Testing of Material Properties

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CHAPTER I

• Testing of Material Properties

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1.1 Significance of testing materials

• The testing of materials may be performed with
  one of the three points below
• (1) to supply routine information on the quality
  of a product- commercial or control testing,
• (2) to develop new or better information on known
  materials or to develop new materials- materials
  research,
• (3) to obtain accurate measures of fundamental
  properties of materials- scientific measurement.

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Commercial testing

• Commercial testing is concerned with
• checking the acceptability of materials with
  respect to the specifications,
• control of production.
• Generally, the type of the test has been
  specified, standard procedures are used, and the
  object is to determine whether the properties of
  a material fall within the required limits.

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Materials research

• Materials research is done in order to
• obtain new understanding of known materials,
• discover the properties of new materials,
• develop meaningful standards of quality or test
  procedures.

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Scientific testing

• Scientific testing is the accumulation of orderly
  and reliable informations on the fundamental and
  useful properties of materials.

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What is the difference between experiments and
tests?

• Experimentation means that the outcome is
  uncertain, that new insights are to be gained.
• Testing is a more defined procedure, with the
  limits and results are clear.

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Materials testing may be carried out on

• 1. Full size structures, members, or parts,
• 2. Models of structures, members, or parts,
• 3. Specimens cut from finished parts,
• 4. Specimens of raw or processed materials,

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Destructive testing vs Non-destructive testing

• Destructive testing is carried out until the
  specimens failure. These tests are generally
  much easier to carry out, yield more information
  and are easier to interpret than non-destructive
  testing
• Non-destructive testing is the type of testing
  that does not destroy the test object. It is
  vital when the material in question is still in
  service.

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Field Tests vs Laboratory Tests

• Field tests usually lack the precision of similar
  tests conducted in the laboratory,
• However, some tests cannot be made in the
  laboratory and others cannot be made in the
  field.

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Precision Accuracy

• Precision repeatability of a measurement
• Accuracy its closeness to the true value
• Exp/ If an instrument consistently gives nearly
  identical but wrong readings- precise but
  inaccurate
• If readings vary considerably but do center about
  the true value- accurate but imprecise
• Test results should be both precise and accurate!

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1.2 Standard Specifications Standardizing
Agencies

• Specification A precise statement of a set of
  requirements, to be satisfied by a material,
  product, system or service. It is desirable that
  the requirements, together with their limits,
  should be expressed numerically in appropriate
  units.
• A standard specification for a material is the
  result of agreement between those concerned in a
  particular field and involves acceptance for use
  by participating agencies.

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Standardizing Agencies Relevant Standards

• Turkish Standards Institute (TSE)-Turkish
  Standards (TS) http//www.tse.org.tr/
• American Society for Testing and Materials
  (ASTM)- ASTM Specifications http//www.astm.org
• International Standards Organization (ISO)- ISO
  Standards http//www.iso.org
• European Commitee for Standardization (CEN)-
  European Norms (EN) http//www.cen.eu

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1.3 Properties of Engineering Materials

• Principal materials used in construction are
• metals,
• woods,
• portland cement concretes,
• bituminous mixtures,
• clay products,
• masonry materials,
• plastics.

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Engineering Materials

• The principal function of these materials is to
  develop
• Strength,
• Rigidity,
• Durability,
• adequate to the service for which they are
  intended.

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An important property- Strength

• The major work of the ordinary materials testing
  laboratory has to do with mechanical properties.
  mechanical testing
• A first requirement of any engineering material
  is adequate strength
• The term testing machine refers to a machine for
  applying loads.

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Properties of engineering materials-1
Class Property
General Density or specific gravity, Porosity Moisture content Macrostucture Microstructure
Chemical Oxide or compound composition Acidity or alkalinity Resistance to corrosion or weathering
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Properties of engineering materials-2
Class Property
Physico-chemical Water-absorptive or water-repellent action Shrinkage and swell due to moisture changes
Mechanical Strength Tension, compression, shear and flexure Stiffness Elasticity, plasticity Ductility, brittleness Hardness, wear resistance
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Properties of engineering materials-3
Class Property
Thermal Specific heat Expansion Conductivity
Electrical and magnetic Conductivity Magnetic permeability Galvanic action
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Properties of engineering materials-4
Class
Acoustical Sound transmission Sound reflection
Optical Color Light transmission Light reflection
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TASK

• Visit the Civil Engineering laboratory, notice
  where the general equipment is located.
• Learn the instruction of the operation of the
  compressive strength testing machine.

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References

• The Testing of Engineering Materials, H.E.
  Davis, G.E. Troxell and G.F.W. Hauck, McGraw-Hill
  Book Company, 1964.
• The Science and Technology of Civil Engineering
  Materials, J. F. Young S. Mindess R.J. Gray
  and A. Bentur, Prentice Hall, 1998.
• Civil Engineering Materials, S. Somayaji,
  Prentice Hall, NJ, 1995.
• Design and Control of Concrete Mixtures,
  Portland Cement Association, USA, 1979.
• www.wikipedia.org