CE1355 Concrete Technology B.E Question Bank : kings.ac.in
Name of the College : Kings College of Engineering
University : Anna University Chennai
Department : Civil Engineering
Subject Code/Name : CE 1355 Concrete Technology
Year : III
Semester : VI
Degree : B.E
Website : kings.ac.in
Document Type : Question Bank
Download :https://www.pdfquestion.in/uploads/ki…TECHNOLOGY.pdf
Kings Concrete Technology Question Paper
Unit – I
Part-A :
1. What is the common classification of aggregates? :
The most common classification of aggregates on the basis of bulk specific gravity is
** lightweight,
** normal-weight, and
** heavyweight aggregates.
Related : Kings College of Engineering CE1356 Railway Engineering B.E Question Bank : www.pdfquestion.in/1548.html
2. What is Lightweight aggregates? :
lightweight concrete contains aggregate that is natural or synthetic which weighs less than 1100 kg/m3. The lightweight is due to the cellular or high internal porous microstructure, which gives this type of aggregate a low bulk specific gravity. The most important aspect of lightweight aggregate is the porosity. They have high absorption values, which requires a modified approach to concrete proportioning.
3. Define Heavyweight aggregates.
Heavyweight concrete contains aggregates that are natural or synthetic which typically weigh more than 2,080 kg/m3 and can range up to 4,485 kg/m3. Heavy weight aggregate is most commonly used for radiation shielding, counterweights and other applications where a high mass-to-volume ratio is desired.
4. Define Aggregate.
Aggregates are defined as inert, granular, and inorganic materials that normally consist of stone or stone-like solids. Aggregates can be used alone (in road bases and various types of fill) or can be used with cementing materials (such as Portland cement or asphalt cement) to form composite materials or concrete.
5. Mention the Classification of aggregate In accordance with size.
Coarse aggregate : Aggregates predominately retained on the No. 4 (4.75 mm) sieve. For mass concrete, the maximum size can be as large as 150 mm. Fine aggregate (sand): Aggregates passing No.4 (4.75 mm) sieve and predominately retained on the No. 200 (75 µm) sieve.
6. Mention the Classification of aggregate In accordance with source.
Natural aggregates : This kind of aggregate is taken from natural deposits without changing their nature during the process of production such as crushing and grinding. Some examples in this category are sand, crushed limestone, and gravel. Manufactured (synthetic) aggregates: This is a kind of man-made materials produced as a main product or an industrial by-product. Some examples are blast furnace slag, lightweight aggregate (e.g. expanded perlite), and heavy weight aggregates (e.g. iron ore or crushed steel).
7. What are the properties of Aggregate? :
Moisture conditions : The moisture condition of aggregates refers to the presence of water in the pores and on the surface of aggregates. Density and specific gravity
Density (D) : weight per unit volume (excluding the pores inside a single aggregate)
SolidVweightD= Bulk density : the volume includes the pores inside a single aggregate.
7. Give the Grading of aggregates :
Grading – size distribution
The particle size distribution of aggregates is called grading. The grading determine the paste requirement for a workable concrete since the amount of void requires needs to be filled by the same amount of cement paste in a concrete mixture.
8. Define Fineness modulus of aggregate.
To characterize the overall coarseness or fineness of an aggregate, a concept of fineness modulus is developed. To calculate the fineness modulus, the sum of the cumulative percentages retained on a definitely specified set of sieves needs to be determined, and the result is then divided by 100. The sieves specified for the determination of fineness modulus are No. 100, No. 50, No. 30, No. 16, No. 8, No. 4, 3/8″, 3/4″, 1.5″, 3″, and 6″.
9. Define Fineness modulus for blending of aggregates :
Blending of aggregates is undertaken for a variety of purposes, for instance, to remedy deficiencies in grading. The fineness modulus of blended aggregates can be calculated if the values for the component aggregates are known.
10. What are the Physical Quality requirements Of aggregates :
These requirements can be divided into five distinct groups as follows :
** Absorption;
** Abrasion resistance;
** Soundness;
** Restrictions on deleterious constituents; and
** Special requirements.
11. What are the Various test which are to be done on aggregates ? :
Various test which are done on aggregates are listed below
** Sieve Analysis
** Water Absorption
** Aggregate Impact Value
** Aggregate Abrasion Value
** Aggregate Crushing Value
12. What is the chemical composition of cement? :
Chemical composition of cement is lime, silica, alumina, calcium sulphate Iron oxide Magnesium oxide Sulphur trioxide Alkali oxides.
13 List various types of cement.
** Ordinary Portland cement
** High alumina cement
** Portland Pozzolana cement
** Quick setting cement
14. What is grade of cement? List any three grades of cement with their strengths.
Grade of cement represents the specific 28 days compressive strength. The following three grades are given along with their compressive strengths
33 Grade OPC –33 MPa
43 Grade OPC – 43 MPa
53 Grade OPC – 53 MPa
15. Give step by step method of manufacture of cement by wet process.
** Limestone is first crushed
** Mixed with clay or shale and ground
** The ground material is corrected and mixed with water
** Corrected slurry is sprayed on to the upper end of a rotary kiln
** Slurry looses moisture and forms as flakes
** Clinker forms
** Clinker is cooled and gypsum is formed
16. What is meant by proportioning of concrete? :
Proportoining concrete is use of certain quantity of cement, sand and coarse aggregate and specific water cement ratio.
17. Can sea water be used for making concrete? Explain.
In general any potable water is suitable for concreting. To be specific pH of water should be between 6&8. Sea water contains sodium chloride whose pH does not fall in the above limit.
18. What is meant by curing of concrete? :
In order to prevent the loss of water from the surface due to evaporation or otherwise it has to be retained for which certain measures are taken which is called curing.
UNIT – II
Part-A :
1. Mention the Properties of concrete at Early Ages .
Workability
Slump Loss
Segregation/Bleeding
Plastic Shrinkage
Time of Set
Temperature
2. What are the Causes of bleeding and segregation?
Improper slump
Excessive amount of coarse aggregate
Lack of fines
Inappropriate placing and compacting
3. What are the Methods for Control of Bleeding?
Reduction of water
Introduction of fines and air
Proper Compaction (too much compaction
Causes bleeding)
3. Define Workability
Effort required manipulating a concrete mixture with a minimum of segregation.
It is not a fundamental property of concrete consistency (slump) –> how easy to flow cohesiveness –> tendency to bleed andsegregate.
4. Is Concrete Really Elastic?
In a word, yes. But the elasticity is a way to characterize the mechanical response of the material body for applied stresses that stay within the linear regime. Very large stresses, which are high enough to fracture the material, cause non-linear deformations.
These values vary greatly depending on the overall makeup of the concrete mixture. Many of the non-fracture-related mechanical properties of concrete are characterized by the elastic moduli.