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Second only to water Cementing good environmental practices for concrete

by Prof. Koji Sakai, Chair of ISO/TC 71/SC 8, Environmental management for concrete and concrete structures

Concrete is essential to the creation of the infrastructure and buildings that form the basis of human socio-economic activity. It is an extremely sim-ple material consisting of aggregate, cement, water and admixtures, materials that are naturally found in great abundance one of the main reasons why concrete is such an important construction material.

However, the quality of concrete is not always easy to maintain, as it is the result of a chemical reaction between cement (itself a product of the high-tem-perature combustion of limestone and clay) and water. The aggregate (sand and gravel), which makes up 70 % of the volume may be of uneven quality, and as concrete is produced in facto-ries before being transported as a semi- finished product to construction sites, quality control may be limited.

Global production of cement in 2007 was 2,77 billion tons. From this, the current annual production of con-crete is estimated to be approximate-ly 15 billion tons (although no precise

ISO Focus October 2008 23

Main Focus

About the author

Koji Sakai is a professor of Kagawa Univer-sity, Japan. He chairs ISO/TC 71/SC 8, Environmental management for concrete and concrete struc-tures, and the

International Federation for Structural Concrete (fib) Commission 3 on envi-ronmental aspects of design and con-struction, and the Japan Concrete Insti-tute Committee on minimization of global warming substances and wastes in the concrete sector.

statistical data are available), making it the second-most used material on the Earth after water.

The environmental impacts related to concrete are considerable. In cement production, large amounts of carbon dioxide are emitted from the materials compound elements and fuel sources. The transportation of these compound elements and concrete products also con-sumes large amounts of energy, gener-ating still more carbon emissions and other pollution.

agement, include ones that provide basic requirements for environmental product labels and declarations, and for carrying out lifecycle assessments.

In a similar vein, and follow-ing on this lead, ISO/TC 59, Building construction, SC 14, Design life, and SC 17, Sustainability in building con-struction, have respectively developed ISO 15686-6, Buildings and construct-ed assets Service life planning Part 6: Procedures for considering environmen-tal impacts, and ISO 21930, Sustainabil-ity in building construction Environ-mental declaration of building products (see page 11).

A solid approachISO 15686-6 presents procedures

for the assessment of environmental impacts, while ISO 21930 provides rules for the implementation of environmental declarations for building products. The concrete sector realized their value, par-ticularly given the industrys consider-able use of resources and energy. It was clear however, that the sector needed to develop their own environmental stand-ards, in order to ensure that these would apply to the practicalities of this specific industry. The aim was thus to assess the environmental impacts caused by con-struction projects and to work continu-ously towards their reduction.

ISO/TC 71, Concrete, reinforced concrete, and pre-stressed concrete ; thus decided to establish subcommittee SC 8, Environmental management for concrete and concrete structures (EMCC). The subcommittee was approved by ISO in February 2008 and its first meeting was held in Los Angeles, USA in March 2008, where it was agreed to develop standards on the following topics :

general principles ; preparation of inventory data and sys-

tem boundaries ; constituents and concrete production ; environmental design of concrete struc-

tures ;

execution of concrete structures ; operation of concrete structures ; end-of-life phase including recycling

of concrete structures ; labels and declarations.

Production of concrete is expect-ed to increase several-fold in the future. Considering the unlikelihood of any new construction material emerging to replace it, the construction sector must ascertain the extent of the environmen-tal impacts it poses and develop tech-nologies to reduce these.

ISO has already produced the ISO 14000 family, which is one of the most widely used series of environmental man-agement standards. The standards, devel-oped by ISO/TC 207, Environmental man-

Concrete is essential to the creation of the

infrastructure and buildings that form the basis of human socioeconomic

activity.

The standards will provide a plat-form and a set of common rules for the evaluation of environmental impacts and benefits of concrete and concrete structures in an objective and transpar-ent manner. Existing ISO environmen-tal standards will naturally provide the basis of these EMCC standards.

Concrete is the second-most used material

on the Earth after water.

24 ISO Focus October 2008