28 + Interview Questions in Repair Technology For Concrete Structures in Concrete Technology Page 1 InterviewSolution

1.	Is it possible to have 0% crack in our building?(a) Yes(b) No(c) May be(d) Can’t be determinedThe question was posed to me during an online exam.Origin of the question is Cracking of Concrete, Evaluation of Cracks topic in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» RIGHT choice is (B) No For explanation I would SAY: It is not possible to have 0 % cracks in any building after construction. We can PREVENT it but we can’t stop it.

Discussion

2.	Powder epoxy is fusion bonded to bar at about _________0C temperature.(a) 100(b) 250(c) 300(d) 350I had been asked this question in homework.My enquiry is from Symptoms and Diagnosis of Distress topic in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct choice is (b) 250 To explain I would say: Fusion BONDED epoxy coating PROCESS has good results in protecting reinforcement bars from CORROSION. Powder epoxy is fusion bonded to bar at about 2500C TEMPERATURE.

Discussion

3.	The rate of creep rapidly ___________ with time.(a) Increase(b) Decrease(c) Doesn’t affect(d) Depends on the temperatureI have been asked this question by my school principal while I was bunking the class.Question is taken from Defects Occurring During Construction in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» CORRECT CHOICE is (b) Decrease For explanation: The RATE of creep rapidly decreases with time. The time taken by a concrete STRUCTURE to attained creep is 5 years.

Discussion

4.	Evaluation of cracks ________ be determined before cracking.(a) Can(b) Can’t(c) Sometimes(d) Depends on the structureThis question was posed to me in exam.This interesting question is from Cracking of Concrete, Evaluation of Cracks topic in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» CORRECT OPTION is (a) Can The best I can explain: Evaluation of cracks can be determined before cracking i.e., DUE to plastic and CONSTRUCTIONAL MOVEMENTS.

Discussion

5.	What is the maximum w/c ratio?(a) .2(b) .3(c) .4(d) .5I have been asked this question in a job interview.Asked question is from Cracking of Concrete, Evaluation of Cracks in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» Right ANSWER is (d) .5 To explain: Water cement RATIO should not exceed .5 in CONCRETING because it will reduces the workability of the concrete.

Discussion

6.	Symptoms for acid attack?(a) It will show disintegration of the concrete evidenced by loss of the cement paste(b) It will show concrete surfaces that are very rough in areas where the paste is leached(c) Affected concrete does not exhibit telltale features too distinctly(d) Expansion does not occur without reaction productsThe question was asked in a national level competition.This is a very interesting question from Symptoms and Diagnosis of Distress topic in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct OPTION is (a) It will SHOW DISINTEGRATION of the CONCRETE evidenced by loss of the cement paste The explanation: ACID attack will show disintegration of the concrete evidenced by loss of the cement paste.

Discussion

7.	Creep is ____ to the strength of concrete.(a) Equal(b) Similar(c) Directly proportional(d) Inversely proportionalThis question was addressed to me by my school teacher while I was bunking the class.Enquiry is from Symptoms and Diagnosis of Distress in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct OPTION is (d) INVERSELY PROPORTIONAL To explain: Creep INCREASES with increase in water/cement ratio. In other words, it can also be said that creep is inversely proportional to the strength of CONCRETE.

Discussion

8.	Which can be the possible option for cracking in the building?(a) Due to light load(b) Low w/c ratio(c) Temperature difference(d) Gain of waterI have been asked this question by my college professor while I was bunking the class.This is a very interesting question from Cracking of Concrete, Evaluation of Cracks topic in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct answer is (c) Temperature difference Easiest EXPLANATION: Concrete expands and SHRINKS when the temperature CHANGES which directly LEADS to cracking in the building.

Discussion

9.	How can we prevent cracks in concrete structures?(a) Due to heavy load(b) Low w/c ratio(c) Settlement of structure(d) High water cement ratioThis question was addressed to me during a job interview.My question is taken from Cracking of Concrete, Evaluation of Cracks topic in division Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct choice is (B) Low w/c ratio Best EXPLANATION: Low w/c ratio will DIRECTLY affect the quality of concrete. A lower water cement ratio LEADS to high strength in concrete therefore lesser CRACKS.

