Building Materials, Third Edition

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3. With the same w/c ratio, the lower the maximum size of aggregate the strength of
   concrete
   (a) increases (b) decreases
   (c) remains same (d) can’t say


4. When the cement content and workability are kept constant, the greater proportion of fine
   aggregate will be required if
   (a) maximum size of aggregate is more
   (b) maximum size of aggregate is small
   (c) all in aggregate is used
   (d) rounded coarse aggregate is used


5. Pick out the incorrect statement.
   (a) To check segregation the sp. gr. of fine aggregate should not be more than that of
   coarse aggregate
   (b) When concrete is to be placed under water more fine aggregate is used to provide
   cohesiveness
   (c) For high workability fine aggregate required will be more
   (d) With small maximum size of coarse aggregate a small proportion of fine aggregate
   will be required


6. Following data is available in a mix design
   Coarse aggregate
   Batch weight 1350 kg/m^3
   Water absorption 2%
   Fine aggregate
   Batch weight 500 kg/m^3
   Water absorption 0.5%
   The inference made from the above data is/are:
   
   
   1. The quantity of coarse aggregate should be decreased by 27 kg.
   
   
   2. The quantity of fine aggregate should be increased by 2.5 kg.
   
   
   3. The quantity of mixing water per m^3 should be increased by 29.5 kg.
      Of the above, the correct answer is
      (a) 1, 2 and 3 (b) 1 and 2 (c) 2 and 3 (d) 1 and 3
   
   
   
   


7. The cement content in a mix design is 378 kg/m^3 , water content 170 kg, sand is 30% of
   total aggregate, entrapped air is 1%, sp. gr of cement, coarse aggregate and fine aggregate
   are respectively 3.15, 2.70 and 2.60. The fine aggregate will be approximately
   (a) 510 kg (b) 550 kg (c) 600 kg (d) 450 kg

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1. (b) 2. (b) 3. (a) 4. (b) 5. (d) 6. (d) 7. (b)