MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
(Autonomous)
(ISO/IEC - 27001 - 2005 Certified)
Model Answer: Winter-2018
Subject: Concrete Technology Sub. Code: 22305
---------------------------------------------------------------------------------------------------------------
Important Instructions to examiners
1) The answers should be examined by key words and not as word-to-word as given in the model answer
scheme.
2) The model answer and the answer written by candidate may vary but the examiner may try to assess the
understanding level of the candidate.
3) The language errors such as grammatical, spelling errors should not be given more importance. (Not
applicable for subject English and Communication Skills.)
4) While assessing figures, examiner may give credit for principal components indicated in the figure. The
figures drawn by the candidate and those in the model answer may vary. The examiner may give credit
for any equivalent figure drawn.
5) Credits may be given step wise for numerical problems. In some cases, the assumed constant values may
vary and there may be some difference in the candidate’s answers and the model answer.
6) In case of some questions credit may be given by judgment on part of examiner of relevant answer based
on candidate’s understanding.
7) For programming language papers, credit may be given to any other program based on
equivalent concept.
---------------------------------------------------------------------------------------------------------------------------------
Que. Sub. Total
Model Answers Marks
No. Que. Marks
Q. 1 (A) Attempt any FIVE of the following : 10
a)
List four physical properties of OPC.
Ans. Physical properties of OPC:
i. Fineness
ii. Standard consistency or Normal consistency ½
iii. Initial and Final setting time each 2
iv. Soundness ( any
v. Compressive Strength four)
b) Define bulking of sand.
Ans. Bulking of sand is defined as increase in volume of given sand due to
surface moisture present on surface of particles. 2 2
c) State Duff Abraham’s water cement ratio law.
Ans. Duff Abraham’s Law: For workable concrete, the compressive
strength of concrete depends only on water-cement ratio. 2 2
d) Name four methods of concrete mix design.
Ans. i. Arbitrary proportion method
ii. Maximum density method
iii. Fineness modulus method
iv. ACI Committee 211 method ½
v. Road note no. 4 method (Grading Curve Method) each
vi. Indian road congress method (IRC - 44) ( any 2
four)
vii. High strength concrete mix design method
viii. Indian Standard method (IS 10262: 2009)
ix. Trial and error method
x. Surface area method
Page No.
, MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
(Autonomous)
(ISO/IEC - 27001 - 2005 Certified)
Model Answer: Winter-2018
Subject: Concrete Technology Sub. Code: 22305
---------------------------------------------------------------------------------------------------------------
Que. Sub. Total
Model Answers Marks
No. Que. Marks
Q. 1
xi. Mix design based on flexural strength
xii. 12.British DOE mix design method (Department of
Environment)
In sequence, write concreting operations.
e)
i. Batching of materials
Ans. ii. Mixing of materials 2 2
iii. Transportation of concrete
iv. Placing of concrete
v. Compaction of concrete
vi. Curing of concrete
vii. Finishing of concrete
f) State two purposes of using accelerating admixtures in the
concrete. 1
Ans. each 2
i. To accelerate the initial setting of concrete (any
ii. Permit early removal of formwork in cold climate. two)
iii. Reduce the required period of curing
iv. Speed of the work can be boosted by early removal of
formwork
g) State two uses of low heat cement.
1
Ans. i. It is used for mass concrete works such as dams. each 2
ii. It is used for cracks resistant structures. (any
iii. It is used for sulphate resistant structures. two)
iv. It used in concreting of nuclear power plant, sea walts, break
waters, etc.
Attempt any THREE of the following : 12
Q.2
Explain the method to determine initial and final setting time of
a) cement.
Ans. Procedure:
i. Take 400 gm. of cement sample and add 0.85 times water
required for its standard consistency to prepare homogenous
cement paste. Note down the time at which water is added to
cement as T1 min. 4 4
ii. Fill this cement paste in Vicat’s mould. Keep this mould under
Vicat’s apparatus with IST needle attached to it.
iii. Now allow the IST needle to penetrate in the paste by realize
pin observe the total penetration. If the penetration is not 33
Page No.
