What are admixtures and why are they used?
Admixtures are materials that are added to the concrete to enhance certain characteristics that might be adversely affected by the addition of more cement or more water. Examples of some of these characteristics are set time, strength gain, slump, shrinkage resistance, and freeze/thaw resistance. There are liquid chemical admixtures such as water reducers, retarders, accelerators, air entrainers, and plasticizers. There are dry admixtures such as flyash and slag, which are by products of coal-fired power plants and steel production plants. There are fibers and colors used for shrinkage resistance and cosmetic enhancement.
