I'm at a loss . . . .

[BigH]

Colleagues:

Thought I would try out our group here. As I indicated, I am at a loss on the subject.

Problem:
1. Subcontractor is bagging fly ash in used 1 tonne bags.
2. Bags previously contained chemicals and we are unsure as to the "purity" of the bags before placing the fly ash into them.
3. Names of the chemicals - that we can surmise at present:
a. Phthalic Anhydride
b. Terephthalic Acid
c. Polyethylene Terephthalate
d. Polyamide 6

Questions:
i. Does any of the above chemicals react adversely with the fly ash? with mix water?
ii. Does any of the above chemical react adversely with fresh concrete?
iii. If so, for the above, at what levels of contamination?
iv. Any long term affects? e.g., expansive effects on aggregates?

Notwithstanding the above, I am leaning to recommending rejection of the fly ash as the bags are not even labeled with respect what they contain - is it really fly ash? No mention as to which source. An ISO 9000 certified company appears to miss the mark on the rudiments of labeling. However, as one knows, politics to get the job done sometimes over-rules such actions. So, any thoughts? Would any of you know a network contact who might be able to give a thought?

Location and project - on the QT.

Thanks for any thoughts . . . (Ron, Iandig, ??)

 

[Ron]

BigH...yes, those are organic polymers and can react with concrete...most likely slowing or possibly stopping hydration as most organic contaminant will do.

Phthalates are kind of nasty...they will contaminate water as well.

Mixing with fly ash, depending on the fly ash source, could cause some cross polymerization resulting in some odd polymer, though I'm not smart enough to tell you what that would be!

All of those chemicals are used in plastics and epoxies.

Not sure what levels or concentrations of those it would take to cause an issue, but wouldn't want any of it my concrete or water.

 

[BigH]

Thanks Ron - goes with what I and one of our area supervisors (working in concrete since 1965) think - if you don't know what the effect is, don't use. But, money - brought to site on spec.

 

[iandig]

I have also posed this to a good contact of mine. There specilaise in concrete and concrete attack, and led most of the research in the UK on concrete attack, sulfates etc... No news yet but I have attached a link to hteir web-site below:

http://www.geomaterials.co.uk/

 

[jheidt2543]

BigH:

I submitted your question to ACI in hopes that one of their committiees might be able to shed some light on it. However, it may take a while to get a response.

I can't help but wonder, why bag the flyash? Why not just send it up in bulk trucks, even dump trucks?

 

[BigH]

Jim - Big trucks don't travel well on water! Shipping from Java to Sulawesi (old Celebes). Besides the chemicals, this is going to be a "grey hair inducer" problem . . .