Civil Engineering Reference
In-Depth Information
concrete repair
Peter Robery
11.1 Introduction
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
