WO1994024068A1 - Procede de traitement du beton arme et/ou de son armature - Google Patents

Procede de traitement du beton arme et/ou de son armature Download PDF

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Publication number
WO1994024068A1
WO1994024068A1 PCT/GB1994/000802 GB9400802W WO9424068A1 WO 1994024068 A1 WO1994024068 A1 WO 1994024068A1 GB 9400802 W GB9400802 W GB 9400802W WO 9424068 A1 WO9424068 A1 WO 9424068A1
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WO
WIPO (PCT)
Prior art keywords
concrete
embedded steel
steel
embedded
current flow
Prior art date
Application number
PCT/GB1994/000802
Other languages
English (en)
Inventor
John Bruce Miller
Original Assignee
Norwegian Concrete Technologies A.S.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB9307783A external-priority patent/GB2277098A/en
Priority claimed from GB939307782A external-priority patent/GB9307782D0/en
Application filed by Norwegian Concrete Technologies A.S. filed Critical Norwegian Concrete Technologies A.S.
Priority to BR9406453A priority Critical patent/BR9406453A/pt
Priority to AU65096/94A priority patent/AU6509694A/en
Publication of WO1994024068A1 publication Critical patent/WO1994024068A1/fr

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Classifications

    • 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
    • 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
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/4505—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements characterised by the method of application
    • C04B41/4564—Electrolytic or electrophoretic processes, e.g. electrochemical re-alkalisation of reinforced concrete
    • 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
    • C04B41/61—Coating or impregnation
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G23/00—Working measures on existing buildings
    • E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G23/00—Working measures on existing buildings
    • E04G23/04—Propping of endangered or damaged buildings or building parts, e.g. with respect to air-raid action
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2201/00—Type of materials to be protected by cathodic protection
    • C23F2201/02—Concrete, e.g. reinforced

