Institute of Building Materials Research Conservations Repair and Polymer Composites RWTH Aachen University, Germany “Who`s managing the quality in the concrete repair market“ FEREB/University of Liege Concrete Repair to EN 1504: Diagnosis, Design, Principles and Practise Univ.-Prof. Dr.-Ing. Michael Raupach

Liege_1504_Rau.pptx 2 Outline Introduction Structure of the EN 1504 parts 1-10 General procedure: Diagnosis – Repair – Maintenance Systematic Approach for Design: Options – Principles – Methods – Products Conclusions and outlook

Liege_1504_Rau.pptx 3 Structure of EN 1504

Liege_1504_Rau.pptx 4 Common Causes of Defects

Liege_1504_Rau.pptx 5 ENV

Liege_1504_Rau.pptx 6 Repair Strategy – Range of Options Do nothing for certain time There is a great variety of options, such as: Re-analysis of structural capacity, possibly leading to down- grading of the function of the concrete structure Prevention or reduction of further deterioration, without improvement of the concrete structure Improvement, strengthening or refurbishment of all or part of the concrete structure Reconstruction of part or all of the concrete structure Demolition of all or part of the concrete structure

Liege_1504_Rau.pptx 7 ENV

Liege_1504_Rau.pptx 8 Principles for Repair and Protection for Damages of the Concrete Principle No.Principle and its definition Principle 1 [PI]Protection against Ingress Principle 2 [MC]Moisture Control Principle 3 [CR]Concrete Restoration Principle 4 [SS]Structural Strengthening Principle 5 [PR]Physical Resistance Principle 6 [RC]Resistance to Chemicals

Liege_1504_Rau.pptx 9 Principles for Protection against Reinforcement Corrosion Principle No.Principle and its definition Principle 7 [RP]Preserving of Restoring Passivity Principle 8 [IR]Increasing Resistivity Principle 9 [CC]Cathodic Control Principle 10 [CR]Cathodic Protection Principle 11 [CA]Control of Anodic Areas

Liege_1504_Rau.pptx 10 ENV

Liege_1504_Rau.pptx 11 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 1 [PI] Protection against ingress Reducing or preventing the ingress of adverse agents, e.g. water, other liquids, vapour, gas, chemicals and biological agents 1.1 Hydrophobic impregnation Applying liquid products which penetrate the concrete and block the pore system 1.2Impregnation 1.3 Coating 1.4 Surface bandaging of cracks 1.5 Filling of cracks 1.6 Transferring cracks into joints 1.7Erecting external panels a 1.8Applying membranes a a These methods may also be applicable to other principles

Liege_1504_Rau.pptx 12 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 2 [MC] Moisture control Adjusting and maintaining the moisture content in the concrete within a specified range of values 2.1Hydrophobic impregnation 2.2Impregnation 2.3Coating 2.4Erecting external panels 2.5Electrochemical treatment Applying a potential difference across parts of the concrete to assist or resist the passage of water through the concrete (not for reinforced concrete without assessment of the risk of inducing corrosion)

Liege_1504_Rau.pptx 13 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 3 [CR] Concrete restoration Restoring the original concrete of an element of the structure to the originally specified shape and function Restoring the concrete structure by replacing part of it 3.1Hand-applied mortar 3.2Recasting with concrete or mortar 3.3Spraying concrete or mortar 3.4Replacing elements

Liege_1504_Rau.pptx 14 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 4 [SS] Structural strengthening Increasing or restoring the structural load bearing capacity of an element of the concrete structure 4.1Adding or replacing embedded or external reinforcing bars 4.2Adding reinforcement anchored in pre-formed or drilled holes 4.3Bonding plate reinforcement 4.4Adding mortar or concrete 4.5Injecting cracks, voids or interstices 4.6Filling cracks, voids or interstices 4.7Prestressing – (post tensioning)

Liege_1504_Rau.pptx 15 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 5 [PR] Increasing physical resistance Increasing resistance to physical or mechanical attack 5.1Coating 5.2Impregnation 5.3Adding mortar or concrete Principle 6 [RC] Resistance to chemicals Increasing resistance of the concrete surface to deteriorations by chemical attack 6.1Coating 6.2Impregnation 6.3Adding mortar or concrete

Liege_1504_Rau.pptx 16 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 7 [RP] Preserving or restoring passivity Creating chemical conditions in which the surface of the reinforcement is maintained in or is returned to a passive condition 7.1Increasing cover with additional mortar or concrete 7.2Replacing contaminated or carbonated concrete 7.3Electrochemical realkalisation of carbonated concrete 7.4Realkalisation of carbonated concrete by diffusion 7.5Electrochemical chloride extraction

Liege_1504_Rau.pptx 17 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 8 [IR] Increasing resistivity Increasing the electrical resistivity of the concrete 8.1Hydrophobic impregnation 8.2Impregnation 8.3Coating Principle 9 [CC] Cathodic control Creating conditions in which potentially cathodic areas of reinforcement are unable to drive an anodic reaction 9.1Limiting oxygen content (at the cathode) by saturation or suface coating

Liege_1504_Rau.pptx 18 Principles and Methods for Protection and Repair of Concrete Structures Principle No. Principle and its definition Methods based on the principle Principle 10 [CP] Cathodic protection10.1Applying an electrical potential Principle 11 [CA] Cathodic of anodic areas Creating conditions in which potentially anodic areas of reinforcement are unable to take part in the corrosion reaction 11.1Active coating of the reinforcement 11.2Barrier coating of the reinforcement 11.3Applying corrosion inhibitors in or to the concrete

Liege_1504_Rau.pptx 19 ENV

Liege_1504_Rau.pptx 20 “Performance Characteristics“ of Surface Protection Systems for Relevant Methods and Principles acc. to EN

Liege_1504_Rau.pptx 21 Examples of the Application of the Classification System for three Selected Cases Given in EN

Liege_1504_Rau.pptx 22 EN 1504 – Product Standards Selection of performance characteristics by the designers in most cases to complicated Product suppliers provide products with most relevant performance characteristics Some important points are missing in EN 1504: -Specification of coating systems -Special performance characteristics -Special points in the test method standards → Corrections require a lot of time!

Liege_1504_Rau.pptx 23 Maintenance Following Repair A precise time schedule for inspections Depending on the principles, methods and products used in a special case, maintenance should include: The system of inspection which is to be used, how results are to be recorded A specification for continuous treatment (if any is required), for example cathodic protection or monitoring equipment A statement of precautions to be taken or prohibitions to be enforced, for example maintenance of surface water drainage, maximum pressure for washing or prohibition of the use of de-icing salt. A maintenance management system should be implemented to ensure that the required maintenance is carried out !

Liege_1504_Rau.pptx 24 Conclusions The series of standards EN 1504 parts 1-10 privides a systematic framework for protection and repair of concrete structures including -Design principles (part 9) -Products (CE, parts 2-8) -Execution (part 10) and -Quality control Quality ? -Good standards plus -capable designers, producers, companies, owners, authorities and testing institutes !