ISO/TC 71/SC 7 - Maintenance and repair of concrete structures

This document provides requirements for seismic assessment and retrofit of concrete structures. It can be used to reduce the risk of seismic damage by structural collapse or turnover during a seismic event. This document provides the framework and principles of methods of detailed seismic assessment and the judgment, seismic retrofit plan and design, seismic retrofit execution of existing reinforced concrete structures before the occurrence of a severe earthquake and of the structures struck by an earthquake. It is an umbrella-type document with general provisions intended to provide wide latitude of choice in terms of comprehensive principle on the evaluation of the seismic damage/expected damage of existing reinforced concrete structures and repair/retrofit. Therefore, it is intended to be used in conjunction with sound engineering judgment. This document is applicable to reinforced concrete structures and pre-stressed concrete structures that have been designed on the basis of the structural design criteria set in a specific country or region. It is not applicable to unreinforced concrete and masonry structures.

This document provides a guideline for the selection of a proper grout material to repair water leakage through cracks and other deformities in concrete structures. The factors relevant to the quality control of maintenance and repair of water-leakage cracks are as the following; a) conditions of water-leakage cracks; b) performance requirements for repair materials; c) different types of repair materials (grouts); d) procedures followed to select the appropriate repair materials; e) execution of different types of repair methods; f) performance assessments of applied materials and methods; g) data collection. This document does not include any details on the repair of dry cracks and the causes of cracks. The details on dry crack repair are covered in ISO 16311-4. A flow chart for maintenance of water-leakage cracks is shown in Figure 1.

ISO/TS 16774-6:2017 specifies a laboratory test method for evaluating the substrate (crack) movement response of water-leakage crack repair materials through permeability testing. The repair material injected into a test specimen with an artificial crack undergoes simulated movements normally caused by thermal expansion, settlement and vibrations in leakage cracks found in concrete structures under the applied conditions outlined in different national testing parameters that reflect different environmental conditions. As such, the results are only intended to provide a comparative performance evaluation of the waterproofing repair materials between different products of the same type of repair material. ISO/TS 16774-6:2017 outlines general guidelines and procedures for the test method. Specific variables that control the quantifiable parameters of the testing are filled in using relevant national standardizations and/or testing parameters.

ISO/TS 16774-1:2017 specifies a laboratory test method for evaluating the thermal stress resistance of water-leakage crack repair materials through permeability testing. The repair material injected into a test specimen with an artificial crack is thermally stressed under the applied temperature conditions outlined in different national testing parameters that reflect different environmental conditions. As such, the results are only intended to provide a comparative performance evaluation of the waterproofing repair materials between different products of the same type of repair material. ISO/TS 16774-1:2017 outlines general guidelines and procedures for the test method. Specific variables that control the quantifiable parameters of the testing are filled in using relevant national standardizations and/or testing parameters.

ISO/TS 16774-5:2017 specifies a laboratory test method for evaluating watertightness of water-leakage crack repair materials through permeability testing. These permeability test procedures follow applied conditions outlined in different national testing parameters and requirements. As such, the results are only intended to provide a comparative performance evaluation of the waterproofing repair materials between different products of the same type of repair material. ISO/TS 16774-5:2017 outlines general guidelines and procedures for the test method. Specific variables that control the quantifiable parameters of the testing are filled in using relevant national standardizations and/or testing parameters.

ISO/TS 17774-2:2016 specifies a laboratory test method for the qualitative determination of the retention level of chemical resistance of repair materials in repaired cracks of concrete structures in conditions where the material is either underwater or in contact with water that may have various chemical components present.

ISO/TS 16774-3:2016 specifies a laboratory test method on the quantitative determination of repair material's performance and resistance against erosion and wash out due to underground water flow.

ISO/TS 16774:2016 specifies a laboratory test method for indirectly measuring the adhesion performance of repair material to wet concrete crack surfaces by qualitatively, as a pass/fail at predetermined time, against predetermined amount of weight exerted on the repair material adhesion. NOTE ISO/TS 16774-4:2016 classifies and categorizes materials that are tested into families of similar properties for the purpose of making relative comparisons with the data results.

ISO 16311-4:2014 gives requirements for substrate condition before and during application, including structural stability, storage of materials, the preparation, and application of products and systems for the protection and repair of concrete structures, including quality control and qualifications of personnel, maintenance, health and safety, and the environment.

ISO 16311-1:2014 presents the framework and general principles for maintenance and repair of all kinds of existing concrete structures ? un-reinforced and reinforced concrete, prestressed concrete and steel-concrete composite structures, or their structural members. ISO 16311-1:2014 , deterioration is clearly distinguished from damage occurring in a short period and not developing over subsequent time, such as cracking and scaling due to earthquakes or impact loading, etc. Deterioration is mainly dealt with as a target for the maintenance activities. ISO 16311-1:2014 also provides the basic concept of repair and preventions carried out to restore structural performance of existing structures. ISO 16311-1:2014 does not cover those aspects of maintenance and repair that are related to serviceability and esthetics without direct impact on durability and service life, e.g. cleaning of drains, removal of vegetation, refreshment of paint, etc. Neither does it cover repair of defects during execution of new structures.

16311-3:2014 defines basic considerations and decision-making for the specification of repair and prevention remedies, and management strategies for reinforced and unreinforced concrete structures using products and systems specified in other International Standards or Technical Specifications. 16311-3:2014 covers only atmospherically exposed structures, and buried or submerged structures, if they can be accessed. 16311-3:2014 specifies repair and prevention design principles, and strategies for defects and on-going deterioration including, but not limited to: a) mechanical actions, e.g. impact, overloading, movement caused by settlement, blast, vibration, and seismic actions; b) chemical and biological actions from environments, e.g. sulfate attack, alkali-aggregate reaction; c) physical actions, e.g. freeze?thaw, thermal cracking, moisture movement, salt crystallization, fire, and erosion; d) reinforcement corrosion; e) original construction defects that remained unaddressed from the time of construction. The execution of maintenance and repairs is covered in ISO 16311‑4.

ISO 16311-2:2014 describes general requirements and procedures for the assessment of concrete structures. The assessment can be initiated under the following circumstances, but not limited to: a) an anticipated change in use or extension of design service life; b) structural deterioration due to time-dependent actions such as corrosion of reinforcement, fatigue, etc.; c) safety and/or serviceability check (e.g. for earthquake and increased traffic actions) as required by authorities, insurance companies, owners, etc.; d) structural damage by accidental actions. (See ISO 2394.) This part of ISO 16311 does not cover qualification of personnel, contractual matters, and health and safety requirements for the protection of workers during the investigation and testing.

The purpose of ISO 16711:2015 is to reduce the risk of seismic damage by structural collapse or turnover during a seismic event. It provides frameworks and principles of methods of detailed seismic assessment and the judgment, seismic retrofit plan and design, seismic retrofit execution of existing reinforced concrete structures before the occurrence of a severe earthquake and of the structures struck by an earthquake. It is applicable to reinforced concrete structures and pre-stressed concrete structures that have been designed on the basis of the structural design criteria set in a specific country or region. It is not applicable to either unreinforced concrete or masonry structures.

ISO/TR 16475 gives guidelines for the selection of a proper grout material to repair water leakage through cracks and other discontinuities in concrete structures including the following: conditions of water-leakage cracks; performance requirements for repair materials; different types of repair materials (grouts); procedures followed to select the appropriate repair materials; execution of different types of repair methods; performance assessments of applied materials and methods; data collection.