4/6/2008
10:49:16 AM 

I just read Lew Migliore's article on fly ash in concrete. Page three of his column "The Commercial Report".

Beware Of Dangerous Situations

 

4/6/2008
11:06:19 AM 

I know that Fritz Tile is actually making SLC and trowelable underlayment and patch material out of fly ash.

If adhesives won't stick to it why would they make it?

4/6/2008
11:28:03 AM 

I read this here the other day what a great read it was. David thank you for working so hard at keeping this industry up to date.

4/7/2008
6:16:24 AM 

Fly ash has been added to concrete to increase the acids that resist Alkali Silica Reaction (ASR) but also results in the concrete being brittle. It increases cracking.

Not taking away anything from Lew here, but these same concrete issues have been with us since "forever" and now it is simply being re-hashed again.

Remember the responsibility of the Concrete Industry:
Pour a slab that meets the strength and density of the specifier.

Additives to concrete have the purpose of increasing strength and/or increasing 30 day strength/density or 60/90 day strength or adding to plasticity (more pumpable)....

Over-use or adding too much Fly Ash to meet strength is the problem.. Fly Ash is cheaper than cement, and competition drives the concrete mix.
Fly Ash does make concrete more pumpable and increases strength but like anything else.. "a little is good and too much is not good".
http://www.flyash.com/

Fly ash is a fine, glass-like powder recovered from gases created by coal-fired electric power generation. U.S. power plants produce millions of tons of fly ash annually, which is usually dumped in landfills. Fly ash is an inexpensive replacement for portland cement used in concrete, while it actually improves strength, segregation, and ease of pumping of the concrete. Fly ash is also used as an ingredient in brick, block, paving, and structural fills.

Fly ash concrete was first used in the U.S. in 1929 for the Hoover Dam, where engineers found that it allowed for less total cement. It is now used across the country. Consisting mostly of silica, alumina and iron, fly ash is a pozzolan--a substance containing aluminous and silicious material that forms cement in the presence of water.
http://www.toolbase.org/Technology-Inventory/Foundations/fly-ash-concrete

4/7/2008
10:48:06 AM 

Let me see if I'm getting this. The use's of fly ash is helping us by getting ridded of waste in our land fields it also help our air and with global worming. It also take less water and less concrete. It also helps with blocking moister and dries cooler so less cracks. It has been used for years with minimal problems.

Now if I'm getting this right the problems come into play because we need more done for the all reasons above. The first problem is at the plants where they are collecting the fly ash. When charcoal is heat up at different tempters at different manufacturing plants some plants are run leaner than others causing slightly different in the fly ash. Then the fly ash is sent out to a manufacturing plant that mix them together this could have infect on the product it self. Making it slightly different than the product that they first started with.

Then there's the demanded factor for more concrete and other things. There could be miscalculation in the rush to get it out to the job sites by concrete manufacturs like software programs or human problems with the mixtures.



I hope I'm not way off base here.

4/7/2008
6:24:13 PM 

So is this installer problem or building owners? I know why not blame the retailer for it. Come on concrete Manufacturers are still charging for it why not finish the job. Bottom line concrete Manufacturers need to make ever effort to inshore there product is up to standers.

4/7/2008
10:10:21 PM 

Ray now I’m confused. I did not think there was a test for fly ash. Fly Ash is a carbon residue material so you're going to have to be extra vigilant and aware of what type of concrete is being used on new builds and involved from the beginning and you got to request the components of the concrete. So are you saying that ph is the way to test for fly ash.

4/7/2008
11:35:48 PM 

The industry a few years back came up with the White Paper that stated it was not the installers responsablity to test the substrate and it was backed by the WFCA but I don't think it ever took hold. I will try and find my copy.

FD

4/7/2008
11:46:15 PM 

http://www.wfca-pro.org/pdf/MoistureWhitePaper.pdf

4/8/2008
12:06:59 AM 

I think Now is the time to start using the White Paper. Tomorrow is to late. http://www.wfca-pro.org/pdf/MoistureWhitePaper.pdf


Any time Roland we are all here for the same reason to share and learn know one knows it all so I keep learning all the knowledge I can.

Thank you all.