Materials of Construction

GENERAL INFORMATION

Building Materials Laboratory is located on the ground floor of the Gazi University Engineering Faculty Laboratories Building. The laboratory has mezzanine work office and two warehouses: mezzanine: 5.4 x 10.8 + 9 x 4 = 92m2; working area: 9.3 x 16.4 = 152m2; two warehouses: 3.8 x 3.8 x 2 = 30 m2; total: 274 m2. In the laboratory, research projects and studies are carried out for undergraduate students. Most of the experiments for the mechanical, chemical and physical properties of materials are carried out in the laboratory. These include experimental work on building materials for both research and development. These studies generally include experiments on materials such as concrete, wood, cement and structural steel. The general view of the material laboratory is given below.

EXPERIMENTS IN THE LABORATORY

It is possible to collect the tests that can be done in the Building Materials Laboratory under three main headings: aggregate, cement and concrete tests. The experiments that are frequently performed under these main areas are given below in subheadings.

  1. Aggregate Tests
    1. Sieve Analysis experiments of aggregates
      1. Sieve Analysis experiments of Coarse Aggregate
      2. Sieve Analysis of Fine Aggregate
      3. Sieve Analysis of Raw Aggregate
    2. Unit Weight Tests of Aggregates
      1. Compact Unit Weight Test
      2. Loose Unit Weight Test
    3. Abrasion Test of Aggregate
      1. Los Angeles Experiment
    4. Determination of Impurity in Aggregates
      1. Clay-Soil Determination
      2. Organic Matter Determination
      3. Light Substance Determination
    5. Determination of Void Ratio in Aggregates
    6. Crush Test of Aggregate
  2. Cement Tests
    1. Determination of normal consistency in cement
    2. Determination of Set Start and End Times in Cement
    3. Determination of volume change in cement
    4. Determination of fineness in cement
    5. Determination of specific gravity in cement
    6. Strength tests on cement
      1. bending test
      2. pressure test
  3. Concrete Tests
    1. Thickness Tests of Fresh Concrete
      1. Slamp Experiment
      2. Compression factor Test
      3. Ve-Be Experiment
    2. Unit Weight Test of Fresh Concrete
    3. Strength Tests on Hardened Concrete
      1. bending test
      2. pressure test
      3. splitting experiment
    4. Non-Destructive Concrete Tests
      1. Schmidt hammer
      2. Ultrasound speed experiment

LABORATORY EQUIPMENT

Building Materials Laboratory has the following tools and equipment:

  1. Oven
  2. Curing Pool
  3. Sieve Set
  4. Weighing Instruments
  5. Blain Tool
  6. Los Angeles Tool
  7. Cone of collapse
  8. Compression Cone
  9. Vicat Tool
  10. Le Chatelier tool
  11. Concrete mixer
  12. 25 lt capacity mortar mixer
  13. 4 pieces of 5 lt, 15 lt and 20 lt mortar mixers
  14. Universal testing machine / schimadzu AG-X 100 Kn
  15. Cube, cylinder and prism moulds in different sizes
  16. 200-ton capacity pressure press
  17. Handheld crack measuring microscope
  18. Humidity cabinet with 120 lt capacity
  19. Freeze-Thaw tester
  20. Digital height meter
  21. Mortar shrinkage mould
  22. Pull-off tester
  23. Equipment used for the determination of physical and mechanical properties of cement and mineral additives
  24. Scales of different precision and size
  25. Necessary test setups for the determination of surface permeability and water absorption
  26. Gas permeability device
  27. Iron tensile tester
  28. 3 concrete mixing mixers in different volumes
  29. Concrete cutting device
  30. Concrete vibrator
  31. Three ovens of different sizes
  32. 4 restricted shrinkage moulds

Frequently used devices are listed below in detail.

