Use of Waste Foundry Sand in concrete 2

[AaronS]

Looking for someone who may have some knowledge using foundry sand in concrete or asphalt. Looking for the good and bad using the product.

 

[Ron]

DO NOT USE FOUNDRY SAND IN CONCRETE!!!! Foundry sands often contain unreacted magnesium oxide (periclase) or unreacted free lime which can cause significant expansion in the presence of water. The results can be similar to using electric arc steel slag in concrete. Not good! Don't even use it for fill.

Be careful when using it as filler or fine aggregate in asphaltic concrete mixes. In sufficient quantity, it can still react and cause some expansion. At the least it might result in "bulking" of the asphalt which will allow more water permeance and subsequent failure. [sig][/sig]

 

[redlabel]

how about using crushed cement (less than 10 micron) as filler in new cement production?

 

[jheidt2543]

I agree with Ron! We have nearly 100 years of material testing behind the concrete industry in the US. Why would you use an untested, waste material in a structural product just to use up the waste material? Even the use of fly ash in concrete has required considerable testing and is strictly controlled.

Before using anything out of the ordinary, I would check with both the Portland Cement Association (PCA) and the American Concrete Institute (ACI).

 

[Focht3]

Crushed cement, or crushed (recycled) concrete?



Please see FAQ731-376 by [blue]VPL[/blue] for tips on how to make the best use of Eng-Tips Fora.

 

[SirAl]

A good question that enticed me to research the web. I like the idea of recycling a spent product where appropriate.

From what I gather, foundry sand commonly contains 5% to 12% fines (by dry weight). This is too dirty for concrete applications. The gradation characteristics may, however, be suitable for a blend sand in an ACP applications. The literature that I came across indicates that this is an acceptable application with a caveat that a stripping test should be considered.

Try this link:

http://www.tfhrc.gov/hnr20/recycle/waste/fs1.htm

 

[jheidt2543]

When the State of Wisconsin reconstructed Interstate 90 up through the middle of the state about 10-12 years ago, they recycled the concrete paving. However, they used the crushed concrete for base course, they did not use it as aggregate for the new concrete.

Does anyone have information on using the crushed concrete as aggregate for new concrete?

 

[redlabel]

Crushed cement can be used as a base for new road construction but are there any uses for the ground cement (fine powder)?

 

[jheidt2543]

I think we should define terms AGAIN:

CEMENT is a fine powder ground from blast-furnace clinker (slag) of hydraulic calcium silicates.

CONCRETE is the product of an irreversable chemical reaction involving in correct proportions water, sand, aggregate and cement.

Cement is an ingrediant in concrete.

There is no such thing as a CEMENT contractor! They are concrete contractors, concrete construction etc. My material science prof. is rolling over in his grave people!

So, crushed CONCRETE can be used as an aggregate for base course. I'm not so sure if it can be used as an aggregate for concrete. CEMENT is already crushed by definition.

I feel better already! <G>

 

[redlabel]

sorry for the newbie questions... its concrete that we are looking at recycling in the manufacuring of new concrete.