(Autonomous)
(ISO/IEC - 27001 - 2005 Certified)
Model Answer: Winter-2018
Subject: Concrete Technology Sub. Code: 22305
---------------------------------------------------------------------------------------------------------------
Important Instructions to examiners
1) The answers should be examined by key words and not as word-to-word as given in the model answer
scheme.
2) The model answer and the answer written by candidate may vary but the examiner may try to assess the
understanding level of the candidate.
3) The language errors such as grammatical, spelling errors should not be given more importance. (Not
applicable for subject English and Communication Skills.)
4) While assessing figures, examiner may give credit for principal components indicated in the figure. The
figures drawn by the candidate and those in the model answer may vary. The examiner may give credit
for any equivalent figure drawn.
5) Credits may be given step wise for numerical problems. In some cases, the assumed constant values may
vary and there may be some difference in the candidate’s answers and the model answer.
6) In case of some questions credit may be given by judgment on part of examiner of relevant answer based
on candidate’s understanding.
7) For programming language papers, credit may be given to any other program based on
equivalent concept.
---------------------------------------------------------------------------------------------------------------------------------
Que. Sub. Total
Model Answers Marks
No. Que. Marks
Q. 1 (A) Attempt any FIVE of the following : 10
a)
List four physical properties of OPC.
Ans. Physical properties of OPC:
i. Fineness
ii. Standard consistency or Normal consistency ½
iii. Initial and Final setting time each 2
iv. Soundness ( any
v. Compressive Strength four)
b) Define bulking of sand.
Ans. Bulking of sand is defined as increase in volume of given sand due to
surface moisture present on surface of particles. 2 2
c) State Duff Abraham’s water cement ratio law.
Ans. Duff Abraham’s Law: For workable concrete, the compressive
strength of concrete depends only on water-cement ratio. 2 2
d) Name four methods of concrete mix design.
Ans. i. Arbitrary proportion method
ii. Maximum density method
iii. Fineness modulus method
iv. ACI Committee 211 method ½
v. Road note no. 4 method (Grading Curve Method) each
vi. Indian road congress method (IRC - 44) ( any 2
four)
vii. High strength concrete mix design method
viii. Indian Standard method (IS 10262: 2009)
ix. Trial and error method
x. Surface area method
Page No.
, MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
(Autonomous)
(ISO/IEC - 27001 - 2005 Certified)
Model Answer: Winter-2018
Subject: Concrete Technology Sub. Code: 22305
---------------------------------------------------------------------------------------------------------------
Que. Sub. Total
Model Answers Marks
No. Que. Marks
Q. 1
xi. Mix design based on flexural strength
xii. 12.British DOE mix design method (Department of
Environment)
In sequence, write concreting operations.
e)
i. Batching of materials
Ans. ii. Mixing of materials 2 2
iii. Transportation of concrete
iv. Placing of concrete
v. Compaction of concrete
vi. Curing of concrete
vii. Finishing of concrete
f) State two purposes of using accelerating admixtures in the
concrete. 1
Ans. each 2
i. To accelerate the initial setting of concrete (any
ii. Permit early removal of formwork in cold climate. two)
iii. Reduce the required period of curing
iv. Speed of the work can be boosted by early removal of
formwork
g) State two uses of low heat cement.
1
Ans. i. It is used for mass concrete works such as dams. each 2
ii. It is used for cracks resistant structures. (any
iii. It is used for sulphate resistant structures. two)
iv. It used in concreting of nuclear power plant, sea walts, break
waters, etc.
Attempt any THREE of the following : 12
Q.2
Explain the method to determine initial and final setting time of
a) cement.
Ans. Procedure:
i. Take 400 gm. of cement sample and add 0.85 times water
required for its standard consistency to prepare homogenous
cement paste. Note down the time at which water is added to
cement as T1 min. 4 4
ii. Fill this cement paste in Vicat’s mould. Keep this mould under
Vicat’s apparatus with IST needle attached to it.
iii. Now allow the IST needle to penetrate in the paste by realize
pin observe the total penetration. If the penetration is not 33
Page No.
