All about Concrete
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Glossary

A

Absolute/specific CO2 emmissions

Absolute CO2 emissions are the total volume of CO2 emitted, while specific emissions are relative and proportionate to a given amount of production. A specific quantity of CO2 is emitted for every 1 ton of cement, for example.

Aggregates

Aggregates are small rock fragments (0.08 to 80 mm) of mineral origin. Aggregates come in different types: maritime, fluvial and terrestrial. They may be sand, gravel or crushed gravel. Aggregates, mixed with water and cement, are essential for the production of concrete.

B

Bauxite

Bauxite is an aluminum ore. It is named after the village of Baux-de-Provence, France, where it was discovered.

Biodiversity

Biodiversity refers to the diversity of living organisms and species in land, marine and aquatic ecosystems.

Biomass

Biomass refers to any organic material derived from plants that can be used to provide energy. It is the biodegradable portion of:

  • by-products, wast and residues from agriculture, forestry and associated industries
  • industrial plant waste and residues

C

CO2

Carbon dioxide (CO2) is a greenhouse gas. It is produced by the combustion of organic compounds and the respiratory systems of animals and plants.

The cement industry naturally emits CO2:

  • 60% of emissions are due to the physical-chemical transformation of raw materials at high temperatures
  • 40% result from the combustion needed to heat the cement furnace to 1500°C
CO2 quotas

Greenhouse gas emissions quotas and the emissions quotas trading system (EU-ETS scheme) were established by a European directive in 2003.

Revised in December 2008, the directive aims to clarify the conditions for implementation of it's target to reduce CO2 emissions in EU (European union) countries by 20% between 1990 and 2020. The new directive therefore regulates CO2 emissions in EU countries for various industrial sectors (the cement, steel and paper industries, for example).

This mechanism, which applies for the 2013 - 2020 period:

  • determines annually a quantified limit on emissions for each company (1 quote = 1 ton of CO2)
  • defines selection criteria for sectors most at risk of "Carbon leakage" as a result of inflated costs in relation to CO2, which could see their competitiveness adversely affected by countries outside the EU which have not made comparable commitments,
  • grants companies with a surplus of quotas the ability to sell emissions rights to companies with a shortage of quotas.
Carbon leakage

Replacing local production in a market with carbon restrictions with production from an area without carbon restrictions due to the cost of CO2 not being taken into account. Carbon leakage, defined in this way, does not lead to reductions in CO2 emissions and even increases them due to the transport generated, destroys economic value and has a negative social impact in terms of jobs on the market with carbon restrictions.

Cement

Cement is a hydraulic bonding agent which is obtained by heating, then grinding, a mixture of limestone and clay. Most cements are made from clinker and additives and are usually used in the form of a powder. Cement sets when mixed with water. Combined with sand and aggregates (sand or gravel), it turns into rock-hard concrete or mortar.

Cementitious

Called "cement additives", these minerals are used in varying proportions during the last phase of the cement production process. The additives make it possible to obtain a range of cements with different properties. They can be:

  • of natural origin, for example limestone or volcanic or sedimentary rock (pozzolanic rock),
  • of industrial origin, for example byproduct of the steel industry (slag from blast furnaces)

The use of cementitious additives reduces CO2 emissions:

  • firstly, because using additives in cement production automatically reduces the proportion of clinker (the decarbonation phase of clinker production releases a lot of CO2),
  • secondly, because it uses industrial waste which would otherwise have been discarded and treated by the local authority

 

Clean Development Mechanisms (CDM)

The Kyoto Protocol does not set limitations on CO2 emissions for developing countries but it does encourage the adoption of alternative mechanisms.

Companies which finance CO2 emission reduction projects in developing countries are compensated with carbon credits.

CDM's are designed to promote the development of better technologies in emerging economies while enabling industrialised countries to earn carbon credits.

Climate change

The term "climate change" refers to meteorological and temperature modifications observed over the course of the last century. It is attributed to an increase in the concentration of greenhouse gases, such as carbon dioxide (CO2) and methane, in the atmosphere. These gases trap solar energy in the atmosphere, warming the land and the oceans.

