Can You Use Cement That Has Hardened In The Bag?

Ryan Womeldorf
by Ryan Womeldorf
Cement that hardens in the bag can feel like a death blow to any project. However, that doesn’t necessarily mean that the entire bag of cement is useless. Follow along as we explore how you can determine whether or not cement will still be useful once it’s hardened and what you can do about it.

Cement can serve a lot of different purposes and come in a number of forms. One of the most commonly used forms of concrete is a cement mix that comes in large sacks or bags and can be implemented by pouring the mixture in with water and applying it to the desired area.

What happens if the concrete gets wet in the bag and hardens? The good news is that, depending on how much of the bag has hardened, you can still use the cement for a variety of purposes. It is important to know how much has hardened before potentially using it.

Why Did the Cement Mix Harden?

When the cement mix inside of the bag starts to harden, either on the outer layer or throughout, the most likely cause is that it has been exposed to moisture of some sort. Not only that, but there is most likely a perforation or tear in the bag that allowed access for the moisture.

It is important to store cement mix in a dry, secure place. Otherwise, you could wind up with a bag of cement mix that has hardened before you ever get to use it. And that is just wasted time and money in the long run.

How Can You Use Cement That Has Hardened?

The good news is that even if the bag of concrete is rock hard after being exposed to moisture, you can still use it. It should crush and break apart relatively easily using a hammer. While you won’t be able to make the same use of the first bag, you can mix it into a mixture containing three bags of fresh concrete and use it for household repairs.

Keep in mind that when this happens, you will want to keep those aggregate pieces of concrete towards the bottom of your pour. This will allow for a more even distribution and will keep any nasty lumps from forming in your new mixture.

Can Hard Cement Be Softened?

With new concrete, something that has been left to dry or cure for under 48 hours, you can generally soften the concrete. But anything that has been drying for more than a couple of days typically can’t be softened for easy removal.

When trying to remove hard cement, it will need to be broken up. The purpose of softening concrete is to help ensure that it can be removed in a fast, effective manner without doing any damage to machinery or surfaces.

Does Vinegar Dissolve Concrete?

While vinegar does not dissolve the concrete itself, it can actually work to degrade the cement that works to bind the entirety of the concrete together. Since vinegar is a weak, dilute acid, it will only result in very minor surface damage to concrete.

Additionally, vinegar can work to take the shine off of some polished surfaces, leaving it looking dull and less-than-new.

What Dissolves Concrete?

When a masonry job has been finished, it is not uncommon to have leftover concrete that can’t be used in future projects. This facilitates the need to dissolve and break down that dried concrete so that it can be properly disposed of.

Generally speaking, trisodium phosphate and phosphoric acid are used to break down that leftover concrete, but there are times where it doesn’t really work. When that happens, you can resort to muriatic acid, which is an industrial-strength hydrochloric acid. Just make sure that you wash away any other aids on the concrete and put on all of your protective safety gear before using it.

How to Dissolve Concrete

After a job is done, there is a chance that you may have some concrete left over that cannot be used in future projects. When this is the case, you can dissolve the remaining concrete so that it can be properly disposed of.

The first thing you need to do in order to dissolve concrete is to put your safety gear on. Even weaker acids can have a very negative impact on your eyes and skin, so protect them at all costs from potential exposure to those acids.

Open up a box of baking soda and have a hose nearby to neutralize any potential acid spills. Make sure that you also spread out some kind of tarp over any areas that you don’t want to get acid on and if you are cleaning the concrete inside, open up the windows to give you the proper ventilation.

Start by using a trisodium phosphate or a phosphoric acid first. Even though these are weaker acids, they may just do the job. Spread them over the concrete using a mixture with water (whatever the manufacturer recommends). If it works, you can then scrape the area that has the acid spread over it with a putty knife.

Should you need something tougher, you can go with a muriatic acid or a hydrochloric acid depending on the toughness of the concrete. Just make sure to continue using proper protection and ventilation and you should be able to successfully dissolve the concrete.

Can a Bad Concrete Job Be Fixed?

Sometimes concrete can be improperly installed and either won’t sit right or won’t look right. In most cases, when aa concrete job is poorly installed, there is no saving it. When that is the case, the cement slab will need to be removed entirely and a new one poured in its wake.

It is also safe to assume that if you notice visible finishing that was done poorly, there are problems beneath the surface. Starting over is the best course of action even though it may be a huge pain in the butt to do.

What is the Lifespan of Concrete?

Generally speaking, concrete can last anywhere from 30 to 100 years for larger projects like homes and buildings. This all depends on the style of construction used and the method with which the concrete was installed.

Most of the time, a concrete shell of a home or building can even be reused whenever other materials like wood start to suffer and deteriorate. Over time, weather conditions can denigrate the condition of the concrete, shortening its lifespan.

What Causes Cement to Crumple?

Even though concrete seems like a permanent and stable material, it actually remains porous and has the ability to retain water. When there is water that gets trapped inside of the concrete and then freezes, it will actually push the cement binder apart from the inside.

When this expansion occurs – and the contraction that comes when that water melts again – it can cause the cement to start to crumble. This will ultimately degrade the quality of the concrete and require that it be replaced in due time.

How Do You Make Concrete Stronger?

Concrete is generally rated on a system that designates its strength when it has been mixed and cured for a month’s time. To make the concrete stronger, you can add less sand or more cement; the closer you can get your ratio to one-to-one, the stronger the rating of the concrete should be when it finally cures.

The stronger the concrete, the longer it should be able to hold up.

Related Guides

Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

More by Ryan Womeldorf