The key raw material in cement is limestone, a natural resource that can be found in abundance in most regions globally. Quarrying of limestone is the first stage in the process of cement production. In the cement industry, as in most major industrial sectors, natural resources are a core part of the final product. The question is how sustainably the industry can extract these resources.
CSI members have been actively applying sustainability concepts to their quarrying activities, through undertaking Environmental and Social Impact Assessments (ESIA) at new sites, implementing quarry rehabilitation plans, and consulting with local communities to best meet their needs. Dust and noise impacts from quarrying activities have been reduced through new quarrying techniques, and communities also reap important benefits from increased employment and investment in local amenities.
The CSI believes in a life-cycle approach to cement production. Quarrying extracts virgin aggregate from the earth, but increasing use of recycled concrete as aggregate has helped to reduce demand for virgin aggregate.
The cement industry produces about 2.6 billion tonnes of cement annually. The most important use of cement is in the production of concrete, twice the amount of which is used than the total of all other building materials, to construct our homes, schools, hospitals, sewage systems, pavements and more. Concrete is the most used used man-made material in the world, a fact not widely known. Concrete has a cement content of between 10-15%.
Cement is made by heating limestone with small quantities of other materials (such as clay) to about 1450 ˚C in a kiln. The resulting hard substance, called "clinker", is then ground with a small amount of gypsum into a powder to make ˜Ordinary Portland Cement", the most commonly used type of cement (often referred to as OPC).
With modern and innovative technologies, the cement production process has become more eco-efficient over time. Increased usage of alternative waste fuels (providing a novel and key waste management option), clinker substitutes (such as slag and fly-ash), and energy efficiency improvements have all reduced the industry's CO2 emissions. Half of all CO2 emissions from cement production originate from the basic calcination process the heating of limestone to form lime. 40% comes from usage of fuel, and the remaining 10% from electricity usage and transportation.
Transportation accounts for a minor percentage of CO2 emissions from the cement sector. Raw materials are transported from quarries to cement plants, and the final cement product is then transported to customers.
Cement plants are in general located short distances from both their quarries and customers. In short, cement is often a locally used product, in order to minimize expensive bulk transport of the raw materials and cement. The relative expense of land transport usually limits cement sales to within 300km of a plant site. At present very little cement is traded and transported internationally.
The built environment
Cement is the bond that literally holds today's infrastructure together, whether it is an individual home in Mexico, or a 5th runway at Heathrow. Concrete is the most widely used material on earth apart from water, with nearly three tons used annually for each man, woman and child.
It is easy to overlook the use of concrete in society. Concrete plays a vital part in our daily lives and in a functioning society. Its benefits to society are immense, being used to build our schools, hospitals, apartment blocks, bridges, tunnels, dams, sewerage systems, pavements, runways, roads and more. Many of these could not be built without concrete.
Twice as much concrete is used around the world than the total of all other building materials, including wood, steel, plastic and aluminium. None of these other materials can replace concrete in terms of effectiveness, price and performance for most purposes.
Concrete, with its strength, durability and excellent thermal mass, should be a key component in eco-buildings of today and the future. In May 2008, The Guardian in the United Kingdom featured the first zero-carbon house developed by a volume housebuilder, in which concrete plays a critical role in maintaining internal temperatures.
In the 2002 Agenda for Action the CSI's blueprint outlining a pathway toward a more sustainable cement sector, CSI members affirmed their unified commitment to embarking on a systematic, proactive effort to improve their environmental and social impacts. Five critical sustainability work areas were identified back then, and addiitional issues were added through the years. Notable measures have been made taken across all the work areas to set a platform for deeper and more extensive sustainability improvements.
|CO2 and Climate Protection||Responsible Use of Fuels and Raw Materials||Employee Health and Safety||Emissions Monitoring and Reduction|
|Local Impacts on Land and Communities||Water impact management||Sustainability with Concrete|
|CO2 and Climate Protection||Responsible Use of Fuels and Raw Materials|
|Employee Health and Safety||Emissions Monitoring and Reduction|
|Local Impacts on Land and Communities||Water impact management|
|Sustainability with Concrete|
Regular progress reports are presented with the most recent one being the 2012 Progress Report.