EP 0839123 A1 19980506 - CALCIUM HYDROXIDE RE-ALKALIZATION METHOD
Title (en)
CALCIUM HYDROXIDE RE-ALKALIZATION METHOD
Title (de)
CALCIUMHYDROXID-REALKALISIERVERFAHREN
Title (fr)
PROCEDE DE RE-ALCALINISATION A L'HYDROXYDE DE CALCIUM
Publication
Application
Priority
- CH 9700171 W 19970429
- CH 125996 A 19960519
Abstract (en)
[origin: WO9744295A1] A method is presented for restoring the alkaline environment in carbonatized top layers of concrete, by activating the calcium hydroxide contained in the concrete. By analogy to observed natural processes, an electrochemical method is described that is intended to re-alkalize the carbonatized top layer, and re-passivate the steel reinforcements that are no longer protected from corrosion by an alkaline environment by means of drying/humidification cycles. This method presupposes parts made of conventional concrete, having the components hardened cement paste, rock aggregate, and capillary pores. The alkaline cement paste, with a pH value of 11-13, is altered chemically over time to carbonatized cement paste with a pH value below 9-10, under the influence of atmospheric carbon dioxide. In contrast to alkaline cement paste, the latter offers no protection against corrosion to the steel reinforcing rods that are immersed in the concrete in reinforced-concrete structures. Increasing risks of corrosions result for civil and structural engineering constructions such as bridges and in industrial constructions. Early recognition of the problem, and restoration of the alkaline environmental conditions for the concrete reinforcements, which protect them from corrosion, contribute to preserving the durability of the construction material.
IPC 1-7
IPC 8 full level
C04B 41/45 (2006.01)
CPC (source: EP)
C04B 41/4566 (2013.01)
Citation (search report)
See references of WO 9744295A1
Designated contracting state (EPC)
AT CH DE LI
DOCDB simple family (publication)
WO 9744295 A1 19971127; CH 692297 A5 20020430; EP 0839123 A1 19980506
DOCDB simple family (application)
CH 9700171 W 19970429; CH 125996 A 19960519; EP 97919236 A 19970429