Definitions

  • Embedded steel in reinforced concrete is normally protected against corrosion by virtue of a dense oxide film which forms on the steel surface in alkaline environments. This film acts as a barrier to aggressive agents.
  • the passivating oxide film may break down thus rendering the embedded steel subject to corrosion.
  • chloride extraction in which chloride ions are caused to migrate under the influence of an electric field to an external electrolyte where they accumulate in, and eventually are removed with the electrolyte.
  • the Vennesland et al. U.S. Patent No 4,032,803 is an example of such processes.
  • the chloride extraction process though effective and less costly than cathodic protection, and thus a substantial improvement thereover, nevertheless suffers from the great and economically expensive practical difficulty of predicting the time necessary for the treatment to be completed. Because of this, frequent sampling and analysis of the concrete is required to determine remaining chloride levels. This difficulty is compounded by there so far being no residual chloride level which is generally accepted by the industry as being safe with regard to future chloride attack. These factors can make it difficult to calculate the cost and time necessary to reach a particular treatment target. In some cases, this time can also be unacceptably long from a practical aspect, especially since it is difficult to plan for in advance.
  • a third such method which is applied to carbonated concretes, is the impregnation of the carbonated zones by the electro-migration of alkaline substances from an external source.
  • the Miller et al U.S. Patent No 4,865,702 is illustrative of this process.
  • This latter method though successful in carbonated concretes which are low in chloride, can become inefficient or even fail, when the concrete contains significant amounts of ionic substances such as chlorides. Also when the concrete contains blast furnace cement, or where pozzolans have been added to the mix, the treatment time can become unreasonably long. Further problems arise where chloride setting accelerators have been used in the originating concrete mix whereby the chloride is consequently distributed throughout the concrete mass.
  • the documenting, monitoring and controlling of the chloride removal entails the taking of numerous core samples by, for example, diamond core drilling and then analysing the cores for chloride content.
  • core samples are notoriously inhomgeneous material so that statistically significant numbers of core samples need to be taken and analysed and documented to ensure effective monitoring of the chloride removal.
  • the taking of a core sample leaves a hole which needs to be filled.
  • the present invention overcomes the difficulties of the above mentioned methods by being highly predictable with regard to treatment time, by eliminating the necessity for sampling and chloride analysis, by being quicker and hence more economical to apply, and by being equally applicable to almost any kind of concrete, carbonated or not, chloride contaminated or not, pozzolanic or not, and whether or not blast furnace cement has been used.
  • a process for the electrochemical treatment of reinforcing steel in concrete having embedded steel reinforcement including applying an electroconductive material to an exposed surface of the concrete to form a distributed electrode, and applying a DC voltage to said electroconductive material as a positive terminal, and to said embedded steel reinforcement, as a negative terminal, and characterised by effecting passivation of the embedded steel and/or by imparting a predetermined modification to the bond strength between said embedded steel and said concrete including the steps of:-
  • the application of said DC voltage and said distributed current flow is continued until at least about 100 ampere-hours of current, per square metre of surface area of said embedded steel reinforcement, has passed between said terminals; and said treatment is discontinued before said current flow substantially exceeds 3000 ampere hours, per square metre of surface area of the embedded steel reinforcement, regardless of residual chloride levels and residual alkali levels in the concrete.
  • the present invention is based upon the discovery and recognition that the electrochemical treatment of concrete does not have to be controlled, for example, as a function of the chloride content or as a function of the degree of carbonation. Rather, the invention is based upon the recognition that the electrochemical processing of concrete is optimally controlled as a function of the surface area of the steel reinforcement.
  • the surface area of the embedded reinforcement is either known from the construction records or is the subject of a close approximation.
  • eletrochemical treatment can be set up more or less in a known manner as is disclosed by the Vennesland et al,. U.S. Patent No 4,032 ,803 or by the Miller U.S. Patent No 5,228,959.
  • the process is controlled by reference to the accumulated current flow in relation to the total surface area of the embedded reinforcing steel.
  • the process is continued until a minimum of 100 ampere-hours of current flow per square metre of surface area of the embedded steel has been realised.
  • the process can be discontinued at that stage (and preferably is discontinued before the current flow significantly exceeds 3000 ampere hours per square metre of surface area of the embedded steel), regardless of the residual chloride level or carbonation level at various points in the concrete.
  • the process may be discontinued at this stage with a high level of confidence that the embedded reinforcing steel will be protected for a significant period of time.
  • processing according to the present invention can be accomplished with less than half the energy input and processing time hitherto required.
  • Figure 1 is a schematic illustration of reinforced concrete set up for treatment in accordance with a first aspect the present invention
  • Figure 2 is a graphical representation illustrating the increasing passivity (and therefore protection) of embedded steel reinforcement over a period of time after treatment in accordance with the first aspect of the invention
  • Figure 3 is a simplified cross sectional illustration of a concrete structure illustrating the application of a second aspect of the invention
  • Figure 4 is a representative graph illustrating the relationships between treatment time according to the invention and its effect upon the bond strength between concrete and steel embedded therein.
  • FIG. 10 represents a concrete, comprised of set and hardened concrete 11 in which is embedded steel reinforcement 12, which can be of a known and conventional type.
  • steel reinforcement 12 can be of a known and conventional type.
  • the amount of reinforcing steel per unit of concrete may vary rather widely.
  • the concrete structure is a mature installation, in which the body of the concrete 11 has become contaminated by chloride ions, carbonation or other circumstances tending to create conditions favouring corrosion of the steel reinforcement 12.
  • a, D.C. power source designated by the letter "G"
  • G D.C. power source
  • G D.C. power source
  • the electrode structure 13 may comprise a mesh like material of suitably conductive material, such as steel wire mesh or titanium mesh, for example.
  • the electrode structure is embedded in an electrolytic medium 14 arranged in intimate contact with the exposed surface 15 of the concrete structure 10.
