Wednesday, November 10, 2010

Are Concrete Countertops Green?

I want an industrial look in my kitchen. I also want to keep it as green as I can. Kitchen Design Plan #25 has me removing the vinyl flooring to expose the concrete slab underneath and building a concrete counter top. Very green, right?

Maybe not.

Before we go any further let’s define concrete and cement:

Concrete I jack hammered out of my flower bed.
Concrete should not be confused with cement because the term cement refers to the material used to bind the aggregate materials of concrete. Concrete is a combination of a cement and aggregate.” 

I’m not sure why concrete is considered a green building material because the rock (generally limestone) has to be mined first and blended with other materials using very high heat before it’s ready to be mixed with water in a cement mixer at your front door to make cement. Often (but not always) to heat these kilns, cement companies use waste materials in addition to burning coal

Is that where concrete gets it’s green street cred? I am not so sure; look at what some (but not all. Local laws and ordinances prohibit the use of some of these materials in some areas but not in others) cement companies use for supplemental fuel:
  • Used tires
  • Hazardous waste (the stuff I drop off at my city’s hazardous waste center or worse? I can’t confirm or deny.)
  • Slaugherhouse waste
  • Plastic waste
  • Sewer sludge
  •  Rice hulls
  • Sugarcane waste
  • Used wood railroad ties
I am all about getting a second reuse out of anything that passes through my hands, but some of the items cause me more concern than others. I know I can’t burn tires as an individual, why can a company? Have you ever seen a tire fire? Tire fires are almost impossible to put out and they give off thick black smoke that cover the sky like the dead of night.

Railroad ties are soaked in creosote and are smoky and nasty to burn. I found this out the hard way when we burned a chunk of railroad tie in a campfire – never again.

I’m doubtful that there are enough scrubbers to line a cement plant smokestack to remove all the potential nastiness they are burning and allowing to billow into the air. In short, I’d hate to live anywhere near a cement plant. Just what is that stuff doing to my lungs and to those around me?

Yet I use this stuff daily. I suspect you do too.

I also don't know of a viable alternative. Do you?

I suppose where the green comes into play is that some companies use waste products from other industries in the cement mix such as slag, fly ash, silica fume, an synthetic gypsum. On the one hand, I wish we had cleaner and more reliable ways to produce goods and materials that didn’t create a need to dispose of their waste products in this way, like the fly ash that eventually lines coal burning smokestacks. On the other hand, I don’t want to give up all of the conveniences that these products offer me either. Remember how much I whined during my last three-day blackout?

Is Concrete a Green Building Material?

Pro

  • Concrete lasts forever. There are concrete structures the Romans built that are still around today.
  • Concrete is one of the few materials that can be gathered, ground down, and remade into concrete. This is typically done in commercial applications. On a smaller scale I found it difficult to find someone who would recycle a consumer’s small amount of concrete after a DIY project.
  • According to an article in the Atlanta Business Chronicle, a Georgia-based company has developed a way to make concrete for less money, that uses half the energy as the current process, and in a way that contains the mercury particles that are released as part of the current cement making process.
  • Concrete is considered green if it is made with a large enough percentage of fly ash. Fly ash comes from burning coal to fuel power plants and ironically the smokestacks from cement plants.
  • A cement building is generally more energy efficient than a wood frame building.
  • In the case of concrete countertops, you can embed other recycled materials in it like glass and use it instead of a slab of mined rock like granite.
 
Con
  • According to Cnet “Cement is one of the worst materials to work with, from an ecological standpoint. It's massively expensive and the manufacturing plants that produce it are some of the world's worst carbon dioxide producers.”
  • According to a report in Forbes, “The manufacturing process also releases large amounts of mercury, which is hazardous to the people who work in the industry.”
  • I’m not exactly thrilled about some of the waste products some cement plants use to power their kilns but I think the alternative would be wood. I’m not exactly thrilled about chopping down trees for that purpose either.
  • Wood is a renewable resource. Limestone, clay, and the other components used to make concrete are not.
  • In the case of countertops, concrete countertops are porous and must be sealed periodically.
  • Concrete countertops are prone to cracking.


What do you think? Concrete has green attributes but also some very nasty ones as well. Is concrete green? Is there a greener alternative?


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This post is part of the Green Mom’s Carnival where our topic is concrete. Be sure to check out all of the posts on our host Retro Housewife Goes Green on November 15, 2010.