A METHOD FOR FIXING AN ELECTRODE ARRANGEMENT TO BE USED IN THE CATHODIC PROTECTION OF CONCRETE STRUCTURES AND A FIXING ELEMENT

Abstract: The invention relates to a method for fixing an electrode arrangement to be used in the cathodic protection of concrete structures. In the method, an anode (20) is mounted in a framework (11) and the framework with its anodes is mounted on the concrete structure at a production plant or in the mounting step before the concreting step. The invention also relates to a fixing element (10) of the electrode arrangement to be used in the cathodic protection of concrete structures, which fixing element is comprised of an anode (20) and a framework (11), which framework (11) is provided with means (15) for fixing the element (10) to the concrete structure.

Description: A method for fixing an electrode arrangement to be used in the cathodic protection of concrete structures and a fixing element The invention relates to a method for fixing an electrode arrangement to be used in the cathodic protection of concrete structures. The invention also relates to a fixing element of an electrode arrangement to be used in the cathodic protection of concrete structures. In the protection of steel parts of concrete structures, e.g. concrete reinforce¬ ments, the anodes of an electrode arrangement are generally fixed to an existing concrete surface, and the anode is covered with shotcrete or with another corresponding conductive material. However, problems have been caused by the poor fixability of the electrode arrangement during the casting. Additional problems have also been caused by the fact that the anode is during the casting bent into contact with the steel constructions to be protected. The above-mentioned situtations have made it considerably more difficult and slower to carry out the actual concrete casting. The object of the present invention is to provide such an anode fixing arrange- ment and method, which, when used, eliminates the above-mentioned problem situations. Another object of the invention is to provide such a fixing arrangement, which well adapts itself to be used in continuos concreting applications. For reaching the objects mentioned above and to be presented below, the inventive method is mainly characterized in that the anode is mounted in a framework and that the framework with its anodes is mounted on the concrete structure at a production plant or in the mounting step before the concreting step. The inventive fixing element is mainly characterized in that the fixing element is comprised of an anode and a framework, which framework is provided with means for fixing the element to the concrete structure. Such an inventive anode element placed in position before the concreting is in certain cases the only technically sensible solution. When, for example, protecting underwater concrete structures, a considerable advantage is obtained in the preparation step, when the anode arrangement is of an element-structional type. When using the inventive anode fixing arrangement, the pressing effect of the additional mass caused by shotcreting is avoided. Furthermore, the number of the work phases needed decreases, since the anode element is prefabricated, and only the fixing of the anode element has to be performed in connection with concreting. The fixing of the inventive element is easy and it saves mounting time, since a separate fixing and insulating work of the anode in the mounting step is elimin¬ ated. The inventive element remains fixed on the concrete structures, whereby no special precautionary measures are needed in the concreting step, e.g. it is not necessary to use a slower concreting rate. The construction of the anode element according to the invention is mechanical¬ ly rigid such that it cannot come into an electrical contact with the concrete reinforcements to be protected. From the point of view of the operation of the protection, the avoidance of the electrical contact is one of the basic prerequi¬ sites. In addition, the inventive anode element cannot move during the concret¬ ing owing to its fixing means. When using the inventive element, the uninterruptibility of a cathodic contact is also ensured, since the connection of all concrete reinforcement layers to the cathode circuit can be guaranteed by means of several fixing points. The anode element according to the invention forms a system of several elements such that each element can, when so desired, be controlled as a sepa¬ rate electric circuit. The operation of the anode system is thereby ensured. The invention is next described in more detail with reference to the figures of the accompanying drawing, to which the invention is, however, in no way narrowly limited. Fig. 1A and IB show schematically an inventive anode element. Fig. 2 shows as a schematic partial view an inventive anode element fixed to a concrete structure. An inventive anode element 10 shown in Fig. 1A and IB comprises a framework 11, anodes 20 and fixing means 15. The framework 11 is made of an electrically insulating material, e.g. of plastics or ceramics or of an electrolytically conductive material, e.g. of concrete, plastics or ceramics. When so desired, a steel reinfor¬ cement or some other reinforcement is used for improving the strength prop¬ erties of the framework 11, which is, however, not necessary. In one preferred embodiment of the invention, the framework 11 of the anode element 10 is made of concrete, since a good adherence to the concreting is then obtained. Furthermore, when the framework 11 is made of concrete, possible detrimental heat expansion phenomena are eliminated. The anode element 10 is fixed to a concrete surface, to concrete reinforcements or to other fixed parts of the construction or to parts used during the mounting with the fixing means 15 of the framework 11, e.g. with plastic hooks, nails, wires, screws or the like. The fixing means 15 shown in Fig. 1A and IB are made of concrete reinforce¬ ment pins, which are fixed to the concrete reinforcements of the actual concrete reinforcement structure. The anode 20 is placed in the concreting of the framework 11, or the anode 20 is mechanically fixed e.g. with metallic or plastic nails, screws, anchors, lists or the like to the framework 11. The anode 20 is located on the opposite side relative to the fixing means 15 of the framework 11. The anode 20 is a net, wire, strip, rod, plate or the like. The material used in the anode 20 is a composite material, e.g. an alloy-metal coated titan, magnetite, platinated titan or an iron mixture, e.g. ferrosilicon or graphite or a noble metal, e.g. platinum or a conductive plastic. As described above, the anode element 10 can either be comprised of the material of the anode 20 or of the material of the anode 20 and another material joined thereto. Several anode elements 10 form a system, by means of which the steel parts of the concrete structure can be cathodically protected. Electricity is supplied to the anode element 20 e.g. via a conductor 30. The electricity is supplied separately to each anode element 20 via one or more of its points or to all anode elements 20 of the system together or by means of some combination of the two separate above-mentioned systems. The framework 11 of the anode element is arranged in a wedge-like form such that the width of the crosspiece of the framework 11 is on the side of the anode 20 greater than on the side of the fixing means 15, whereby the concrete can during the casting easily flow also inside the framework. In accordance with Fig. 2, the anode element 10 is fixed to the steel parts 50 of the concrete reinforcement structure so that the fixing means 15 of the anode element 10 are fixed to the steel parts 50. The anode element 10 is fitted between the outermost concrete reinforcement layer and the concreting wood hning 60, into which the concrete 70 is cast. As shown in Fig. 2, the anodes 20 of the anode element 10 are located on the other side of the framework 11 relative to the steel parts 50, whereby the anode 20 cannot come into contact with the steel parts 50. The invention has above been described only with reference to an example of its preferred embodiment. However, the intention is in no way to limit the invention to this example, but many changes and modifications are possible within the inventive idea defined in the following patent claims.

Claims: Claims 1. A method for fixing an electrode arrangement to be used in the cathodic protection of concrete structures, characterized in that an anode (20) is mounted in a framework (11) and that the framework with its anodes is mounted on the concrete structure at a production plant or in the mounting step before the concreting step. 2. A fixing element of an electrode arrangement to be used in the cathodic protection of concrete structures, characterized in that the fixing element (10) is comprised of an anode (20) and a framework (11), which framework (11) is provided with means (15) for fixing the element (10) to the concrete structure. 3. A fixing element according to Claim 2, characterized in that the framework (11) is made of concrete.

Inventors: PULLIAINEN MARTTI, RAEMOE TARJA, PULLIAINEN, MARTTI, RAEMOE, TARJA
Applicants: SAVCOR CONSULTING OY, SAVCOR-CONSULTING OY
Application year: 1991
Main classification: C23F13
IPC codes: C23F13