Question

Which of the following cement is used in high temperature applications?
A.Expansive cement
B.High alumina cement
C.Portland blast cement
D.Portland pozzolan cement

Answer 1

Hint: High alumina cement form ceramic bonds at elevated temperature. Expansive cement is used for preventing water leakage and Portland cement is used widely on a daily basis for various purposes.

Complete step by step answer:
Cement is a light grey and fine powdered. It is a homogeneous mixture of silicates and aluminates of calcium. Ninety percent of cement is formed of aluminates and silicates. Raw material required to make cement is limestone, clay and gypsum. Limestone provides calcium hydroxide, clay contributes aluminium oxide and silica and gypsum contribute hydrated calcium sulphate. Gypsum is also used to slow down the process of setting of cement in order to increase hardness of cement.
When water is mixed to cement and the mixture is left it becomes very hard, this is known as the setting of cement. Portland cement is widely used cement all across the world. It is a mixture of mortar, concrete, stucco and grout. The fine powdered Portland cement is made from heating limestone and clay, with around three percent of gypsum. Its production contributes about 10 percent of present carbon dioxide emissions in the world today.
Five types of Portland cement are present namely: general Portland cement, Portland composite cement, Portland blast furnace cement, Portland pozzolanic cement and composite cement. In the given question, Portland blast furnace cement is the one which has a high contribution of blast furnace slag in it. Portland pozzolanic cement is the one which has about 55 percent contribution by pozzolanic particles.
High alumina cement is produced by fusing alumina (bauxite) and lime. This cement is resistant to chemical attacks and chemical corrosion and also hardens at a very high rate. High alumina cement is used for high temperature applications as alumina provides high tensile and mechanical strength to the cement even at high temperature. It acts as bonding material when added in refractory castables because it forms ceramic bonds at high temperature. Thus high alumina cements can be used even at high temperature. On the other hand, expansive cement is the one which is used to minimize cracking in concrete as it helps by preventing water leakage from the concrete. Expansive cement as they generate volume expansion and do not shrink and improve ordinary cement concrete.

Thus, the correct option is B.

Note:
Mortar is a mixture of cement, sand and water to give a proper consistency. Concrete is a mixture of cement, sand gravel and water. And when concrete is filled in beams of iron bars, it is known as RCC or reinforced concrete cement.