Introduction Of all the construction materials that shape our world, concrete is the most versatile, economical and widely used. It has long been an indispensable component of the economic and social growth of developed and developing countries alike. In some applications, concrete performs its task unseen below ground, or clad and covered by other materials. In others, like civil engineering works, hard landscaping, architectural cladding and masonry, it is highly visible.

Few people realize its contribution to the infrastructure and built environment and public attitudes have sometimes been influenced by occasional abuses of the very properties which make concrete such a uniquely valuable construction material

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Concrete in Buildings

Concrete is an environmentally friendly material for building projects and has qualities that make it the designer's material of choice. Concrete offers excellent sound and fire protection as well as high thermal mass. Eco-designers believe that the way to sustainable building lies in long-life, adaptable, low-energy design. The earth's resources are best conserved if the service life of the building is prolonged, so the durability and longevity of concrete make it an ideal choice.

Designing out maintenance and repair, and designing in flexibility for change of utilization can also extend service life. Concrete construction offers designers a better long-term means of achieving these design objectives.

Specialist techniques such as pre stressing make it possible to use less material and to create the longer spans that require fewer support columns and lead to enhanced flexibility of buildings in use

Concrete has excellent fire resistance properties: it is non-combustible and has a very slow rate of heat transfer. Unlike some materials, even the hottest fire will not cause it to release any harmful emissions. Thus concrete buildings provide safe and reliable protection from the dangers of fire.

The material is also effective at protecting against noise. With the current pressures of densification that lead to more compact cities and denser developments, concrete is an ideal material to reduce noise pollution. Concrete walls and floor are particularly good at:

* Reducing airborne sounds like traffic noise

* Reducing vibration from plant and equipment

o Insulating against conversation and music

The thermal capacity of concrete (sometimes called thermal mass) enables it to absorb, store and later radiate heat. It absorbs the heat created by people, computers, lighting, equipment and solar gain, thereby reducing daytime temperatures especially in commercial buildings and facilitating savings in air conditioning.

Concrete in the Built Environment

A concrete road has excellent durability, stability and rigidity, and in many countries is the preferred form of construction to provide long-term structural performance for heavily trafficked roads.

Because concrete does not rut under heavy traffic loads, it provides a surface that extends the period before disruptive maintenance work becomes necessary.

Concrete is a safe and inert material for storing and transporting water. It does not contribute any environmentally threatening chemicals to water.

It is also used in applications such as flood protection and erosion control. Permeable concrete paving, now growing in popularity, even allows infiltration of rainwater into the soil to help reduce run-off in urban areas.

Concrete continues to be used in the construction of essential elements of infrastructure for water supply, sewage treatment and waste disposal, including:

* Pipelines and tunnels

* Pumping stations

* Treatment basins and holding tanks

* Dams and reservoirs

* Water towers

* Waste containment basins

As long as people remain at risk from hazards such as fires, explosions, spillages, flooding, and earthquakes, concrete has an important role to play in offering protection to life and property.

For over 2 000 years, concrete in its various forms has provided civilizations around the world with unrivalled strength, durability and reliability. Its long and extensive usage indicates that these qualities are fully understood and appreciated by engineers, architects and scientists.

It is, however, also a material that brings many benefits to those working to conserve scarce resources and limit the environmental impact of construction.

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Sources Consulted

British Cement Association, Concrete in the environment, Crowthorne: BCA, 1993. (INF 111-0193)

British Cement Association, Ecoconcrete, Crowthorne: BCA, 2001. (97.381)