 Concrete is one of the main materials used in buildings that earn LEED certifications- The primary ingredients of concrete—crushed stone or gravel, sand and water—account for approximately 90% of the mixture and are plentiful in most locations- Cement, which accounts for most of the rest of the mixture, is usually produced and available regionally as well- Therefore, EnviroCitizen.org has leraned that cement is good because it is produced locally, reducing transportation- In addition, as a made-to-order material, concrete construction results in less building waste.
Like any manufacturing process, the production of cement used in concrete results in the creation of greenhouse gases, but the U.S. cement industry has reduced carbon emissions by 30% since 1972 and now accounts for only 1.5% of U.S. emissions. The carbon embodied in concrete as a finished building product is a very small quantity considering that cement accounts for a small proportion of the finished product- The other good news about cement is that it is being made from better materials for the planet.
The concrete industry is beginning to use industrial waste byproducts such as fly ash (from coal combustion) and blast furnace slag (created in iron manufacture) to constitute a portion of the cement used in producing concrete- Another new concrete has been spotted which consists of titanium dioxide, a compound that becomes chemically active in sunlight, called TX Active cement. It effectively neutralizes air pollutants such as benzene, carbon monoxide, nitrogen oxide, etc- Use of such byproducts in concrete prevents 15 million metric tons a year of these waste materials from entering landfills- Utilizing these cementing materials as a replacement for conventional cement improves the strength and durability of concrete and also further reduces the carbon emissions in the production of concrete by as much as 70%- These are the ingredients that are creating the new, green concretes.
When a concrete structure has served its purpose, it can be crushed for use as aggregate in new concrete or as fill or base materials for roads, sidewalks and concrete slabs- Even the reinforcing steel in concrete (which often is made from recycled materials) can be recycled and reused.
When rebuilding, concrete can be a great material to use- EnviroCitizen.org cautions you to be sure to contact various dealers and find out how their cement is produced to make a sustainable choice- Many are offering the new green cements that are discussed here as well as other new options that are better for the Earth.
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