The only materials I will avoid are batches from gas stations and other polluted sites.
Morgan Morrigan wrote: There is a new "green" concrete that uses less than 10% of the energy to make. Uses mining slag instead of ash and clinkers.
We purchased them at Lowe's and Home Depot and both called them concrete blocks. I've just always referred to them as cinder blocks. I didn't know there was a difference.
Stone and brick are often coated in lime mortar. I have cleaned both for re-sale by mixing them with maple leaves. The acids in the leaves work on the lime. A year later I have clean brick and stone and improved soil. It's a huge labour saver.
kent smith wrote:cinder blocks were made from volcanic cinders, not cinders for coal burning. Fly ash a by product from burning coal is a common additive to most concrete. It has some cement like properties as in is does set up like cement and it is a cheap filler.
Ken Peavey wrote:Concrete and mortars used in industrial settings are another story altogether.
kent smith wrote:Jonathon, as a past front range resident, I would think that using concrete is less of a toxicity issue than other things in the front range. Each time I would drive down I-70 from my past home on squaw pass into denver to work I would see the heavy brown cloud as drove down into it.
M Marx wrote:some of the furnaces used in making concrete burn things like tires, medical waste, and toxic waste -- things the epa won't let normal incinerators burn b/c they are too toxic. So, while it may not be toxic in the concrete, it seems making concrete is probably not a good long term plan in it's current form.
Puddnhead McCoy wrote:I was thinking of putting in some permanent two-foot-high raised beds near my house and was planning to use brick over a concrete footer. Reading through this thread, it seems that the jury is still out on concrete. Just curious if anyone has any suggestions for an alternative way of building a permanent (and attractive) raised bed.