  • the electrolytic medium can be a liquid, appropriately pooled to cover the concrete surface. More preferably, the electrolytic medium is a self adherent conductive mass, such as a sprayed on mixture of cellulosic pulp fibre and water or other electrolyte. The fibre mass is applied in a first layer, prior to mounting the electrode structure 13 and in a second layer thereafter to embed completely the electrode structure within the conductive mass. It will be understood that other suitable materials could be used to form the requisite electrolytic mass.
  • a self-adherent electrolytic mass is desirable in many cases, as where the exposed concrete is, for example, vertical or downwardly facing or where the surface of the concrete is convoluted or very rough.
  • distributed electrode such as conductive surface coatings, foil layers placed in direct contact with the concrete surface, spongy blankets in certain cases etc.
  • the particular form of distributed surface electrode is not critical to the invention, as long as it functions effectively to distribute the current flow effectively over the surface area of the embedded steel reinforcement. Generally this objective is realised by distributing the current from the external distributed electrode 13 relatively uniformly over the exposed surface of the concrete structure.
  • a direct electric current of at least 0.1 amperes per square metre of surface area of the embedded steel reinforcement 12 is caused to flow between the reinforcement steel, which is negatively connected, and the external electrode which is positively connected to function as an anode.
  • the output voltage of the DC power source “G” may vary between wide limits, but it should be designed to deliver sufficient charge at the minimum current density mentioned above. In practice, it has been found convenient to use a power source “G” capable of being adjusted to between 5 and 40 volts DC output, and with sufficient current capacity to deliver between 0.5 and 10 amperes per square metre of surface area of the embedded steel.
  • the output of the power source can be monitored by suitable voltage and current meters "V" and "A" as shown.
  • the current is passed for the time necessary to give a total charge of at least about 100 amperes per square metre of surface area of the embedded steel reinforcement 12.
  • the total charge should not exceed about 3000 ampere-hours per square metre of steel surface area, because the energy consumed is largely wasted and does not achieve significant benefit.
  • the treatment of the invention is required only to deal with chloride removal the total charge can be in the order of 1000 amperehours per square metre of steel surface area. Whilst higher charge levels can be used it is useful to note that a total charge of as high as 10,000 ampere-hours per square metre of steel surface area could actually be detrimental, causing degredation of the concrete.
  • the current is switched off, the entire installation is removed, and the external conductive material, if removable, is removed.
  • the steel will then have been given long term protection by being conditioned to become strongly passivated.
  • the electrochemical cathodic reactions caused by the action of the current at the steel surface lead to the production of for instance sodium hydroxide which is produced in sufficient quantities to impregnate the pores of the concrete surrounding the steel and thus render the environment highly alkaline.
  • the steel When the current is then switched off, after a suitable treatment charge has been delivered, the steel will begin to repassivate by virtue of it now being in a clean active condition in a chloride-free, highly alkaline environment. Under these relatively ideal conditions, the steel will oxidise to produce the dense oxide film necessary to protect the steel from corrosion. This oxidation process is actually a special form of corrosion which results in the formation of the very dense protective oxide film known as the passivating film.
  • this film is easily followed by monitoring the electrical potential of the steel in relation to a standard reference half cell 16, such as silver/silver oxide, lead/lead oxide, copper/copper sulphate, etc.
  • the reference cell 16 should preferably, though not necessarily, be installed in a fixed position near to the steel to be monitored, for example, by grouting into a drilled hole 17 in the concrete.
  • a diagram can then be drawn up showing the change in potential with time, an example of which is shown in Figure 2 of the drawings.
  • Such a diagram will show that the passivation process, which commences as soon as the processing current is discontinued, extends over a long period of time.
  • the reference cell monitoring is sufficiently prolonged, it will show when the steel gains the potential commonly considered as being safe from a corrosion point of view. Indeed, if sufficiently prolonged, it can also show whether or not the steel ever again becomes subject to corrosion, by noting whether the potential again passes the value associated with corrosion, but from the opposite direction.
  • the reference potential measured with a suitable volt meter 18, between the lead/lead oxide half cell 16 and the steel reinforcement 12, increases slowly, over a period of several months. Starting from an initial potential of about 0 millivolts, the reference potential gradually increases to about +500 millivolts (considered relatively safe, from a corrosion standpoint), in a period of around seven weeks. After a year, the reference potential has continued to increase to a level of around +700 millivolts. It should be noted that depending upon the nature of the concrete involved other potential values could be applicable.
  • the process of the present invention involving processing of a concrete structure according to the surface area of the embedded reinforcement, enables the processing time to be accurately predicted in advance, whereas controlling in accordance with the remaining chloride levels requires the periodic taking and testing of core samples from the material under treatment and cannot be predicted in advance. Moreover, by the time the testing of the core indicates that chloride levels have been reduced to targeted levels, it can be expected that processing will have been carried on for a time far beyond that required to achieve the ampere-hour per square metre of surface levels known to be effective under the proposals of the present invention.
  • concrete structures may vary widely in the amount of internal embedded reinforcement per unit of concrete.
  • steel to concrete ratios vary between 0.2 and 2 square metres of steel surface area per square metre of concrete surface.
  • a more typical range is between 0.3 and 1 square metre of steel surface area per square metre of concrete surface.
  • the required corrosion protection can be achieved by treating the defective part of the structure only.
  • a further feature of the process of the invention arises in practical installations in which no part of the structure is readily available for sufficient time for adequate treatment to be effected (for example, as would be the case of a bridge structure having to be closed to traffic for the duration of a treatment lasting several weeks).
  • this aspect of the invention enables a main structure to be given a lasting corrosion protection by treatment of a part of the actual structure it is required to treat or by treatment of an extension to the actual structure it is required to treat.
  • the amount of current flow necessary to give a lasting protection is a function of the area of a structure available for treatment, and that it is desirable to restrict the maximum current to a level that can safely be used without introducing any undesirable side effects.
  • the steel reinforcement needs to be charged at a level corresponding to 1000 ampere/hours per square metre thereof.
  • This protection can for example, in practice, be achieved by treating the whole area at one ampere/hour per square metre for 1000 hours, by treating one half of the area at 2 ampere/hours per square metre for 500 hours, by treating one tenth of the area at 10 ampere/hours per square metre for 100 hours, or by any other proportional conbination.
