Types of Admixtures
Concrete admixtures are used to improve the behavior of concrete under a variety of conditions and are of two main types: Chemical and Mineral.
Chemical admixtures reduce the cost of construction, modify properties of hardened concrete, ensure quality of concrete during mixing/transporting/placing/curing, and overcome certain emergencies during concrete operations.
Chemical admixtures are used to improve the quality of concrete during mixing, transporting, placement and curing. They fall into the following categories:
- air entrainers
-specialty admixtures: which include corrosion inhibitors, shrinkage control, alkali-silica reactivity inhibitors, and coloring.
Mineral admixtures affect the nature of the hardened concrete through hydraulic or pozzolanic activity. Pozzolans are cementitious materials and include natural pozzolans (such as the volcanic ash used in Roman concrete), fly ash and silica fume.They can be used with Portland cement, or blended cement either individually or in combinations.