According to the Intergovermental Panel on Climate Change (IPCC), 90% of the increase in the concentration of these gases is due to human activities and only 10% is due to natural causes.

Clinker

Clinker is the main ingredient in cement. These hardened granules are obtained by firing a mixture of approximately 80% limestone and 20% clay to a high temperature. Cement is obtained by grinding clinker and, in some cases, supplementing it with additives.

Co-incineration

Co-incineration uses waste as an alternative fuel. In this way, waste from one industry becomes fuel for another.

Concrete

Concrete is a building material made by mixing water, aggregates and sand with a binding agent (usually cement) and, if necessary, with additives. This mixture is made on building sites and factories.

 

The characteristics of a concrete can vary greatly depending on the choice of cement and cement-aggregate ratio, the type of aggregate used, the inclusion of additives, etc. The way concretes are used and surface treated can also have an impact on their performance and appearance. So concrete is reconstituted stone and is sometimes referred to as "liquid stone".

E

EU-ETS scheme

Greenhouse gas emissions quotas and the emissions quotas trading system (EU-ETS scheme) were established by a European directive in 2003.

Revised in December 2008, the directive aims to clarify the conditions for implementation of its target to reduce CO2 emissions in EU (European Union) countries by 20% between 1990 and 2020. The new directive therefore regulates CO2 emissions in EU countries for various industrial sectors (the cement, steel and paper industries, for example).

This mechanism, which applies for the 2013 - 2020 period:

  • determines annually a quantified limit on emission for each company (1 quota = 1 ton of CO2),
  • defines selection criteria for sectors most at risk of "carbon leakage" as a result of inflated costs in relation to CO2, which could see their competitiveness adversely affected by countries outside the EU which have not made comparable commitments,
  • grants companies with a surplus of quotas the ability to sell emissions rights to companies with a shortage of quotas.

F

Fly ash

Fly ash is hydropholic and can be used as a cementitious additive. The ash, which is collected from chimney filters in coal-fired power plants, is composed of vitreous silica, alumina, iron oxide and lime.

 

They can be used as a partial substitute for clinker and thus help to reduce CO2 emissions.

G

Geothermal heat pump

A geothermal heat pump takes advantage of the natural warmth of the ground below the frost line to heat spaces about ground, even though thermodynamic principles should result in this warmth being diffused when it comes into contact with cooler elements.

Governance

Governance is the set of rules (both legislative and internal) which determine the way a company conducts its business. Governance is designed to guarantee transparency, oversight and ethics in business.

Gypsum

Gypsum is a construction material made by firing the gypsum mineral in a kiln and then grinding it. It can be used as a paste or as pre-fabricated boards. Mixed with water, it forms a gel that sets within a few minutes and then hardens. It is widely used for interiors: coatings, dry partitions, ceilings and wall linings in the form of tiles or plasterboard. It has several important properties: acoustic and thermal insulation, fire resistance, etc.

I

Industrial waste

Industrial waste is the residue from production, processing or use. Waste products from other industries are used both as alternative fuels and as substitute materials. Co-incinerations enable enterprises to economize fossil fuels and raw materials while serving the community by processing waste in an economical way that reduces CO2 emissions.

Injury frequency rate

The lost-time injury frequency rate is the number of accidents leading to loss of time, by million hours worked.

International Labour Organisation (ILO)

The ILO is a United-Nations agency which brings together governments, employees and workers. Its purpose is to promote decent working conditions throughout the world to ensure employees benefit from liberty, equality, safety and dignity. Its actions encourage the creation of decent jobs and the development of social protection and dialogue.

K

Kyoto Protocol

The Kyoto Protocol aims to reduce greenhouse gas emissions on a global scale. The principle is based on varying levels of commitments for different governments. Industrialized countries have made stabilization or reduction commitments which correspond on average to a 5% reduction in their emissions for the period 2008/2012 compared with 1990. Developing countries are under no obligation but are encouraged to develop CO2 emissions reduction programs which can be used to generate credits: that is the principle of the "Clean Development Mechanism" (CDM) which involved promoting efforts in emerging countries.