It has 50x100x80cm dimensions with a front cover, has a heating capacity of up to 120 degrees and is used in undergraduate, project and graduate studies in order to dry the samples as follows:

 

  • Identity information about the sample and the project it belongs to are recorded on the test sheet.
  • Tare the container in which the sample is placed and recorded it on the test sheet.
  • Weigh the wet sample + container weight and record it on the test sheet.
  • It is placed in an oven at 105°C-110°C and dried for 24 hours or until the sample reaches a constant weight.
  • Dry sample + container weight is weighed and recorded on the test sheet.

Curing pool

It is temperature adjustable and thermostatic. It measures 50x50x185 cm. It is made of galvanized against mould formation. In particular, it is used in undergraduate, project and graduate studies to keep concrete samples in water at room temperature (24 degrees) for 2, 7, and 28 days, as follows:

  • Identity information about the sample and the project it belongs to are recorded on the test sheet and on the sample.
  • The plug of the curing pool is removed from the electrical outlet, the samples are placed in the curing pool, and the pool is plugged into the socket. While placing the sample in the curing pool, the electric plug of the pool is removed from the socket as a safety precaution against electric leakage.

Sieve set

The sieves have a diameter of 20 cm and a height of 8 cm. Sieve parts are brass, grid part is galvanized. It is used in undergraduate, project and graduate studies in order to separate the samples according to their sizes as follows:

  • The sieves are placed on top of each other as 4 inches, 3 ½ inches, 3 inches, 2 ½ inches, 2 inches, 1½ inches, 1 inch, 3/4 inches, 1/2 inches, 3/8 inches and collecting bowls.
  • The aggregate is placed on the top sieve, the sieve set is placed in the shaking machine. In the shaking machine, whose time and shaking intensity can be adjusted, the sieving process takes place by shaking for a certain period of time.
  • For coarse aggregate, the amounts passing through the sieve are weighed precisely.
  • During the sieving of the coarse aggregates, the aggregate collected in the collection container is defined as fine aggregate and sieved through the No:4, No:8, No:16, No:30, No:50, No:100 sieves placed in these aggregates, and the amounts remaining under the sieve. weighed precisely. It does not require any special clothing as a safety precaution.

Blain tool

Based on the principle of air permeability, serves to determine the fineness of the cement. The instrument consists of a perforated disc, sample cell, plunger, filter paper and manometer. The sample cell is made of corrosion-resistant hard metal, 1.27 cm in diameter and 5-6 cm in length. The perforated disc is 1cm in diameter and has 30-40 holes on it. The piston is such that it can easily enter the cell. The manometer consists of a U-shaped tube with a diameter of 0.9 cm and a length of 27.5 cm. There is a faucet 5 cm below the top of the pipe. It is a test instrument that is used to determine the fineness of cement based on the principle of air permeability and is generally used in undergraduate, project and graduate studies as follows:

  • A disc is placed at the bottom of the cell, and the filter paper is placed neatly on it.
  • The calibration sample is weighed on a balance sensitive to 0.1 gram and poured into the cell with a funnel.
  • By tapping the cell lightly on the table, the sheet is placed properly in the cell and is slowly compressed with the piston.
  • A new filter paper is placed on the top with the help of a plunger.
  • The piston head is carefully compressed until it touches the upper edge of the cell so that the sample does not rise above the filter paper, and the piston is pulled out slowly.
  • It is checked whether the liquid level in the manometer is at the bottom line of the U pipe.
  • After vaseline is applied outside the cell, it is placed on the manometer.
  • The mouth of the cell is closed with the thumb of the left hand in such a way that air cannot pass.
  • The air in the manometer is sucked by a rubber pump until the liquid level in the manometer tube reaches the top line.
  • By closing the tap, the liquid is kept at a certain level. The thumb of the left hand is withdrawn from the mouth of the cell.
  • As soon as the liquid level reaches the second line, the stopwatch is started.
  • When the liquid level reaches the third line, the stopwatch is stopped.
  • The flow time (t) is determined in seconds and the room temperature is recorded.
  • The average flow time (t) is found by measuring three separately prepared samples. It does not require special precautions and clothing to use.

