Building Green with Fly Ash Concrete

Thinking about the Slice House, a marvel in concrete construction, turns my attention toward fly ash. Every once in a while an idea comes along that just makes so much sense you can't believe it. That's the case with fly ash. Fly ash is a byproduct of burning coal to generate power (it's an inorganic material that won't combust and floats out on flue gasses ...). Normally it just gets dumped in a landfill, taking up a lot of space. But here's the upshot. Fly ash can be used in the manufacture of concrete with several important benefits. First of all, you save the landfill space - a lot of space - the equivalent of over a year of household garbage for every ton of fly ash. Secondly, the manufacture of cement for concrete is a very energy consumptive process that emits a lot of carbon dioxide. By using fly ash instead of cement you avoid the energy cost and heavy environmental toll of cement production. Offsetting the need for cement in concrete mixes also saves on cost.

I always though concrete was a pretty good building material. It's very versatile and durable, and actually recyclable to a large degree (it can be reground for use as aggregate in new mixes). Using fly ash only makes it better. The key is to get more fly ash used in concrete mixes. Right now a very small percentage of what is generated each year gets used. Considering how much concrete gets used each year, there is ample opportunity for this plentiful waste product to be put to some good use.

So if you're building your new green dream home, and you want a concrete floor with radiant heat, and some good thermal mass, make sure you use concrete with a high fly ash content. Or go with SCIPs for your walls. There are lots of opportunities to build green with concrete, and fly ash is an important step.

You can learn more at these sites:

Fly Ash Information Center
The Fly Ash Resource Center
Headwaters Resources
Fly Ash Direct
EcoSmart Concrete
Toolbase Services