Writing Task 1

The diagrams illustrate producing process of cement and the role of cement in making concrete.

Overall, cement is produced by mixing , heating and grinding mixture of clay and limestone. Thus, cement is used as one of the ingredients in making concrete in special mixer.

First of all, limestone and clay have to be crashed and mixed. Then, mixture rotates in special cylinder-shaped barrel by affecting of heat which provided by heater in the end of the cylinder. Finally, powder falls into grinder before packing in bags.

In terms of making concrete there are ingredients including cement. However, the main ingredient is gravel which contains a half of the whole mixture. The fourth of all ingredients comes into sand , whereas there is only 10 percent of water needed for producing concrete. Although cement is important , it provides only 15 percent of materials for the concrete mixer, where concrete remains in liquid condition.