[amp_mcq option1=”Calcium oxide” option2=”Silica” option3=”Clay” option4=”Water” correct=”option1″]
The correct answer is: A. Calcium oxide.
Hydraulic lime is a type of lime that can set and harden under water. It is made by heating limestone to a high temperature, which removes the carbon dioxide and leaves behind calcium oxide. When calcium oxide is mixed with water, it reacts to form calcium hydroxide, which is a strong base. The calcium hydroxide then reacts with the silica and alumina in the limestone to form calcium silicate hydrates and calcium aluminate hydrates, which are the cementitious materials that give hydraulic lime its strength.
Silica and clay are both present in limestone, but they do not impart hydraulicity to the lime. Silica is a non-reactive material, and clay is a weak binder. Water is necessary for the hydration reaction to occur, but it is not the main constituent that imparts hydraulicity to the lime.
In conclusion, the main constituent which imparts hydraulicity to hydraulic lime is calcium oxide.