ABSTRACT
The Single European Act of 1985 started the process of forming a European Single Market, intended to remove barriers to free trade across Europe. Prior to this, each country had its own national standards and there was an understandable level of reluctance to accept products and systems tested to the standards of another country.This applied equally to the field of concrete repair, which was a relatively new area of concrete technology and one with a bewildering array of materials used singly or in combination to effect repair and protection. While product datasheets for paints and mortars could be translated from one country to another, the test standards and other ad-hoc tests were often not obviously equivalent in the different countries. A simple example is compressive strength, which in the UK is by crushing a cube specimen, whereas on the Continent, cylinders are commonly used, but at least there are established correlations between the two. For more complex properties, such as the carbon dioxide diffusion resistance of a paint film, methods of test and interpretation varied widely, coupled with many practitioners not understanding the significance of many of the test results that appeared on product data sheets.The situation improved with the development of test procedures by the European Organisation for Technical Approvals (EOTA). In the UK, the British Board of Agrément developed testing procedures for repair mortars and then whole repair systems, which gave the specifier some confidence that an independent party had checked, verified and tested the products to confirm they were following best practice. However, these Certificates were also national, and were based on the national standards and test methods of the originating EOTA organisation. Manufacturers found they often needed EOTA certificates issued for each country in which they were operating.The scope of the Single European Act included the development of a series of ‘New Approach’ Directives. These were to provide a framework for a single market in goods and services, based on a series of supporting technical specifications, or standards. The Construction Products Directives 17 and
18 (European Parliament, 2004) addressed the area of concrete protection and repair and in response CEN, the European standards body, set up Subcommittee TC104/SC8 in 1988 to develop the necessary performance specifications and test methods for the industry.The concrete repair sector in Europe was relatively new in 1988 and few standards applied directly to concrete repair products and systems. The concrete repair sector would therefore provide an ideal route for standards development. Representatives from CEN member countries across Europe nominated technical representatives that could support Steering Committees and Working Groups tasked with drafting the performance standards and test methods that were needed.European Standard EN 1504 ‘Products and systems for the protection and repair of concrete structures’ is the result of this labour, which came into effect on 31 December 2008, taking 20 years to complete. The standard comprises 10 Parts (Table 11.1), six of which are performance standards (Parts 2 to 7) that set minimum performance criteria for repair products and systems to be used for protection and repair of both reinforced and unreinforced concrete.The performance standards cross-reference to nearly 100 new specially developed testing standards for repair products and systems, as well as adopting appropriate existing ISO or national standards (Davies and Robery, 2006). EN 1504 also sets out a methodology for the successful repair and protection of concrete structures, including the supervision and quality control of site works. The end result is a range of products and systems for the protection and repair of concrete that are approved as meeting minimum requirements as ‘fit for purpose’. The vehicle for product approval is the ‘CE-mark’, demonstrating that the product or system meets a particular set of performance requirements.Compliance with EN 1504 will, in effect, be mandatory for many specifiers and purchasers because of the effect of the European Public Purchasing Directives. Government bodies across Europe, including Highways Authorities, have contributed to the development of EN 1504 over the years and have modified their own specifications to bring them into line with the methodology. EN 1504 is therefore highly relevant to the owner, designer, specifier and contractor as well as to the materials supplier.The EN 1504 series and associated test methods were drafted by CEN committee TC104/SC8 and the standards apply across the 25 member countries of the EU as well as Switzerland, Norway and Iceland. 11.2 Structure of the Standard
EN 1504 builds on early work on concrete repair published previously in Europe, including the RILEM Technical Committee on repair strategy (Schiessl, 1994), German guidelines on repair (DAfSTb, 1991), reports by the UK’s Building Research Establishment (BRE, 1997) and various Concrete Society Reports (Concrete Society, various dates), among others. EN 1504
comprises ten Parts, as set out in Table 11.1, with the Parts splitting into the following five sub-groups: • Part 1 provides a series of definitions.• Parts 2 to 7 are the product performance specifications for a variety of repair and maintenance tasks, including protective coatings, repair mortars, plate bonding adhesives and crack injection materials.• Part 8 addresses manufacturer Quality Control systems.• Part 9 provides the general methodology of repair, from initial diagnosis, through selection of the most appropriate repair options for the particular circumstances and client needs, to specification of the minimum performance requirements for specific repair products and systems.• Part 10 covers methodology of site installation for the products and systems, including site testing, supervision and quality control.
