الفهرس 
CHAPTER (1) INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 183 |  |  |
| | | from | 183 | | |
Abstract
Steel rebar corrosion is one of the main factors that cause concrete deterioration. Many studies were carried out to protect steel rebar against corrosion using different techniques. Only three protection techniques were addressed in this research 1) steel protective coating, 2) impressed current, 3) the sacrificed anode. The common practice in Egypt is to use the steel protective coating for small projects with light to medium aggressive environments. On other hand, the sacrificed anode and impressed current are usually used in medium to large projects in highly aggressive environments. The aim of this research is to compare both efficiency and cost of the three considered protection techniques in the light of the current market conditions in Egypt. In order to achieve that goal, an experimental program with two phases was carried out. The first phase aimed to study the rebars mass loss as efficiency indicator of each technique using two lollypop samples for each alternative. Two steel coating products commonly used in Egyptian market were tested besides three types of sacrificed anodes (Mg, AL & Zn) and finally two intensities of impressed current in addition to control samples. The results of the first phase showed that the protection efficiencies of the three considered techniques are about 100%, 80% and 55% for impressed current, steel coating and the sacrificed anode respectively. Accordingly, the second phase considered only the best steel coating product and the best impressed current intensity. The second phase aimed to measure the gain in structural capacity comparing with control sample as another indicator for protection efficiency using two concrete simple beams for each alternative besides two control beams. All beams were (100x100x1500mm) and they were pre-loaded up to normal working stress level during corrosion test. All samples in the two phases were tested using accelerated corrosion technique. The results of the second phase assured that impressed current is more effective than steel coating technique. Cost wise, the expense of each protection technique was calculated for a building in an aggressive environment for five years as a percentage of the total cost of the building. The results indicated that the cost percentages are 16%, 50% and 9% for impressed current, the sacrificed anode and steel coating respectively.