Why Concrete?

Concrete is the most widely used construction material on earth.  In many developed countries, concrete infrastructure comprises about 60% of the built environment.*

Concrete has shaped civilizations from as far back as Ancient Egypt and the Roman Empire. 

Today, it is indispensable in the development of infrastructure, industry and housing.  Without concrete, the built environment would fail to accommodate our modern and demanding lifestyles.  Given our reliance on concrete, it will inevitably play a major role in New Zealand’s ability to pursue sustainable development.

The importance of sustainable development is currently dominating headlines, and as a concept is frequently defined as the practice of meeting present needs without compromising the ability of future generations to meet their own needs.

The quest for sustainability has been compared with New Zealand’s nuclear free stance in the 1980s, and politicians have been enthusiastically pledging their support to make New Zealand the “first nation to be truly sustainable”.**  There is no question that sustainable development has been adopted as the philosophy to direct New Zealand’s way forward, and as a means to find solutions that provide the best economic, social and environmental outcomes.

Produced from readily available raw materials, concrete’s strength, durability and versatility ensure it provides solutions for the built environment that help achieve sustainable development. 

At its most basic, concrete is a mixture of aggregates and paste.  The aggregates are sand and gravel or crushed stone; the paste is water and Portland cement.  Portland cement is the generic term for the type of cement used in virtually all concrete.  Cement comprises from 10 to 15% of the concrete mix, by volume.  Through a process called hydration, the cement and water harden and bind the aggregates into a rock-like mass. With appropriate mix design, concrete can be tailored for any construction requirement.

As outlined in the following sections, major efficiencies and innovations in the manufacture of cement and the production of concrete have been achieved over the past decades, while the CO2 absorption capabilities of concrete are beginning to be fully understood.  The reuse of concrete structural elements is becoming more commonplace, along with the recycling of concrete as aggregate.  Furthermore, concrete’s durability, thermal efficiency, acoustic performance, fire resistance, and roading and stormwater management applications, will ensure that its contribution to a sustainable New Zealand construction industry continues to be significant.

This website seeks to demonstrate how concrete contributes to both this and future generations’ sustainable development, and will be of interest to architects, engineers, policy makers, contractors and clients, as well as others involved with the design, construction or operation of buildings and infrastructure.

*Mak, S.L. (1999). Sustainable use of concrete through carbon abatement and sequestration. Proceedings of the Int. Power & Energy Conf., Churchill, Victoria, Australia, 1999.

**Rt. Hon Helen Clark. Speech notes for address to Buddle Findlay Sustainability Seminar. Wellington. (8/05/2007). Retrieved August 2007 from http://www.beehive.govt.nz/ViewDocument.aspx?DocumentID=29235