Question

Final setting time of cement should not be more than:
A. 1 hour
B. 2 hours
C. 5 hours
D. 10 hours

Answer 1

Hint:First, we need to understand the properties and composition of cement to derive its setting time. As we know that, a powdery substance formed by calcining of lime and clay. Then, it is mixed together with water to form mortar. Else it is mixed with sand, gravel and water to form concrete.

Complete step by step answer:

We all are aware that cement gets hardened when it comes in contact with the water. The hardening process of cement is called crystallization. The crystals formed in the reaction interlock with each other. Then, the recycled fly ash is mixed together with lime and water. Thus, it forms a compound known as cement which is known to be extremely strong and durable. This high-volume fly concrete ash can displace more than 25% of the cement. Also, it helps in reducing the amount of emissions for the formation of concrete mixture.
When cement is applied then initially, it takes more than 45 minutes as setting time of cement. This much time period is enough for transportation and placing of concrete on the floor before it starts to settle. After that the final setting time of the cement to settle should be less than 375 minutes. As 375 minutes is equal to 10.25 hours. Therefore, the final setting time of cement will take more than 10 hours.
Therefore, the option D is correct.

Note:
As we know that cement is used in construction of buildings, roads, bridges, and dams. The Portland cement comprises compounds like lime $CaO$ which is mixed with silica $Si{O_2}$ and alumina $A{l_2}{O_3}.$ Lime is obtained from a calcareous which is a raw material, and also has some other oxides which are derived from an argillaceous material.