, the limit of the chloride content in the different codes should be revised regarding the binding capacity according to the type and quantity of the cementitious materials used.