  • the above numerical data figures are for guidance only since precise figures will depend upon the geometry of the structure and other parameters such as the chemical/physical nature of the concrete.
  • An additional aspect of the present invention relates to a realisation that the application of the DC voltsge between the embedded steel and the concrete can be used to modify and establish targeted bond strengths between the concrete and embedded steel. That is to say the process for the electrochemical treatment of hardened concrete can be used in order to modify (i.e., by increasing or decreasing) the bond strength between hardened concrete and internally embedded steel, particularly reinforcing bars, pretensioning or post tensioning rods or cables.
  • this has been impossible, since there has been no known procedure for controllably changing the steel-to-concrete bond, in situ, in hardened concrete.
  • An additional aspect of the invention involves the modification of the steel-to-concrete interface in a hardened concrete structure to enhance the seal at such interface.
  • the interface seal between embedded steel reinforcing or tensioning elements is less than perfect, due to accumulation of bleeding water at the steel surface during the initial hardening of the concrete, or possibly due to insufficient compaction of _ _
  • the present aspect of the invention is based partly upon the discovery that, during the electrochemical treatment of concrete for the reasons so far discussed, by utilising the internally embedded steel as a cathode, and a distributed electrode structure structure spaced therefrom, typically at an exposed surface of the concrete as an anode, a marked change occurs in the bond between the embedded steel and the surrounding concrete, as a function of the electrical charge applied.
  • a marked change occurs in the bond between the embedded steel and the surrounding concrete, as a function of the electrical charge applied.
  • an initial phase of the treatment there is a progressive and significant reduction in the bond strength to a level far below the initial bond strength.
  • This is followed, with continued treatment, by a progressive and significant increase in bond strength. It has been observed that this variation in bond strength is both predictable and repeatable for given types of concrete. Accordingly, by establishing a simple database of relationships between a given treatment time and its effect upon the steel-to-concrete bond strength, it becomes possible predictably to modify such bond strength in an existing structure.
  • treatment conditions and controlling parameters are different than for those involved in other aspects in the treatment of a concrete structure.
  • the bonding at the steel-to-concrete . interface is modified by passing an electrical current between the embedded steel and a distributed electrode associated with the concrete, at a location spaced from the embedded steel.
  • Figure 3 shows a typical and advantageous arrangement for the accomplishment of that objective.
  • the reference numeral 10 designates a reinforced (or pre-tensioned of post-tensioned) concrete structure.
  • a concrete body is provided with a plurality of reinforcing bars 12, which are embedded in and surrounded by the concrete.
  • a source “G” of DC voltage is connected at its negative side to the embedded steel elements 12 and at its negative side to a distributed electrode element 13, which may be in the form of a conductive wire mesh, for example, of steel or titanium.
  • the electrode element 13 is embedded in an electrolytic mass 14, which advantangously may be a cellulosic pulp fibre, for example, maintained moist with water or electolytic solution.
  • the cellulosic pulp fibre typically is sprayed onto the outer surface 15 of the concrete 11 in two layers.
  • the fibrous material is self-adherent to the surface of the concrete, and thus may be applied to the vertical or even downwardly facing surfaces.
  • the electrode 13 may be submerged in a pool of liquid, or embedded in a wet , spongy mass or blanket, for example.
  • the surface of the concrete may be coated with a conductive layer (or placed in contact with a conductive foil).
  • the principal requirement, for the purposes of the present invention, is to provide an area-distributed electrode arrangement, to accommodate a distributed flow of electricity between the internally embedded steel elements 12 and the opposite electrode.
  • the operating capacity of the voltage source "G" is not critical. Practical considerations, however, suggest that DC voltage may be made available at from 5 to about 40 volts DC, preferably adjustable. 50 volts is a convenient upper limit for safety purposes.
  • the system desirably has a sufficient current capacity to deliver between 0.5 and 10 amps of current, per square metre of surface area of embedded steel in the area being processed .
  • FIG. 4 of the drawings there is shown a typical curve of values of steel-to-concrete bond strength, in MPa (Megapascals) in relation to the total electrical charge applied to the embedded steel, in terms of ampere-hours per square metre of surface area of the embedded steel.
  • the solid line represents an average of values for a concrete of typical composition.
  • the upper and lower dotted lines represent typical deviations from the average values represented by the solid line.
  • the bond strength between the embedded steel and the surrounding concrete progressively diminishes.
  • the starting bond strength is approximately 1.8 MPa, and this progressively reduces to a value of around 0.6-0.7 MPa, after a current flow of around 3000 ampere hours per square metre of steel surface area.
  • bond strength After reaching its maximum values, bond strength again begins to decrease with continued current flow, although it ultimately levels off and becomes relatively stable at current flow in the range 14000-15000 ampere hours per square metre of surface area. Normally, there would be no reason to carry the process beyond the point of maximum bond strength. Indeed, it may be detrimental to do so.
  • the process of the invention achieves remarkable and unexpected results in enabling for the first time, the in situ modification of steel-to-concrete bond strength in a hardened concrete structure.
  • the bond strength may be controllably decreased, as may be desired in installations utilising pre-tensioned or post tensioned tendons, or increased, as in the case of standard static reinforcing bars embedded in a typical concrete structure.
  • a database of values for a typical concrete composition is easily produced and can serve acceptably for most types of concrete. For particularly critical structures and/or for unique concrete formulations, a relatively simple set of tests can be performed to establish a specific database of values for a specific composition of concrete. These values can then be followed in controlling the process as applied to a particular structure utilising the special 5 composition.
  • the process of the invention can also be utilised to seal effectively the steel-to-concrete interface against the ingress of water ⁇ . Q and atmosphere. This is the result of the precipitation of reaction products in the interstices of the concrete at and immediately surrounding the steel-to-concrete interface, which makes the concrete in this area relatively impenatrable to external liquids and gases.
  • the process of the invention is simple and economical to apply, and utilises known technology and known equipment.
  • the external electrode means can be installed on an exterior surface of the structure and then washed away or otherwise removed upon completion of the

