SPPU Civil Engineering (Semester 4)
Concrete Technology
May 2015
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


Answer any one question from Q1 and Q2
1 (a) What are the minor compounds in Portland cement? What is their role.
6 M
1 (b) Explain the physical properties of aggregates affecting workability of concrete.
6 M

2 (a) What are the functions of types of admixtures?
6 M
2 (b) Define creep of the concrete. What are the factors affecting creep of concrete.
6 M

Answer any one question from Q3 and Q4
3 (a) State the various types of non-destructive tests carried on hardened concrete. Explain 'Impact echo test' for determination of concrete properties.
6 M
3 (b) Describe the types of vibrators used for compaction of concrete.
6 M

Write short notes on:
4 (a) (i) Cellular light weight concrete.
3 M
4 (a) (ii) Self-compacting concrete.
3 M
4 (b) Define Ferro cement. Explain the basic concepts in forming ferro-cement composites used in the construction industry.
6 M

Answer any one question from Q5 and Q6
5 Using Indian Standard recommended guidelines, design a concrete mix for a reinforced concrete structure to be subjected to the mild exposure conditions for the following requirements:
A) Stipulations for proportioning:- a) Grade designation: M30, b) Standard deviation, s=5, c) Type of cement: OPC 43 grade conforming to IS8112, d) Workability: 75 mm (slump), e) Degree of supervision: Good, f) Type of aggregate: Angular coarse aggregate, g) Maximum cement content: 450 kg/m3.
B) Test data for Materials:
a) Specific gravity of cement: 3.15, b) Specific gravity of:
i) Coarse aggregate-2.74
ii) Fine aggregate-2.74
c) Water absorption:-
i) Coarse aggregates - 0.5%
ii) Fine aggregates - 1.00%.
d) Free surface moisture:
i) Coarse aggregates - Nil (absorbed moisture also nil)
ii) Fine aggregates ?Nil
e) Sieve analysis:
i) Coarse aggregate:
IS Sieve Sizes (mm) Analysis of Coarse Aggregate Fraction Percentage of different Fraction Remarks
  I II I (60%)  II (40%) Combined (100%)

Confirming

of Table 2

of IS 383

20

10

4.75

2.36

100

0

 

 

100

71.2

9.40

0

60

 0 

 

 

40

28.5

3.7

 

100

28.5

3.7

 

ii) Fine aggregate: Conforming to grading zone I

C) Design considerations:

Table 1: From IS 10262; Maximum water content per cubic meter of concrete:

Sr. No. Nominal Maximum Size of Aggregate Maximum Water Content (kg)

(i)

(ii)

(iii)

10

20

40

208

186

165

Table 2: From IS 10262; Volume of Coarse Aggregate per Unit Volume of Total Aggregate:

Sr. No.
(1)
Nominal Maximum Size of Aggregate (mm)
(2)
Volume of Coarse Aggregate per Unit Volume of Total Aggregate for Different Zones of Fine Aggregate
    Zone IV Zone III Zone II Zone I

(i)

(ii)

(iii)

10

20

40

0.50

0.66

0.75

0.48

0.64

0.73

0.46

0.62

0.71

0.44

0.60

0.69

Table 3: From IS 456; Different exposure conditions for reinforced concrete:

Sr. No. Exposure Minimum cement content (kg/cubic m) Maximum free water cement radio Minimum grade of concrete

(i)

(ii)

(iii)

(iv)

(v)

Mild

Moderate

Severe

Very Severe

Extreme

300

300

320

340

360

0.55

0.50

0.45

0.45

0.40

M20

M25

M30

M35

M40

13 M

6 (a) Write major factors affecting mix design. Explain water cement ratio.
4 M
6 (b) Write a short note on statistical quality control of concrete.
4 M
6 (c) Explain DOE method of mix design in brief.
5 M

Answer any one question from Q7 and Q8
7 (a) State and explain factors affecting permeability of concrete. What measures should be taken to reduce permeability of concrete?
8 M
7 (b) Explain in detail corrosion monitoring techniques of reinforcement and its preventive measures.
5 M

Write short notes on:
8 (a) (i) Sulphate attack on concrete.
4 M
8 (a) (ii) Carbonation of concrete and its determination.
4 M
8 (b) What are the symptoms of distress of concrete?
5 M



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