This set of Basic Civil Engineering Questions and Answers for Experienced people focuses on “Types of Cement and Uses”.
1. What is the abbreviation of PPC?
a) Perfect Portland Cement
b) Portland Produced Cement
c) Portland Pozzolana Cement
d) Productive Portland Cement
Explanation: Pozzolana is a material containing silica. PPC is formed by intergrinding ordinary Portland cement, clinker, gypsum and pozzolanic material.
2. Which of the following is not an advantage of rapid hardening cement?
a) Faster construction
b) Short curing period
c) Light in weight
d) Higher final setting time
Explanation: The initial and final setting time of rapid hardening cement is the same as that of ordinary cement. It attains higher strength in less time. It develops the same strength of ordinary cement in four days rather than 28 days.
3. High alumina cement can be used for massive concrete work.
Explanation: High alumina cement is obtained by adding 55% bauxite and 35-45% lime. It hardens rapidly and it is costlier. It cannot be used for massive concrete work.
4. How many types of cement are there based on the ability to set in presence of water?
Explanation: The 2 types are hydraulic and non-hydraulic cement. Hydraulic cement sets and becomes adhesive due to reaction with water. Non-hydraulic cement does not set under-water or in wet conditions.
5. What property does air-entraining cement provide?
Explanation: Air-entraining agents are added to cement during manufacturing. These create voids and in turn increases workability when used in concrete.
6. Which of the following types of cement is used in marine structures?
a) Expanding cement
b) High alumina cement
c) Blast furnace slag cement
d) White cement
Explanation: Blast furnace slag cement is obtained by combining slag and cement clinkers. These have less heat of hydration and are not affected by sea water. Hence, can be used for marine structures.
7. Which pair of the compound and coloured cement mentioned below is wrong?
a) Iron oxide-yellow
c) Chromium oxide-green
d) Manganese dioxide-brown
Explanation: Cobalt imparts blue colour to cement. Iron oxide in different proportion imparts brown, red and yellow colour. Manganese dioxide produces brown and black coloured cement.
8. Low heat cement is ideal for use in the construction of dams.
Explanation: Heat of hydration is heat produced during chemical action between cement and water. In mass concreting works (dam) heat will be high and effect the stability of a structure. Hence, low heat cement is ideal for use.
9. Which of the following is not a pozzolanic material?
a) Fly ash
b) Silica fume
Explanation: Pozzolans are silicate based materials that form cementitious materials. Fly ash, silica fumes and slag are composed of oxide of silicon. Cinder is a coal residue.
10. Water proof cement is prepared by mixing ordinary cement with:
b) Water repellent chemicals
d) Metal stearates
Explanation: Resins are added in air entraining cement. Water repellent chemicals in hydrophobic cement. Sulpho-aminate is added in expanding cement. Metal stearates (Ca, Al, etc) are added in small percentage during grinding to get water proof cement.
Sanfoundry Global Education & Learning Series – Basic Civil Engineering.
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