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  • Chemical & Material Sciences (AREA)
  • Architecture (AREA)
  • Ceramic Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
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  • Working Measures On Existing Buildindgs (AREA)
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Abstract

Procédé de traitement électrochimique de l'acier de renfort du béton possédant une armature d'acier noyée. Le procédé consiste à appliquer un matériau électroconducteur sur une surface exposée du béton de façon à former une électrode. Le procédé consiste ensuite à appliquer une tension continue audit materiau conducteur constituant une borne positive et à ladite armature d'acier noyé constituant une borne négative. La passivation de l'acier noyé et/ou la modification prédéterminée de la force de liaison entre ledit acier noyé et ledit béton sont réalisées par application de ladite tension continue entre lesdites bornes, qui provoque l'apparition d'un courant entre ledit matériau conducteur, anode, et ladite armature d'acier noyé, cathode. L'application de ladite tension continue et dudit courant est maintenue en accord avec un régime de traitement courant/temps prédéterminé, tel que la valeur du courant par mètre carré de surface de ladite armature d'acier noyé passant entre lesdites bornes pendant une période prédéterminée, soient comprises entre des limites prédéterminées.
PCT/GB1994/000802 1993-04-15 1994-04-15 Procede de traitement du beton arme et/ou de son armature WO1994024068A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BR9406453A BR9406453A (pt) 1993-04-15 1994-04-15 Processo para o tratamento eletroquímico de aço de reforço em concreto
AU65096/94A AU6509694A (en) 1993-04-15 1994-04-15 Method for treating reinforced concrete and/or the reinforcement thereof

