This is a common problem that we see quite often. People always tell us that their basement floors are dusty, even though they sweep them all the time. There is actually an industry term for this: concrete dusting, the floor is dusting. The top layer of concrete is soft, and you can often scrape it with your fingernail.
There are three main causes of concrete dusting:
The first is called Bleeding. Concrete has water in it. When concrete is poured on the floor, the water rises. This is called bleeding the concrete. You are supposed to wait until the concrete is done "bleeding". Once the water has completely risen, you can then start working it with your trowels. If you do it too soon, you are likely to cause dusting.
If it is a warm humid day, the concrete is cold, and cold water is used for mixing. This causes condensation. This condensation is water and this can cause that top bit of the floor to be soft and cause dusting. In reverse, if you pour it on a cold day and the concrete is cold, there is also going to be condensation from the air.
The third thing that can cause dusting is improper ventilation and you are using gas or propane from machines; the machines let chemicals into the air which interact with the chemicals in the concrete which can cause softening of the concrete which causes dusting. So, you need to have the right ventilation in order to get the chemicals in the air away from the concrete.
These are the three main areas that can be worked on when pouring concrete in order to prevent dusting.
If you have a floor that is dusting, you can stop it even if it is used for a day or thirty years. We use a special hardening formula on the concrete that will harden the concrete and stop the dusting.
If you have any questions or basement waterproofing, contact A1 Foundation Crack Repair.