OK here is a weird question. What do they use acid for in the concrete making process? I was curious because at work I am rebuilding a CAT 980 wheel loaders hydraulic system because it supposedly had acid put in the hyd tank causing rust and all the chrome to be removed. what kind of acid is it

 

there need not be any acid mixed to make concrete (hence the term, "just add water"), but often times people will do acid staining or acid etching in concrete to give it a different color or texture. some of the contractors around here may be able to better answer it. i believe this is done once the concrete is mixed and poured, not while it is still being mixed.

 

its acid stain or etching

 

i was wondering what acid is used at the concrete plant in either the making process or the cleaning of equipment.

the acid stain or etching pic is very cool though

 

ConcreteGuy could probably help ya

 

The acid in concrete is the natural alkili that are in the ingredients
that make up portland cement and the chemical process in making it.

So the type of acid is a alkili.

Hope that helps.

Sled...

 

sorry sleddogg, but what you wrote is an oxymoron. an alkali, by definition is a base, not an acid. it is impossible for the acid type to be "alkali" because that would mean it is a base. also, alkali is a general term, not a specific type of base.

http://dictionary.reference.com/search?q=alkali

it is worth noting however that strong bases can do just as much damage as strong acids. Drano, for example, is a very strong base (KOH and/or NaOH). i'm pretty sure they use an acid and not a base in making cement mixes, but perhaps in some techniques they use a base instead, I have no idea.

 

I dont know my bases from a hole in the ground. Just got that info from Chemistry of portland cement site off google search.

There was absolutely no mention of acid, other than the alkili bases mentioned and the effects it has on oxidizing metal which comes in contact with cement.

Sorry bout the mix up. Better just stick to brain surgery I guess.

Sled...

 

They use acid to remove dried concrete from metal surfaces. A mixer may get cement on its wheels, the will use Muriatic acid (a diluted form of Hydrocloric acid) to remove it.

 

Ok I see you got it right for the most part...Muriatic acid which is used in a diluted form of Hydrocloric acid can clean stuff of concrete...It can be used to help the bond between old concrete and a new pour...BUT...It is not mixed in the making of concrete...

You can find cement, gravel, water, superplazers, water reducers, fly ash, added chemicals to speed the set or retare it, etc , added to the concrete mix depending on what/where your using the concrete and what time of year your using it...Some concretes will rot copper pipes and other metals and they need be protected to see this does not happen...Concrete is also very hard on your skin or eyes and YOU need protect yourself when pouring it and finishing it...

So you know that Concrete is a mix of materials that gives of heat as it sets..causing a chemical reaction...going from a soft to hard state...

Hell its a product that was used thousands of years ago ...my memory and spelling is not so good ,sorry,...but I have all the books and tapes here and even samples of the ad mix materials used ...I shows them at my workshops...

So I hope Something I said helped you here...Thanks for asking...

 

My driveway is a steep slope.... How could a person utilize muriatic to 'clean' the driveway prior to resealing? I mean, if I just pour it on and go to work, I'm obviously going to have run off. Plus, is this a chemical that could be LEGALLY discharged to my storm sewer? Also, is it going to etch/clean all the way around the culvasac to the storm drain? (it's three or four houses down the road).

 

RP,

so you're finally breaking out the big guns to get those bicycle tire marks off, huh? i would suggest, having seen a pic of your driveway, that you us a bucket and a stiff brush. dip the brush in the acid solution and then scrub the trie marks. you could also mop it on. DON'T just pour it on the driveway and let it run. the package will also have some suggestions I'm sure.

When you're done cleaning you should hose down the driveway well. All the run off will go to the storm drain and that's fine. It will be diluted so it won't do anything as it runs down the street. Just make sure to keep the water going for 5 or 10 minutes as you hose down the driveway.

Then you get to break out the sealant and seal the driveway once it dries! Have fun!

 

After the sealer, use a final coat of NXT and have it shine like that KR.

Sled...

 

Come on RP, you should know this...

Hydroflouric acid is used to clean the dried concrete off of cement trucks and equipment. Do not try this at home!!!!!!!!! HFl is a strong acid that is absorbed by the skin and goes to the bone, where it basically reacts to turn bone into powder.
HFl is used because it is a strong acid that quickly reacts with the calcium carbonate (also known as lime or limestone) in the dried concrete.
Muriatic acid is another name for hydrochloric acid, regardless of the concentration. HCl is often sold in pool stores as muriatic acid. You can use HCl to clean concrete; however, if it isn't diluted, it will etch and scar the concrete (always add acid to water, NOT water to acid - it a hypothermic reaction that gives off a lot of heat and can turn water to steam and splash acid).

RP, if you want to clean your concrete you can use powdered dishwasher soap and a stiff bristled broom. You can always use bleach (again if it isn't diluted it can casue pitting and scarring); however, you would still have to contain the runoff from getting into the storm sewer. Which you could do by 'borrowing' some socks from the office, or some inlet protection covers from a local construction site. If you decide to go the acid or bleach route and not 'borrow' anyhting, don't forget the old adage "the solution to polution is dilution"

Isn't your driveway less than a year old? Why does it need resealing already?

 

I work within the concrete manufacturing industry and most ready mix producers are moving away from using acid to clean their equipment because of the damage it causes. However what they use to clean theirs trucks etc wont work on your driveway.

go to home depot or lowes and buy muratic acid, a stiff brush attached to a broom handle, a 5 gal bucket, and some heavy duty rubber gloves.

the acid bottles have dilution directions for cleaning concrete which is the main reason they sell it. (I use it to lower the PH in my pool) It is nasty stuff and the vapor can kill you and etch metal! So make sure it is not a humid day (Less vapor) wear eye protection and long sleeves. now add the proper amout of acid to the proper amount of water (as noted above ONLY add acid TO water never the reverse) now scub to your hearts content and make sure you don't miss any spots because they will show. now rinse the heck out of everything with tons-o-water and don't worry about the runoff it will cause no harm at those levels.

good luck and have fun!!