Concrete Technology MCQ Paper – 6 Welcome to your concretetechnologymcqpaper-6 1. The most useless aggregate is one whose surface texture is Smooth Granular Glassy Honey combed and porous None 2. To obtain a very high strength concrete, use very fine grained Granite Magnetite Barite Volcanic scoria None 3. Pick up the correct statement from the following: Calcium chloride acts as a retarder Gypsum (calcium sulphate) acts as an accelerator Gypsum (calcium sulphate) acts as a retarder Calcium chloride acts as an accelerator Both (c) and (d) None 4. Joints in concrete structures, are provided To reduce the tensile stresses likely to be developed due to evaporation of water To minimise the change in the dimensions of the slab To minimise the necessary cracking All the above None 5. If the effective working time is 7 hours and per batch time of concrete is 3 minutes, the output of a concrete mixer of 150 litre capacity, is 15, 900 litres 16, 900 litres 17, 900 litres 18, 900 litres None 6. The condition not applicable to water cement ratio law, is Internal moisture conditions on hydration continue till complete strength is gained Concrete specimens may be tested at any temperature Concrete specimens need be of same age Concrete specimens need be of same size None 7. High temperature Increases the strength of concrete Decreases the strength of concrete Has no effect on the strength of concrete None of these None 8. The factor which affects workability, is Water content and its temperature Shape and size of the aggregates Grading and surface textures of the aggregates Air entraining agents All the above None 9. Slump test of concrete is a measure of its Consistency Compressive strength Tensile strength Impact value None 10. Saw dust can be rendered chemically inert by boiling it in water containing Ferrous sulphate Potassium chloride Ammonia Nitric acid None 11. Pick up the incorrect statement from the following: In properly graded aggregates, bulk density is more In single size aggregates, bulk density is least In single size aggregates, bulk density is maximum None of these None 12. According to Water-Cement Ratio Law, the strength of workable plastic concrete Depends upon the amount of water used in the mix Does not depend upon the quality of cement mixed with aggregates Does not depend upon the quantity of cement mixed with aggregates All the above None 13. If the engineer-in-charge approves, the 10 cm cubes may be used for the work test of concrete provided maximum nominal size of aggregate, does not exceed 10 cm 15 cm 20 cm 25 cm None 14. The diameter of the Vicat plunger is 10 mm and its length varies from 20 mm to 30 mm 30 mm to 40 mm 40 mm to 50 mm 50 mm to 60 mm None 15. The shrinkage of concrete is proportional to water content is the mix<br>is proportional to cement concrete is proportional to cement concrete Increases with age of concrete All the above None 16. The ratio of various ingredients (cement, sand, aggregates) in concrete of grade M 20, is 1 : 2 : 4 1 : 3 : 6 1 : 1.5 : 3 1 : 1 : 2 None 17. Separation of water or water sand cement from a freshly concrete, is known Bleeding Creeping Segregation Flooding None of these None 18. Permissible compressive strength of M 150 concrete grade is 100 kg/cm2 150 kg/cm2 200 kg/cm2 250 kg/cm2 None 19. Pozzolana cement is used with confidence for construction of Dams Massive foundations Abutments All the above None 20. Efflorescence in cement is caused due to an excess of Alumina Iron oxide Silica Alkalis None Time’s up
