solve only when you are 100 Otherwise I will give negative r

solve only when you are 100%. Otherwise I will give negative rating.

1.50 What is the requirement of water (expressed as % of cement w/w) for the completion of chemical reactions in the process of hydration of OPC ? (a) 10 to 15% (b) 15 to 20% (c) 20 to 25% (d) 25 to 30%

Solution

Option C is correct.

It may be noted that C₃S requires 23% of water by weight of cement and C₂S requires 21%. It means that on an average 23% of water by weight of cement is required for chemical reaction with portland cement compounds. This 23% of water chemically combines with cement and therefore, it is called bound water. A certain quantity of water (about 15% by weight of cement) is imbedded within the gel pores. This water is known as gel-water. Therefore, a total 38% of water by weight of cement is required for the complete chemical reactions and to occupy the space within gel pores.