Since garage floors will be supporting heavy equipment such as cars and trucks, you need to make sure that the concrete mix you use will effectively provide the needed strength. To make your concrete mix, get some cement, sand, gravel, and water. The best combination would be 1 part cement, 2 parts sand (small aggregates), 3 parts gravel (large aggregate) and 1 part water. Mix all the dry materials first, and slowly add water as you go along. Mix all of these thoroughly together until the lumps disappear. Apply it evenly to your garage floor and let it dry thoroughly. This mixture is the best for garage floors because the large aggregate will greatly build an efficient foundation.