Overmixing concrete reduces the quality of the concrete, grinds the aggregate into smaller pieces, raises the temperature of the mix, reduces the slump, reduces air entrainment, and reduces the strength of the concrete. Overmixing also causes unnecessary wear on the transit mixer's drum and blades. Concrete that is overmixed requires more water to achieve a proper consistency and increases the amount of time it takes to harden. As long as you don't exceed the recommended dose of admixtures, concrete can be overmixed. Excessive roller traffic can also overwork the concrete, causing it to appear dull and gray instead of white or light brown. If this happens, stop mixing for a few days until the color returns to normal. Concrete that is overmixed may look clean when first poured but will soon become dry and dusty inside your garage, basement, or other area where it cannot be exposed to sunlight. The only cure for overmixed concrete is to remove it and start over with fresh ingredients. There are several ways to do this including grinding up old concrete to use as aggregate for new batches or simply adding more water if the mixture appears too dry. If you overmix concrete, you need to add more water so that the mixture reaches its desired consistency. This is called "slumping" the concrete. When slumping concrete, it is important not to add too much water, otherwise, the cement will not set properly.