Discussion

10.	What is the moisture content in slurry for wet process?(a) 35-50%(b) 12%(c) 40-45%(d) 100%This question was posed to me at a job interview.Origin of the question is Defects Occurring During Construction in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» The CORRECT OPTION is (a) 35-50% Best explanation: The MOISTURE CONTENT in SLURRY for wet process is 35-50%. 12% is the moisture content for dry process.

Discussion

11.	A ratio of core height-to-diameter of __________ gives a standard cylinder test.(a) 1(b) 2(c) 3(d) 4I had been asked this question by my college professor while I was bunking the class.I'm obligated to ask this question of Destructive Testing topic in section Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct CHOICE is (b) 2 To EXPLAIN: A ratio of core height-to-diameter of 2 gives a standard cylinder TEST. The ratio of core height to diameter and the location where the core is taken affect the strength.

Discussion

12.	The use of crushed aggregates may results in 10 to 20% higher compressive strength.(a) True(b) FalseThis question was posed to me by my college professor while I was bunking the class.Enquiry is from Defects Occurring During Construction topic in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» Right answer is (a) True For explanation I would say: The use of crushed AGGREGATES may results in 10 to 20% higher compressive strength DUE to development of stronger aggregate-mortar BOND.

Discussion

13.	Which of the following compound is used for fine polishing?(a) Aluminum oxide(b) Nitric oxide(c) Silicon carbide(d) Iron oxideThe question was asked in an online quiz.Enquiry is from Destructive Testing topic in division Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct ANSWER is (a) Aluminum OXIDE Explanation: Powder form of aluminum oxide is USED for fine polishing process. It is surface TREATMENT process.

Discussion

14.	What should be the minimum water cement ratio?(a) .45(b) .5(c) .45I have been asked this question in an interview.The origin of the question is Symptoms and Diagnosis of Distress topic in division Repair Technology for Concrete Structures of Concrete Technology
Answer» The CORRECT option is (C) <.45> Explanation: CONCRETE should be workable with MINIMUM water cement ratio (< 0.45). It should be well compacted by vibrator.

Discussion

15.	Reduction in the volume due to shrinkage causes __________(a) Low volume(b) Volumetric strain(c) Volumetric stress(d) W/c ratioThis question was posed to me in class test.My doubt stems from Defects Occurring During Construction in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct option is (b) VOLUMETRIC strain Easiest explanation: Reduction in the VOLUME DUE to SHRINKAGE causes volumetric strain in FRESHLY hardened concrete.

Discussion

16.	The rate of creep generally ____________ with the ____________ of the size of aggregates.(a) Increase, increase(b) Decrease, decease(c) Increase, decrease(d) 2.5, 12mmThe question was posed to me in my homework.My doubt is from Defects Occurring During Construction topic in section Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct OPTION is (c) Increase, decrease Easy explanation: The rate of creep generally DECREASES with the increase of the size of AGGREGATES. TIME rate of deformation of a material subject to stress at a constant temperature. It is the slope of the creep vs. time DIAGRAM obtained in a creep test.

Discussion

17.	It is about __________ times the tensile stress determined by the splitting test.(a) Equal(b) .5(c) 1.5(d) 2This question was posed to me in a national level competition.My enquiry is from Destructive Testing in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct option is (c) 1.5 The best I can explain: The theoretical maximum tensile stress at the bottom face at FAILURE is calculated. This is termed the MODULUS of rupture. It is about 1.5 times the tensile stress DETERMINED by the splitting TEST.

Discussion

18.	Evaluation of cracks _________ be determined after cracking.(a) Can(b) Can’t(c) Sometimes(d) Depends on the structureThis question was posed to me in exam.My query is from Destructive Testing topic in division Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct answer is (a) Can To ELABORATE: Evaluation of cracks can be determined after cracking i.e., due to structural, THERMAL, CHEMICAL, physical activities.

