The EcoSmart Concrete Project: Minimizing the Greenhouse Gas Signature of Concrete

Michel de Spot chair of the EcoSmart Concrete Project presented this paper at the US Green Buildings -USGBC- in Pittsburgh November 2003.

Concrete a material synonymous with strength and longevity is a leading and universal material that is used in all types of construction. However Portland cement a key constituent of concrete has a significant environmental impact: the making of every tonne of clinker the base for Portland cement produces a similar amount of carbon dioxide -CO2- a greenhouse gas as a by-product which is released into the atmosphere.

The EcoSmart™ Concrete Project’s objective is to minimize the greenhouse gas -GHG- signature of concrete by replacing Portland cement with supplementary cementing materials -SCMs- such as fly ash to the greatest extent possible while maintaining or improving cost constructability and performance. The Project is an innovative industry-government partnership that aims to increase awareness of the benefits and challenges of EcoSmart concrete through case studies applied research and communication to the point where the technology becomes common practice. EcoSmart has demonstrated through a number of case studies that replacement levels of 50% are achievable within the parameters of cost constructability and performance particularly when appropriate design methodologies and construction practices are used.

Implementation of this technology in the field is one of the biggest challenges for EcoSmart. The LEED rating system potentially offers an incentive to specifiers to increase the use of SCMs in development projects. However in order for the LEED system to realize this potential it must first recognize the full environmental benefit of SCMs within its credit system.

Presentation Author: Michel de Spot, P.Eng.

Reducing the Environmental Impact of Concrete

The ability to design and build structures that last for 500 years or more instead of 50 will in the long run increase the concrete industry’s resource productivity by tenfold. Meanwhile substituting recycled materials for natural materials as described in this article it should be possible to substantially improve the resource productivity of the concrete industry immediately. Unquestionably the greatest challenge that the concrete industry faces during the 21st century is to achieve a sustainable pattern of growth. The task is formidable but the ideas and examples cited in this article show that it can be accomplished provided we make a paradigm shift from the culture of accelerating construction speeds to a culture of conservation of energy and material.

Technical Report Author: P. K. Mehta

Concrete Technology for Sustainable Development

In this article the author identifies what he sees as essential elements that are crucial to lay the foundation upon which the structure of an environmentally-friendly concrete technology can be built. The three essential elements of the foundation are: conservation of concrete making materials enhancement of durability of concrete structures and a paradigm shift from a reductionistic to a holistic approach in concrete technology research and education. Mehta argues that sustainable development for the cement and concrete industries can be reached if we make an effort to use the cementitious and pozzolanic byproducts produced by power plants and mettallurgical industries. Further concrete mixtures containing slag or fly ash are less prone to cracking and have increased structural durability through prolonged watertightness through service life.

Technical Report Author: P. K. Mehta

Greening of the Concrete Industry for Sustainable Development

The concrete industry is energy intensive and produces a large volume of carbon dioxide emissions. To reduce the environmental impact of the industry we must practice industrial ecology by recycling the waste products of one industry by substituting them for the raw materials of another. Blended portland cements containing fly ash from coal-fired power plants and ground granulated slag from the blast-furnace iron industry provide excellent examples of industrial ecology because they offer a holistic solution for reducing the environmental impact of several industries. High speed construction building codes that are prescriptive rather than performance based and the lack of a holisitic approach in engineering research and education lead to the construction of concrete structures with cracking and durability problems. Greening of the concrete construction industry will have to proceed before green concrete replaces conventional concrete as the material of choice for general construction.

Technical Report Author: P. K. Mehta

Advancements in Concrete Technology

In terms of advancements in concrete technology the driving forces have been durability and speed of construction. However the environmental impact of construction materials is becoming an increasingly important driver. In this paper Mehta evaluates concrete technologies using the criteria of construction speed durability and environmental impact. One of the technologies he examines is high volume fly ash and slag concrete particularly in terms of their use in structural concretes roller compacted concrete dams concrete pavement for highways and base courses and embankments.

Technical Report Author: P. K. Mehta