permaculture

[McFarlandAIA@aol.com]

Concrete,

Concrete is a generally a wonderful product. It is fluid and flexible when 
poured and solid when it has cured. The materials that comprise concrete are 
sand, water, rock and cement. The first three materials can be mined locally, 
thus reducing transportation costs. Chemical admixture must be kept to a 
minimum. 
The use of Portand Cement can be eliminated by substituting fly ash, a 
byproduct of coal burning power plants (as long as it has no radioactive 
content). 
Here in Texas, there is a local source for fly ash. Thus, concrete, used in 
this manner, can have a low environmental impact and is a very durable and 
long-lasting material.

Shawn McFarland, AIA, LEED AP
Permaculture Guild of Houston