a Why do people add mineral admixtures in cement b why do pe

(a) Why do people add mineral admixtures in cement? (b) why do people add air entraining agents in cement?

Solution

People use admixtures primarily to reduce the cost of concrete construction; to modify the properties of hardened concrete; to ensure the quality of concrete during mixing, transporting, placing, and curing; and to overcome certain emergencies during concrete operations.

There are five distinct classes of chemical admixtures as per their function is concerned: air-entraining, water-reducing, retarding, accelerating, and plasticizers (superplasticizers). All other varieties of admixtures fall into the specialty category whose functions include corrosion inhibition, shrinkage reduction, alkali-silica reactivity reduction, workability enhancement, bonding, damp proofing, and coloring.