Compositions: coating or plastic – Coating or plastic compositions – Metal-depositing composition or substrate-sensitizing...
Patent
1980-11-02
1982-12-28
Poer, James
Compositions: coating or plastic
Coating or plastic compositions
Metal-depositing composition or substrate-sensitizing...
106 97, 106314, 428378, 428457, 428470, C04B 735
Patent
active
043659993
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a corrosion-inhibiting method for steel materials in concrete or mortar and especially relates to a corrosion-inhibiting method for steel materials in concrete or mortar characterized in that the corrosion inhibitor comprises a nitrite, a glycine or glycine derivatives and a hydrazine hydrate.
BACKGROUND ART
Regulations concerning the gathering of aggregate materials for use in concrete have been made more rigorous year after year to protect disasters, natural environments and the like. For this reason, there has been a rapid switch to sea sands for use as fine aggregates in place of mountain sands and river sands. Each year the amount of sea sands used increases.
In reinforced concrete structures and the like wherein sea sands are used, there is a problem that the steel materials used in concrete, such as reinforcing bars, steel frames, lathes and the like, are rusted and corroded by the chlorides contained in sea sands. There is generally about 0.1 to 0.4% salinity in sea sands which have not been desalted. Thus it is very dangerous to use such sea sands without any treatment, because the possibility of said problem will occur is exceedingly high. Therefore, it is necessary to regulate the maximum amount of chlorides contained in sea sands to be used in reinforced concrete structures and the like. According to the 1975 Revised Edition of JASS (Japanese Architectural Standard Specification), the maximum amount of chlorides is 0.1 percent by weight calculated in terms of sodium chloride based on an absolute dry amount.
To prevent the aforesaid problem caused by chlorides contained in sea sands, there are two methods; a flushing method and a method using a corrosion inhibitor. There is a greater tendency to employ the latter method because the former method requires a large amount of clear water and is not easily carried out.
The use of nitrites, dichromates or mixtures thereof (Japanese Patent Publication No. 8021/1969), the use of a mixture of sodium nitrite and calcium nitrite (Japanese Patent Publication No. 20260/1978) and the like are already known as corrosion-inhibiting methods. However, these methods only teach a corrosion-inhibiting effect for sodium chloride and calcium chloride and do not explain a corrosion-inhibiting effect for the wide variety of salts present in sea water. Generally nitrites do not have a sufficient corrosion-inhibiting effect unless a relatively large amount of nitrites relative to the chlorides is used. Dichromates being harmful to the human body are not preferable from the viewpoint of avoiding environmental pollution.
The present invention has been developed in order to solve the aforesaid problem. The gist of the invention is the use of corrosion inhibitor which not only has an excellent corrosion-inhibiting effect for steel materials but also has no bad side effects upon such properties of concrete or mortar as coagulation, hardening, size stability, durability and the like.
DISCLOSURE OF THE INVENTION
The present invention provides a corrosion-inhibiting method for steel materials in concrete or mortar, characterized in that atoms) or salts thereof, and
The term "steel materials" as used in describing the present invention means reinforcing bars, steel frames and all other steel materials such as lathes used for such purposes as the prevention of a contraction and a cracking of concrete or mortar and other purposes.
The nitrites used in the present invention are alkali metal salts or alkaline earth metal salts of nitrous acid or mixtures thereof; sodium nitrite is especially preferable.
The salts of a compound represented by the aforementioned general formula [1] are alkali metal salts or alkaline earth metal salts of said compound or mixtures thereof; sodium salt of glycine is especially preferable.
The amounts to be used and the relative proportion of each component in the corrosion inhibitor of the present invention depend upon the amount of chlorides incorporated in the concrete or mortar and are therefore no
REFERENCES:
patent: 3668150 (1972-06-01), Horvitz
patent: 4012195 (1977-03-01), Noack
Fujita Toshio
Kashima Toru
Kiresuto Kagaku Kabushiki Kaisha
Osaka Semento Kabushiki Kaisha
Poer James
LandOfFree
Corrosion-inhibiting method for steel materials in concrete does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Corrosion-inhibiting method for steel materials in concrete, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Corrosion-inhibiting method for steel materials in concrete will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1335862