The concrete bags are solid which you can use for storing the leftover. The preparation is easy and needs to keep stirring after addition of water until it gets the creamy feel.
A simple, cheap trowel is completely fine to finish the job. Drying does not take too long. Around 3-4 hours is enough to see the hardening concrete overnight.
Bags are available in;
Build Retaining Walls with Concrete Bags
Read here about how ready mix concrete is processed
Build the retaining walls to hold back soil and other types of dirt. You will notice retaining walls built around stairways or on the freeway where there are hills. You can create retaining walls in gardens or yards to create different levels or around the base of a home to prevent the ground beneath the foundation from eroding and sliding away.
There are block retaining walls, stone retaining walls and poured concrete retaining walls but these can be quite complicated and expensive. A simple cost-effective way to make a retaining wall is to stack 60-lb. concrete bags. Over time the bags will degrade and you will have an elegant and permanent retaining wall.
The concept is that you don’t open the packaging. If you lay the bags, it will wet everything down completely with a hose, saturating all of the bags. Once the concrete sets up, you can either wait for the paper to biodegrade, peel it off, or burn it off.
Prior to wetting the concrete, you can effortlessly drive rebar into the bags as reinforcement. You can also use the technique to build sunken fire pits. If you want to use “bricks” that are smaller in size than your standard concrete bags, you can put in some extra work and re-bag the concrete in smaller lunch bags.
Concrete bags and Its Forethought
The plastic bags tear easily and are sometimes leaking even in the store. And the bags are intentionally designed with tiny pinhole perforations – be careful not to store these bags on damp ground or you might get some hardened blobs inside.
In conclusion, concrete bags should be used within a few months of purchase, but if kept dry and airtight, It can be successfully used many concrete mixes that are older than that.