Greener Concrete from Toxic Ash
[Image Credit: Mikko Itälahti on Flickr under a Creative Commons license]
Fly ash and bottom ash are byproducts from coal-fired power plants. Both are environmental hazards, and their disposal is toxic and costly. Small amounts of these materials can be reused in concrete production, but the rest ends up in landfills or storage lagoons. Georgia Tech assistant professor Mulalo Doyoyo is looking to solve that problem and create a greener, cement-free concrete alternative to boot!
The cement industry is responsible for 5% of the world’s CO2 emissions. Doyoyo’s cement alternative Cenocell, which is created from combining fly ash or bottom ash with organic compounds, is lighter and stronger than conventional concrete with a lower carbon footprint. Cenocell has a number of potential uses from replacing cement and some wood in construction to ultra-light heat sheilding for the aerospace industry.
Not only does this new material keep toxic ash out of the waste stream, Cenocell has strong insulating properties. That means that buildings constructed from Cenocell will be more efficient to heat and cool. They are estimating that it will cost about $50 per cubic yard, which makes it more affordable than concrete, which costs around $75 per cubic yard.
At the moment, they only have small amounts of the material to test. Doyoyo and his research team are working with a Georgia-based maker of autoclaved concrete to produce larger samples for additional testing, though. They are planning to present their findings about the material at the inception workshop of the Resource-Driven Technology Concept Center in South Africa (RETECZA) next week.
This appears to be a very advantageous development. What I don’t see here is an analysis that demonstrates the product is safe for those who live or work in an environment that is using this product. What happens over long periods of time?
Very interesting. Here in the Philippines I just want to know; can we save money to build a house? How much?
Can we use volcanic ash?
It sounds like this is pretty new technology, so these questions are probably still being researched. The issue of safety occurred to me, too…if the components are hazardous waste, how do they ensure that the final product is safe?
I have been living in a new construction home for 16 months. I have been smelling heated chemical vapors and think it is possibly coming from the concrete slab floors or the walls. I have tightness in my chest, have trouble breathing, burning in my chest, dizziness, confusion, heart palpitations, etc. So have my neighbors. What testing should I have done on my home? What chemicals do you think it is?
Hey Robin – That could be any number of things! Maybe you can contact your home inspector, and see what (s)he thinks could be happening? It could be anything from a chemical used in building to a gas leak.
Please be safe!!
Hey. I am currently part of doyoyo’s research team at Georgia Tech and am an undergraduate assistant. This is indeed fairly new research and will be quite revolutionary. Many markets such as China and India are exhausting their resources for producing cement concrete. This is unfortunate however Cenocell will provide a plethora of new concrete that is quite environmentally appealing. As for the health benefits, we have added a biology major to assist us in health tests to maintain standards with the EPA. I hope this clarifies some questions.
P.S. From my view, the final product is safe. It is just a solid block that replicates the look and feel of concrete. Its pretty interesting stuff to say the least. It emits no fumes and is hydrophobic. Unless you eat it, I really do not see any health effects for the final product. However, the process of making it can yield some toxic effects. As I said before, we are researching this.
Hi. My name is Rolan Duvvury and I am also an undergraduate research assistant for Dr. Doyoyo. As Derek said, we are currently researching the effects of heavy metals within the fly ash used to make CENOCELL. The main question is whether the fly ash is sequestrating these potentially toxic heavy metals. My friend Alex MacDougall, who is a fourth year Biology major is currently working on getting EPA approval for the material.
We recently applied a low carbon concrete flooring system in a snack food company in the Philippines. The industrial flooring system is made out of recycled fly ash and slag. Here’s a link: http://resourceefficiency.wordpress.com/2009/08/21/low-carbon-industrial-flooring-site-visit/