Author : Shimaa Youssef Mohamed
Degree : M.Eng. Structural
Title:
Corrosion Inhibitors
in Concrete
Abstract:
Chapter one contains general
introduction of corrosion and its significant deterioration on the reinforced
concrete structures, its high cost of repairs, and corrosion protection systems
to mitigate the corrosion problems.
Chapter two gives some definitions of
corrosion, mechanism of corrosion, reasons of corrosion, some methods of
detecting and monitoring corrosion, and some methods of corrosion prevention.
This chapter gives definition of corrosion inhibitor, classification of
inhibitor, advantages of corrosion inhibitors, mechanism of inhibitor, effect
of corrosion inhibitor on properties of concrete, effect on corrosion of reinforcement,
and field tests and experience with corrosion inhibitors.
Chapter three yields the properties
of using materials in this study and experimental program. The studied
variables include; (1) presence of chloride, chloride content takes the values
of 0.20, 0.50, 0.80 and 1.4 of cement weight ;(2) presence of inhibitors and
its content. Concrete with Sikaferrogard® -901 with content of 8, 12, and 16
kg/m ’ was used. Concrete with MCl 2005 with content of 1.19 kg/m ’, and
concrete without inhibitors were also used. Slump test, compressive strength,
splitting tensile strength test and accelerated corrosion test were performed.
Cylinder specimens of75xl50 mm in dimension with steel bars of 12 mm diameter,
200 mm length placed in the middle of the specimens were used for accelerated
corrosion test with a concrete cover 3.5 em. After curing, the specimens were
placed in accelerated corrosion cell. The electrolyte in this cell was NaCl
solution. A constant volt of 30 DC was applied between the anode (steel reinforcement)
and cathode (copper plate). The current intensity was recorded with the time up
to the appearance of 3 mm longitudinal crack for control specimens and 2 mm for
other specimens .The time of the initial visible crack was also recorded during
test. Corrosion was evaluated through the time at first crack, the critical
time, the rate of weight loss of steel reinforcement and the critical corrosion
tendency factor.
Chapter
four contains the effect of using types of corrosion inhibitors with different dosages
on slump of concrete, compressive strength, splitting tensile strength,
relation between current intensity and time, the time at first crack, the
critical time, the rate of weight loss of steel reinforcement and the critical
corrosion tendency factor. Discussion about the results and the reasons of
improvement of corrosion resistance for corrosion inhibitors are also given in
this chapter.Corrosion of steel in concrete is the most important problem in
maintenance of concrete structures. However, this problem has serious effects
on infrastructure and economy that may be certainly reduced. This investigation
aims to study the effect of using corrosion inhibitors to enhance the
resistance of reinforcing steel against corrosion
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