Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/64—Insulation or other protection; Elements or use of specified material therefor for making damp-proof; Protection against corrosion
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/53—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone involving the removal of at least part of the materials of the treated article, e.g. etching, drying of hardened concrete
  • C04B41/5369—Desalination, e.g. of reinforced concrete
  • C04B41/5376—Electrochemical desalination
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
  • B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
  • B28B11/245—Curing concrete articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
  • B28B23/02—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/60—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only artificial stone
  • C04B41/72—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only artificial stone involving the removal of part of the materials of the treated articles, e.g. etching

Definitions

• the present invention relates to a process for the treatment of concrete, of the kind recited in the introduction to claim 1.
• One method is to seal the concrete with a surface coating which will prevent penetration of the corrosion-promoting substances, such as chloride ions, sulphate ions, carbon dioxide and oxygen.
• the corrosion-promoting substances such as chloride ions, sulphate ions, carbon dioxide and oxygen.
• Another way of meeting the problem is by way of cathodic protection with applied voltage.
• a general problem with this method is regulating the voltage.
• a particular problem is that the method may not be employed in prestressed constructions.
• the object of the present invention is precisely to provide a process which makes it possible to remove ions from concrete in a more rapid, reasonable and reliable manner than has been possible with known processes.
• the process according to the invention is characterised by the features which are recited in the characterising portion of claim 1.
• the concentration will usually be 1 molar.
• a suitable anode material is nickel, which however is rela ⁇ tively expensive. Alternatively there is used for example rust- free steel.
• the anode preferably has the form of a fine-meshed cloth, which ought to cover the surface of the concrete as much as possible.
• the first step in the treatment will be moistening with water, for example by irrigation with rising temperatures to at least 80°C in the moistening period.
• water-soluble salts, especially chlorides, on or near the surface of the concrete will go into solution, while the water dissolves the salts deeper within the concrete to a lesser degree.
• the salt (and thereby ion) concen ⁇ tration in the water will even out, that is to say ions will migrate towards and on the surface of the concrete.
• the duration and here moistening will vary with several factors, for example temperature and the quality of the concrete. In tests moistening for 1/2 - 3/4 hour has been employed.
• the water on the surface of the concrete will evaporate, and according to the invention the evaporation is accelerated by feeding hot air ; whereby salts which are in solution will migrate towards that location where the heat is supplied and the evaporation effected, namely the surface of the concrete.
• salts are leached out of the concrete, and by moistening again the water penetrates further down in the concrete and dissolves salts.
• the ions which have passed into solution are drawn towards the surface of the concrete.
• the moistening/drying cycle can be repeated a number of times which is also dependent upon several parameters such as temperature, the quality of the concrete and the covering of the reinforcing steel. Moistening and drying 2-3 times appears to be appropriate in practice.
• Preferably it contains an ion exchange resin, which can "catch" ions before they reach the anode where chloride ions will be able to cause the generation of chlorine gas.
• electrolysis voltages of over 50 volts are used. After conclusion of the elctrolysis the concrete is washed and dried after which it is sealed if necessary with a material knov/n per se.
• the concrete is moistened with water at temperatures rising uniformly to about 80° over 1/2 - 3/4 hour, after which it is dried with hot air in approximately the same time period. Moistening/drying is repeated two or three times. Thereafter the concrete is dried again over an equally long time, after which it is subjected to electrolysis with the reinforcement as cathode. After conclusion of the electrolysis the moistening/drying is repeated if necessary. Thereafter the concrete is dried and sealed.
• the process can be begun with drying and thus the first moistening can be omitted.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Structural Engineering (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Architecture (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Water Supply & Treatment (AREA)
• Electrochemistry (AREA)
• Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Electromagnetism (AREA)
• Civil Engineering (AREA)
• Aftertreatments Of Artificial And Natural Stones (AREA)
• Processing Of Solid Wastes (AREA)
• Fire-Extinguishing Compositions (AREA)
• Working Measures On Existing Buildindgs (AREA)
• Water Treatment By Electricity Or Magnetism (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19890692

Family Applications (1)

Country Status (4)

Cited By (7)

Families Citing this family (1)

Citations (4)

• 1988
  • 1988-02-26 NO NO88880840A patent/NO880840L/no unknown
• 1989
  • 1989-02-23 WO PCT/NO1989/000014 patent/WO1989008170A1/en unknown
  • 1989-02-23 KR KR1019890701955A patent/KR900700705A/ko not_active Application Discontinuation
  • 1989-02-23 AU AU31899/89A patent/AU3189989A/en not_active Abandoned

Patent Citations (4)

Non-Patent Citations (1)

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