# Question about asbestos in concrete



## chandler48 (Jun 5, 2017)

Asbestos is only really dangerous if it is friable, or in dust form. I am not a concrete pro, but would not think adding asbestos to any concrete product would have been to any advantage. The main use for asbestos was heat/cold retention, and to fireproof things. Concrete doesn't burn to readily so adding it would not be beneficial.


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## joed (Mar 13, 2005)

A simple google search of 'asbestos in concrete' shows that asbestos was indeed used in some concrete as a fiber to prevent cracking.


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## Sch84 (Jun 22, 2017)

Correct asbestos was used in concrete products and is still used in some concrete products around the world. In fact there are lists that show what those products are. However nothing on the web says anything about it being used in concete porches or concrete steps. It wasn't used in all concrete applications. For example there are numerous sites that show you where to look for asbestos in your home. None of them say anything about concrete porches or steps. I know it was used is in mortar a lot. There's also varying information about its use in cinder blocks. At least I think my foundation is made with cinder blocks. They look like them. I'm basically asking if anyone has ever encountered asbestos in concrete porches or stairs or cinder block foundations. Anyone who's done abatement, demolition or construction.


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## mark sr (Jun 13, 2017)

I had never heard of asbestos in concrete [but then I'm a painter] Generally if you keep it wet while removing, asbestos dust won't become airborne reducing the odds of any danger to the workers. Could your white powder be efflorescence?


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## concretemasonry (Oct 10, 2006)

I think mark has a very good point. People see something they do not understand, so they cry wolf.

The use of asbestos in concrete products is very, very rare. I have been in concrete plants in 45 countries during my 50 years as an engineer and have it used only once for a unique process and product. - Plain and simple, it is more costly, does no good and generally would be detriment for common products. There are several types of rock that contain very small amounts and those types are not used as aggregates.

Fibers have been used for some types of concrete, but they add to the cost. The common fibers are fiberglass, steel and possibly polyester, but they are costly and add significantly to the required equipment and complexity.

Dick


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## Bud9051 (Nov 11, 2015)

Thanks Dick,
Even if it has a small amount of asbestos the remediation would basically be the same as the repair because no one would suggest removing everything. As stated keep it wet, don't grind it and create a lot of dust and then regardless you will sleep better.

Bud


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## concretemasonry (Oct 10, 2006)

The asbestos in the rock is already encapsulated in rock. Breaking down the large aggregate into smaller fractions (still gravel or coarse aggregate) does not release a significant amount of asbestos. The rock processing plant I worked at was governed by the bureau of Mines and OSHA and the employees did not have to wear any respirators unless the were working in the 90' deep pit posing a crusher. - Masks were provided for the optional use by the employees.

The rock that is used to make cement (limestone or dolomite) is a sedimentary rock and does not contain asbestos. You may see some fibers in concrete products from the glass fibers or poly fibers that are frequently used to increase the tensile/shear properties. The white powder seen on concrete in service is efflorescence is essentially Calcium Carbonate or Magnesium Carbonate the is the deposit from dissolved compounds that migrate to the surface and are left after air drying.

There is a big difference between dust and respirable asbestos.

Dick


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