Discussion

19.	Symptoms for aggressive ACR reaction?(a) It will show disintegration of the concrete evidenced by loss of the cement paste(b) It will show concrete surfaces that are very rough in areas where the paste is leached(c) Affected concrete does not exhibit telltale features too distinctly(d) Expansion does not occur without reaction productsI had been asked this question in examination.This interesting question is from Symptoms and Diagnosis of Distress topic in section Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct OPTION is (c) Affected concrete does not exhibit telltale features too distinctly Easy EXPLANATION: ACR affected concrete does not exhibit telltale features too distinctly. AAR results in deleterious expansive cracking of concrete occurring at the LATER AGES after construction.

Discussion

20.	Dry intervals in surface wetting leads to ____________(a) Cracking(b) Fogging(c) High strength(d) Good workabilityI had been asked this question during a job interview.Question is from Defects Occurring During Construction in division Repair Technology for Concrete Structures of Concrete Technology
Answer»

Discussion

21.	At the construction stage, binding wires ____________(a) Should touch the formwork(b) Should not touch the formwork(c) To be turned outside(d) To be turned whole structureI had been asked this question during an interview.I'd like to ask this question from Symptoms and Diagnosis of Distress in section Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct OPTION is (b) Should not TOUCH the formwork The explanation: Binding wires to be TURNED INSIDE (should not touch formwork). G.I. wires to be used in AGGRESSIVE environment.

Discussion

22.	Symptoms for aggressive ASR?(a) It will show disintegration of the concrete evidenced by loss of the cement paste(b) It will show concrete surfaces that are very rough in areas where the paste is leached(c) Affected concrete does not exhibit telltale features too distinctly(d) Expansion does not occur without reaction productsThis question was posed to me during an online exam.Enquiry is from Symptoms and Diagnosis of Distress in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct CHOICE is (d) Expansion does not occur WITHOUT REACTION PRODUCTS Explanation: Harmful ASR expansion does not occur without reaction products. But reaction products can occur without harmful ASR expansion.

Discussion

23.	In Concrete core test the strength is ________ at the top and _________ at the bottom.(a) Lowest, lowest(b) Lowest, highest(c) Highest, lowest(d) Highest, highestI had been asked this question in examination.This interesting question is from Destructive Testing topic in portion Repair Technology for Concrete Structures of Concrete Technology
Answer» Right choice is (b) LOWEST, highest Easiest EXPLANATION: The strength is lowest at the top surface and increases with depth through the ELEMENT.

Discussion

24.	Compressive strength of hardened concrete is done by _________(a) Cube test(b) Tensile splitting test(c) Concrete core test(d) Flexure testI have been asked this question in exam.I need to ask this question from Destructive Testing in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct OPTION is (a) CUBE test The explanation: Compressive strength of hardened concrete is done by cube test. For cube test two TYPES of specimens EITHER cubes of 15cm X 15cm X 15cm or 10cm X 10cm x 10cm depending upon the size of aggregate are used.

Discussion

25.	Which one can’t be the reason for the shrinkage of concrete?(a) W/c ratio(b) Temperature(c) Cement content(d) FormworkI got this question by my school teacher while I was bunking the class.My question comes from Cracking of Concrete, Evaluation of Cracks in section Repair Technology for Concrete Structures of Concrete Technology
Answer» Right choice is (d) Formwork Explanation: Formwork can never cause SHRINKAGE in CONCRETE EVEN it HELPS to reduce the shrinkage in concrete.

Discussion

26.	Plastic shrinkage cracking occurs in ________ hours after placing.(a) .5(b) 24(c) 10(d) 5The question was asked in semester exam.I'd like to ask this question from Cracking of Concrete, Evaluation of Cracks topic in section Repair Technology for Concrete Structures of Concrete Technology
Answer» Correct answer is (d) 5 Easy explanation: PLASTIC SHRINKAGE concrete occurs within 1 hours and 8 hours after PLACING, when subjected to a very rapid loss of MOISTURE.

