Concrete Technology - May 2016

VTU Civil Engineering (Semester 4)

Total marks: --
Total time: -- INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary 1(a) Describe any five field tests that can be done on cement. 10 marks

1(b) Draw a flow chart for the manufacturing of cement by wet process. 10 marks

2(a) What do you understand by grading anslysis? Explain how it is done for fine aggregates. 10 marks

2(b) Mention the maximum impact value for wearing non-wearing surfaces and also explain how impact test is done for coarse aggregate. 10 marks

3(a) What is workability? Explain its importance in fresh concrete. 10 marks

3(b) List out any ten methods adopted for transportation of concrete. 10 marks

4(a) Explain the flocculation and de-flocculation of cement gains under the influence of superplasticizer, with the help of a diagram. 10 marks

4(b) Briefly explain the effect of fly ash on fresh and hardened concrete. 10 marks

5(a) Discuss any five factors affecting the strength of concrete. 10 marks

5(b) Discuss any five factors affecting the strength of results. 10 marks

6(a) List out any ten factors contributing to cracks in concrete. 10 marks

6(b) List out any five methods each for controlling sulphate attack and corrosion of steel due to chloride attack. 10 marks

7(a) Write short notes on the factors affecting the following :
a. Modulus of elasticity b. Shrinkage
c. Creep d. Workability 10 marks

8(a) With the help of the following design stipulations and test data for materials design a M20 grade concrete:
a. Design stipulations:
i) Characteristic compressive strength at 28 days= 20 N/mm²
ii) Maximum size of aggregate = 20 mm (angular)
iii) Degree of quality control = good
iv) Degree of quality control = good
v) Type of exposure = mild
b. Test data for materials:
i) Specific gravity of cement = 3.15;
ii) Specific gravity of coarse aggregate = 2.60;
iii) Specific gravity of fine aggregate = 2.60;
iv) Water absorption of coarse aggragate = 0.5%
v) Water absorption of fine aggregate = 1.0%
vi) Free moisture in coarse aggregate = Nil;
vii) Free moisture in fine aggregate = 2.0 %;
viii) Grading of fine aggregate = Zone III
Any missing data may be suitably assumed. 10 marks