 

Los Angeles Tool

The Los Angeles instrument consists of a sealed steel cylinder with an inner diameter of 71 cm and an inner length of 51 cm. It is made with an axle that does not pass through the cylinder, allowing rotation in the horizontal state. Inside the cylinder, there are 14 iron spheres with a diameter of 4.3 cm. It is used in undergraduate, project and graduate studies to determine the abrasion resistance of aggregates as follows:

  • Identity information about the sample and the project it belongs to are recorded on the test sheet.
  • It is checked that the inside of the Los Angeles tool is clean and that the iron balls are complete.
  • The amount of sample specified in the standard is put into the Los Angeles instrument and the lid is tightly closed.
  • The cycle counter is adjusted to 100 cycles and at the end of 100 cycles, the sample in the instrument is removed and sieved from the sieve specified in the standard. The ratio of the sample amount passing through the sieve to the total sample amount is determined as a percentage.
  • The same operations are repeated for 500 cycles and the ratio of the sample amount passing through the sieve to the total sample amount is determined as a percentage.

 Earplugs are used to protect the ears from loud noise as a safety precaution, as the Los Angeles tool makes excessive noise while operating.

 

 

 

Slump Cone

The slump cone test set consists of an inflexible cone with a lower diameter of 20 cm, an upper diameter of 10 cm and a height of 30 cm, and a 60 cm long metal iron rod. It is used as follows to determine the consistency of concrete (flowable, plastic, dry):

  • The inside of the mould is wiped with a wet cloth and the mould is placed on a flat, damp and water-proof surface.
  • It is held firmly until the mould is filled with concrete.
  • The concrete is placed in the mould in three layers, with each layer filling approximately one-third of the mould, that is, the vertical heights of the layers from the bottom of the mould should be 7.5 cm, 15 cm and 30 cm, respectively.
  • In order to ensure that the concrete is spread symmetrically in the mould, the concrete is poured by circling the bucket around the upper edge.
  • Each layer is skewered 25 times with a 60 cm long, 1.6 cm diameter, bullet-shaped skewer rod.
  • The strokes are evenly distributed in the cross-section of the mould and care is taken to hit the previous layer with a force that will penetrate 2.5 cm. The lowest layer is skewered along the entire depth.
  • After the top layer is skewered, the top of the mould is smoothed with a trowel and the concrete poured around the mould is cleaned on the ground.
  • Then, it is lifted vertically slowly and carefully by holding the mould handles.
  • The distance between the lower level of the stinging rod placed horizontally on the funnel placed next to the concrete pile and the average height of the upper face of the collapsed concrete is measured with a ruler to the nearest 0.5 cm. It does not require special precautions and clothing to use.

 

Compression Cone

It consists of two truncated cones and a cylinder. The upper truncated cone has an upper diameter of 25.4 cm, a lower diameter of 12.7 cm and a height of 27.9 cm. The lower cone has an upper diameter of 22.9 cm, a lower diameter of 12.7 cm and a height of 22.9 cm. The lower cylinder is 30.5cm high and 15.2cm in diameter. The cones are galvanized and are approximately 0.5cm thick. It is used as follows to determine the consistency of concrete (flowable, plastic, dry):

  • The inside of the mould is wiped with a wet cloth and the mould is placed on a flat, damp and water-proof surface.
  • Concrete is filled into a steel cylinder of definite volume and weight, equal to the volume of the upper cone of the compactor, by skewering with an iron rod. The concrete in the steel cylinder is then poured into the upper cone of the compactor.
  • Then, the lower cover of the upper cone is opened and the concrete inside the upper cone is filled into the lower cone.
  • The concrete filled into the lower cone is poured into the cylinder under the lower cone and the weight of the concrete in this cylinder is determined.
  • Concrete is filled without compression into a steel cylinder of definite volume and weight, equal to the volume of the upper cone of the compaction tool.
  • Then, the concrete in the steel cylinder is poured into the upper cone of the compactor, and the lower cover of the upper cone is opened, allowing the concrete in the upper cone to fill the lower cone.
  • The concrete filled into the lower cone is poured into the cylinder under the lower cone and the weight of the concrete in this cylinder is determined.
  • The compression coefficient is determined by proportioning the concrete weights in both cases. No special precautions or clothing are required to use the tool.