Discussion

27.	Cement not more than ________ months old should be used.(a) 1(b) 1.5(c) 2(d) 3I had been asked this question in an interview for job.I need to ask this question from Symptoms and Diagnosis of Distress topic in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct answer is (d) 3 To explain: CEMENT not more than 3 months OLD should be used. Proper cement to be used to prevent sulphate and chloride attack.

Discussion

28.	Symptoms for aggressive water attack?(a) It will show disintegration of the concrete evidenced by loss of the cement paste(b) It will show concrete surfaces that are very rough in areas where the paste is leached(c) Affected concrete does not exhibit telltale features too distinctly(d) Expansion does not occur without reaction productsThe question was asked by my school principal while I was bunking the class.This intriguing question comes from Symptoms and Diagnosis of Distress topic in chapter Repair Technology for Concrete Structures of Concrete Technology
Answer» The correct CHOICE is (B) It will show concrete surfaces that are very ROUGH in areas where the PASTE is leached To elaborate: It will show concrete surfaces that are very rough in areas where the paste is leached.

Discussion

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Is it possible to have 0% crack in our building?(a) Yes(b) No(c) May be(d) Can’t be determinedThe question was posed to me during an online exam.Origin of the question is Cracking of Concrete, Evaluation of Cracks topic in portion Repair Technology for Concrete Structures of Concrete Technology

Powder epoxy is fusion bonded to bar at about _________0C temperature.(a) 100(b) 250(c) 300(d) 350I had been asked this question in homework.My enquiry is from Symptoms and Diagnosis of Distress topic in portion Repair Technology for Concrete Structures of Concrete Technology

What is the maximum w/c ratio?(a) .2(b) .3(c) .4(d) .5I have been asked this question in a job interview.Asked question is from Cracking of Concrete, Evaluation of Cracks in chapter Repair Technology for Concrete Structures of Concrete Technology

What is the moisture content in slurry for wet process?(a) 35-50%(b) 12%(c) 40-45%(d) 100%This question was posed to me at a job interview.Origin of the question is Defects Occurring During Construction in portion Repair Technology for Concrete Structures of Concrete Technology

Which of the following compound is used for fine polishing?(a) Aluminum oxide(b) Nitric oxide(c) Silicon carbide(d) Iron oxideThe question was asked in an online quiz.Enquiry is from Destructive Testing topic in division Repair Technology for Concrete Structures of Concrete Technology

What should be the minimum water cement ratio?(a) .45(b) .5(c) .45I have been asked this question in an interview.The origin of the question is Symptoms and Diagnosis of Distress topic in division Repair Technology for Concrete Structures of Concrete Technology

It is about __________ times the tensile stress determined by the splitting test.(a) Equal(b) .5(c) 1.5(d) 2This question was posed to me in a national level competition.My enquiry is from Destructive Testing in portion Repair Technology for Concrete Structures of Concrete Technology

Evaluation of cracks _________ be determined after cracking.(a) Can(b) Can’t(c) Sometimes(d) Depends on the structureThis question was posed to me in exam.My query is from Destructive Testing topic in division Repair Technology for Concrete Structures of Concrete Technology

Dry intervals in surface wetting leads to ____________(a) Cracking(b) Fogging(c) High strength(d) Good workabilityI had been asked this question during a job interview.Question is from Defects Occurring During Construction in division Repair Technology for Concrete Structures of Concrete Technology

Plastic shrinkage cracking occurs in ________ hours after placing.(a) .5(b) 24(c) 10(d) 5The question was asked in semester exam.I'd like to ask this question from Cracking of Concrete, Evaluation of Cracks topic in section Repair Technology for Concrete Structures of Concrete Technology

Cement not more than ________ months old should be used.(a) 1(b) 1.5(c) 2(d) 3I had been asked this question in an interview for job.I need to ask this question from Symptoms and Diagnosis of Distress topic in chapter Repair Technology for Concrete Structures of Concrete Technology