10 Tips for Fast Setting Concrete
Fast-setting concrete is incredibly easy to work with. It is important to know some tips and tricks to help make working with it easier, especially if you are new to it. With that in mind, we asked our Fastener Expert, Bob, to tell us some tips we should think about when working with fast setting pre-mixed concrete. Below are his top tips for working with concrete.
Never worked with fast-setting concrete before? No Problem! Read this post as well: How to Mix Fast Setting Concrete
1. Bags of Pre-Mixed Concrete Can Be Bad When You Buy Them
To use Fast-Setting Concrete, all you must do is add water to the pre-mix. This sounds simple, but often when being delivered to the store, the mix is exposed to the elements. If caught in the rain or humidity long enough, the concrete mix will absorb some of the moisture and begin hardening.
When you first buy and open a bag, you’ll want to check for any large chunks of hardened concrete. Not only will you not be able to use this bit, but it will also change how much space the concrete can cover. If there are any large chunks, bring it back to the store it was bought from and get it changed out for a new bag.
2. Fast-Setting Concrete Sets Quickly
This one may seem self-explanatory, but often someone will begin mixing the concrete prematurely resulting in the concrete beginning to harden prior to placing it where it needs to go. A better method is to make sure all materials are present and any spreading or moving tools are also present and ready before mixing the concrete.
3. Before Mixing the Concrete
Ok, so the tools are out, you have your location set up and now you need to mix the concrete right? Wrong. First add the concrete pre-mix into your bucket. Then take the mixing tool, whether it be a concrete spreader or a concrete mixing auger, and mix the dry pre-mix.
This practice helps prevent large clumps from being an issue later. Before adding anything to the pre-mix ensure that it is mostly loose, and any chunks are broken down. Try to make the pre-mix as fine as possible before use.
4. Don’t Use Hot Water
When mixing fast-acting concrete with water, use cold water. Hot water will make the mix harden significantly more quickly.
When adding the water to the concrete pre-mix, take a tool and scoop out the middle creating a hole. Pour the water into the hole. This will help during the mixing process as some of the water is now closer to the pre-mix at the bottom of the bucket.
5. Start Slow and Add Water a Bit at a Time
To get the concrete mix to a good consistency, add the cold water a little at a time. Doing so prevents the pre-mix from getting too thin or “soupy”. Ultimately, this type of concrete should be a thicker sludge consistency (chunky and thick) when done properly.
Don’t panic if too much water is added during the mixing and it becomes too thin. Just add more concrete to the mix and keep mixing until there are no dry spots left inside the container. This is when a battery-drill and concrete mixing bit come in handy.
6. Make It More Wet If You Are Less Experienced
Fast-setting concrete sets very quickly, as the name suggest. If you are inexperienced with working with concrete, add a little extra water to the mix. This will increase the amount of time it takes the concrete to set. *Note: When adding extra water, you still do not want to compromise the sludge-like consistency. Just add a little bit more than normal.
7. If Mixing A Lot, Start Off With Too Much Water
If the project is going to require a large amount of concrete, add some of the pre-mix then add in too much water. This may sound contradictory, but it makes the mixing process easier than trying to get the water mixed down to the bottom of a 50 lb. bag of pre-mx. Imagine if it was with 10 bags. Mixing would be incredibly difficult.
8. If the Mix Begins to Set Throw It Out
Using fast-setting concrete requires the project to be fast from start to finish. If the mix begins to harden and set in the bucket before the job is complete, throw it out.
Even if only a very small amount is needed to complete the project, mix fresh concrete to finish the job. Unfortunately, adding more material this way will cause a cold joint (see tip 9 for more details).
9. Adding Wet Concrete Mix to Set Concrete Forms a Cold Joint
Due to the way concrete dries, when you add more concrete to the old set material, it will not properly connect to the old concrete. This can cause cracks prematurely in the material. The location where fresh mix is added to set concrete is referred to as a cold joint. If possible, avoid these and get the entire job done at once. This will significantly increase the lifespan of the concrete.
10. Bag Your Bag of Pre-Mix for Next Time
As we went over earlier, Concrete Pre-Mix is a very dry substance. If left in a humid environment, it will absorb the moisture out of the air and begin hardening. To prevent this, after you’ve opened a bag of concrete, roll up the bag as much as possible and tuck it into a plastic garbage bag.
Attempt to get as much of the air out of the garbage bag as possible before tightly tying it shut. This will greatly increase the shelf-life of the mix.
Extra Tips:
We know we said 10 tips, but we just couldn’t finish this post without mentioning the posts below.
Extra Tip 1: Wear A Mask, Long-Sleeves and Gloves
Concrete pre-mix is incredibly dry. When pouring it into the bucket you are going to use, the powder will fly all over the place coating whatever is nearby. To best protect yourself from the material, use a mask (rated for the material) to prevent breathing it in.
Also wear long sleeves and gloves while working with the material. Concrete has lime in it. If skin is exposed to the pre-mix, especially often, it will harm and damage the skin.
SHOP SAFETY GEAR
Cleaning Out the Bucket
Many people do not think about what happens to the concrete after you finish a project. It is common to find inexperienced users have washed it out in their sink or bathtub. DO NOT DO THIS. Washing out concrete into the plumbing of a house can cause expensive damages. Often the concrete will stick in the catch or to a pipe and begin accumulating other debris blocking up the pipes or septic system. The best solution is to wash out the bucket outside with a hose. It will leave a residue in the grass (or a chunk of concrete depending on how much you’ll be washing out. While that is not ideal it is better than damaging your house’s internal plumbing.
Now that you’ve learned all the tips and poured your concrete, you’re going to need fasteners to attach something to it. Check them out here: Masonry Anchors and Concrete Screws