L

Life Cycle Assessment (LCA)


A building's Life Cycle Assessment (LCA) quantifies its environmental impact according to several criteria:

 

  • primary energy consumption,
  • greenhouse gas emissions,
  • air pollution,
  • water consumption,
  • transport,
  • waste production,
  • a material's lifecycle (from extraction to recycling or landfilling)

LCA is now part of the Group's research methods. A truly scientific approach, this objective analysis uses a standardised methodology (ISO 14040) and questions many concepts taken for granted in construction.

N

Net/Gross emissions of CO2

Net emissions of CO2 are equal to the gross emissions minus emissions related to the burning of waste.

P

Photovoltaic cell

A photovoltaic cell is an electronic component which generates electrical tension (or voltage) when exposed to light and can therefore be used to produce electricity. These cells produce a constant current with an average voltage of 0.5V.

Plasterboard

Plasterboard panels are industrial building components. They are made in factories by locking a thin layer of gypsum and additives between two cardboard sheets to create thin panels. Plasterboard is put in place with screws or adhesive mortar. The panels can also be nailed or screwed to wooden or metal frames to dress interior walls and partitions.

Pozzolan

Pozzolan is named after Pozzouli, a region near Naples, Italy, which is rich in volcanic ash.

 

Natural pozzolan is a light siliceous mineral produced during basaltic volcanic eruptions. It contains silica, alumina and iron oxide (which gives it a red colour), as well as lime and magnesium oxide. Pozzolan is used as a cement additive.

 

Artificial pozzolans with the same properties as natural pozzolans can be created by heating clays, basalts or schists.  

Purcahse/Sale of CO2 quotas

In the context of the European Union Emission Trading Scheme (EU-ETS scheme), CO2 quotas can be exchanged by companies:

  • by mutual agreement between 2 companies which negotiate the price,
  • or on one of the "carbon exchanges" set up in Europe

S

Slag

This mixture of lime, alumina and silica is produced when iron is smelted with coke in blast furnaces in the steel industry. Slag accumulates on top of the molten cast iron. If cooled quickly, its hydraulic properties are close to those of clinker. Slag takes longer to hydrate but it offers greater stability in corrosive conditions. It is, therefore, a suitable additive for cement and concrete so as to reduce CO2 emissions.

Social business

Social businesses use an economic model which is both financially profitable and socially responsible. The goods and services they offer provide an innovative and practical solution to social and environmental problems such as malnutrition, access to housing and waste management.

Sustainable construction


Sustainable construction aims to limit the impact of buildings on the environment while enhancing their quality in terms of aesthetics, sustainability, durability and strength. Sustainable construction techniques apply across the entire lifecycle of a building, from the selection of initial materials to demolition and recycling.

 

Sustainable construction signifies in particular:

  • the use of recyclable materials to conserve natural resources,
  • the integration of renewable energy sources into a building's design,
  • the optimization of renewable energy sources
Sustainable development

The World Commission on Environment and Development defines sustainable development as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs".

 

Sustainable development aims to reconcile 3 major stakes:

  • economic performance
  • the social consequences of a company's actions (with regard to employees, suppliers, customers and the local community),
  • environmental aspects (achieving a balance between a company's activities and the preservation of ecosystems).

T

Thermal bridge breaker

Element designed to reduce heat loss caused by thermal bridges. It may be made from polystyrene containing steel reinforcement or concrete, for example.

Thermal inertia

This term designates the ability of a material to accumulate and store calorific energy which can then be released over a period of time.

U

United Nations Environment Program (UNEP)

The U.N.E.P, created in 1972, is the highest environmental authority of the United Nations. The UNEP works with United Nations agencies, international governmental and nongovernmental organizations, the private sector and civil society. The UNEP has set up the Sustainable Buildings and Construction Initiative (SBCI), of which Lafarge is a member and former chair.

W

Water footprint

The water footprint concept uses a single indicator covering every stage in a product's lifecycle to assess the quantity of water taken in (water network, rivers, drilling, etc) against the quantity and quality of water discharged.

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