 

Vicat Tool

The Vicat tool consists of a steel mould and a needle into which the cement paste is placed. It is built on a table and is 30cm high. There is a cylindrical rod 1.5 cm in diameter, frictionless, with a Vicat needle (probe) attached to its tip, on the bent part of the table. It is used as follows in undergraduate, project and graduate studies to determine the set start and set expiry times of cement:

  • A weight of 27.5 g is placed on the top layer of the instrument and the needle is attached.
  • The gauge of the instrument is adjusted to point to zero when the needle touches the glass plate.
  • Cement paste prepared in normal consistency is placed inside the Vicat ring.
  • To determine the starting time of the cement paste, the Vicat probe is lowered until it touches the upper surface of the paste in the ring and the screw on the side is tightened.
  • The instrument is then released and the distance the probe sinks into the cement paste is measured. These processes are repeated several times and the measurements are renewed. The time from the preparation of the cement paste until the probe sinks 5-7 mm from the bottom of the cement paste is determined as the setting initiation time.
  • The same procedures are repeated to determine the setting expiration time with the Vicat needle. No special precautions or clothing are required to use the tool.

 

Le Chatelier Tool

The Le Chatelier instrument consists of a cylinder 3cm in diameter and 3cm high, with a slot in the middle, and two 15cm long 1.5cm thick rods attached to the middle of these slots. The instrument is used to determine the volume constancy in cement paste. It is made of brass and its cylindrical ring has a wall thickness of 0.5 mm, an inner diameter of 30 mm and a height of 30 mm. The cylindrical ring is slotted in the direction of its axis. Two 150 mm long rods are soldered to both sides of the slit and to the centre of the cylinder. It is generally used in undergraduate, project and graduate studies as follows:

  • Identity information about the sample and the project it belongs to are recorded on the test sheet.
  • The Le Chatelier tool is firmly attached to both sides of its rings to prevent its rods, which are soldered to the very centre of the cylinder, from opening.
  • The cement paste is placed in the tool, the rings are covered with glass from the top and bottom, and placed in the oven, kept at 105 degrees for 24 hours.
  • The opening between the bars of the ring is measured. This value should not be greater than the value specified in the standard.

 

 

Concrete mixer

In our laboratory, there are two concrete mixers with a capacity of 125 dm3 with horizontal and vertical axis. Concrete mixers, in experiments where the concrete mix is required; are used in undergraduate, project and graduate studies. Coarse aggregate, fine aggregate and water are placed in the concrete mixer at the specified weights and run for 3 minutes and the materials are mixed homogeneously. It does not require special precautions and clothing to use. However, since the concrete mixers are electric, the electrical plug must be removed from the socket while placing and discharging the sample.

LABORATORY SAFETY PRECAUTIONS

  1. General and special warning signs: “Caution High Voltage (Electrical Panel); Caution High Temperature (Oven); There are signs “No One Can Use It Other Than The Relevant Person”.
  2. Fire prevention. There is one fire extinguisher.
  3. Loud volume: There are two earphones.
  4. Collision, injury prevention: There are 8 helmets to prevent blows to the head.
  5. Splash prevention: There are 2 goggles in order to be protected from parts that may come into the eyes during operation.

 

The laboratory is open to undergraduate students within the scope of the building materials course. Students carry out their studies in groups and under the supervision of experts.

 

Laboratory manager:

Responsible Faculty Member: Prof.Dr. Abdussamet ARSLAN

Responsible Technical Personnel: Instructor Faruk Ogun and Hüseyin Kalkan

 

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