JNTU
JNTU B.Tech III CONCRETE TECHNOLOGY Previous Question Paper (November/December - 2018 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
List various types of mineral and chemical admixtures.
Answer
Mineral admixtures include fly ash, silica fume, ground granulated blast furnace slag (GGBS), and metakaolin. Chemical admixtures include plasticizers (water reducers), superplasticizers (high-range water reducers), accelerators, retarders, and air-entraining agents.
Define the characteristic mean strength and target mean strength.
Answer
Characteristic strength is the strength of concrete below which not more than 5% of the test results are expected to fall. Target mean strength is the average strength to be aimed at during mix design to ensure that the actual strength of the concrete produced meets the characteristic strength requirements, calculated as ft = fck + 1.65s, where s is the standard deviation.
Write the bulking of sand effects.
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List the sizes of sieves used in sieve analysis of fine and coarse aggregates
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Write effect of time on workability.
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What are various types of slumps and their significance?
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Explain the types of shrinkages in concrete.
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What is the significance of Gel-space ratio?
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Define the durability of the concrete.
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Explain the term 'effective water' in a mix.
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Part B
Explain the reactions of hydration of the main components in Portland cement.
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Explain the influence of compound composition of cement on the setting properties of cement.
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Discuss the structure of hydrated cement.
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Explain how the Bogue's compounds can be calculated.
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What are grading limits and why are they specified?
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Explain how alkali-aggregate reaction can be controlled.
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Explain the significance of Gap-graded aggregates.
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What is bulking of fine aggregate and how is it taken care of in the field?
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Explain the effect of time and temperature on the workability of concrete.
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Explain the purpose and procedure for penetration resistance test on concrete.
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What are the factors affecting the workability of the concrete?
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Discuss the effect of quality mixing water on the performance of concrete.
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Explain the maturity concept of concrete.
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How would you determine the dynamic modulus of elasticity?
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Explain any two non-destructive methods of testing concrete.
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Discuss in detail the relation between compressive and tensile strength of concrete.
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Explain the tests to determine the flow properties of Self-compacting concrete.
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What are the factors to be considered in the choice of concrete mix proportions?
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Explain the sampling and acceptance criteria for each concrete batch.
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Explain how ACI method is different from BIS method of mix design.
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