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9307783.2 1993-04-15
GB9307783A GB2277098A (en) 1993-04-15 1993-04-15 Electrochemical process for adjusting the steel-to-concrete bond strength and improving the sealing of the steel-concrete interface
GB939307782A GB9307782D0 (en) 1993-04-15 1993-04-15 Method for passivating steel in carbonated and/or chloride contaminated concrete
GB9307782.4 1993-04-15

Publications (1)

Publication Number Publication Date
WO1994024068A1 true WO1994024068A1 (fr) 1994-10-27

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AU (1) AU6509694A (fr)
BR (1) BR9406453A (fr)
CA (1) CA2160575A1 (fr)
GB (1) GB2277099A (fr)
WO (1) WO1994024068A1 (fr)

Cited By (1)

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CN112626981A (zh) * 2019-09-24 2021-04-09 维特根有限公司 监测混凝土压实度的滑模摊铺机的监测装置和滑模摊铺机运行期间监测混凝土压实度的方法

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Publication number Priority date Publication date Assignee Title
DE20100219U1 (de) 2001-01-08 2001-07-05 Bothor Kerim Patrick Vorrichtung zur Aufnahme, Transport, kontrollierten Entleerung und Lagerung von fliessfähigen Schüttgütern in grossvolumigen Behältern
CN106518158B (zh) * 2016-11-07 2018-08-14 河海大学 一种提高硅烷在混凝土中渗透深度的方法

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EP0401519A1 (fr) * 1989-06-09 1990-12-12 John B. Miller Procédé pour le traitement électrochimique de matériaux de construction poreux, en particulier pour le séchage et la réalcalinisation

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BE795304A (fr) * 1968-11-21 1973-05-29 Inst Cercetari Constructi Procede et dispositif pour eliminer des efflorescences salines de surfaces brutes ou peintes
US4440605A (en) * 1981-02-13 1984-04-03 The Marine Resources Company Repair of reinforced concrete structures by mineral accretion
WO1987006521A1 (fr) * 1986-05-02 1987-11-05 Noteby Norsk Teknisk Byggekontroll A/S Re-alcalinisation electrochimique du beton
EP0398117A2 (fr) * 1989-05-16 1990-11-22 Oystein Vennesland Procédé pour la réhabilitation du béton renforcé intérieurement par enlèvement des chlorures
EP0401519A1 (fr) * 1989-06-09 1990-12-12 John B. Miller Procédé pour le traitement électrochimique de matériaux de construction poreux, en particulier pour le séchage et la réalcalinisation

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112626981A (zh) * 2019-09-24 2021-04-09 维特根有限公司 监测混凝土压实度的滑模摊铺机的监测装置和滑模摊铺机运行期间监测混凝土压实度的方法

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GB9407507D0 (en) 1994-06-08
CA2160575A1 (fr) 1994-10-27
BR9406453A (pt) 1996-01-02
GB2277099A (en) 1994-10-19

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