Date: Spring 2013
Is there a chemical that will quickly dissolve concrete? I need to remove a 70 cm square piece of concrete that is 25 cm thick. Due to the concrete's location I can not use tools such as grinders and jacks.
My son is a Civil Engineer and here is his reply:
Not that I know of. I know salt can deteriorate concrete, but not "dissolve" it quickly. Sulfuric acid is very detrimental to concrete, but it wouldn't work very quickly either. Any chemical that would dissolve concrete would be more corrosive than sulfuric acid, and would probably not be something you want to mess with outside of a lab.
I've heard of techniques where you drill pilot holes into the concrete and place an expanding grout in the holes. When the grout expands, it cracks the concrete, and you can remove the little pieces easier than the whole slab. See below.
The only thing that can "dissolve" this amount of concrete is large
amounts of a strong acid such as Hydrochloric Acid, but besides being
impractical it would be environmentally hostile.
Nothing that is safe for you to use.
Muriatic acid. You get it from a hardware store; it?s just concentrated hydrochloric acid. You will need a lot of it.
You could use pretty much any acid, but be aware that you will need a lot of it. And remember to wear the proper protective gear (rubber gloves, splash goggles). And if you wear cotton clothes, they will almost certainly develop holes after their next washing.
If there are any metal items next to or near the concrete sample, they will almost certainly corrode from the large amount of chloride you?re introducing to the system.
Richard E. Barrans Jr., Ph.D., M.Ed.
Department of Physics and Astronomy
University of Wyoming
Concentrated hydrochloric acid will work, but it is hazardous to handle and gives off toxic fumes. There are commercial products you can find on line if you search for "concrete remover" or "concrete dissolver" or some such title. I am not sure how effective they are, but in any case be very careful. Wear a full face protective eye shield, and appropriate gloves, apron etc.
My best recommendation is to have someone familiar with the process do it for you. It is just a nasty dangerous undertaking.
Thanks for the question. You may want to try soaking the concrete in muriatic acid (also known as hydrochloric acid) or phosphoric acid. It is going to take a substantial amount of time and acid to dissolve that much concrete. Be sure to follow all safety precautions as those acids are very corrosive to skin and eyes. Also, you will have to dispose of the waste slurry in an environmentally acceptable manner.
You may want to consider using a cold chisel and hammer. I have removed concrete using this method, but it does take a lot of time.
I hope this helps. Please let me know if you have more questions.
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