Concrete test
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TEST STANDARD:-

British Standard: BS EN 12350 \ Part 8 - 2010

TOOLS AND EQUIPMENT:-

1- Mold: As shown in Fig-1, The test specimen shall be formed in a mold made of metal not readily attacked by the cement paste. The metal shall not be thinner than 0.060 in. [1.5 mm], The mold shall be in the form of the lateral surface of the frustum of a cone with the base 8 in. [200 mm] in diameter, the top 4 in. [100 mm] in diameter, and the height 12 in. [300 mm].

2- Base Plate:  Base plate a shown in Fig-1, is a square plate usually made form plastic, Aluminum, or steel, the surface should be perfectly smooth, and shouldn't readily attacked by cement paste, the surface area should be 900-mm by 900-mm, the plate must rigid and avoid from bending, the surface must be tough. Standard drawing should be draw on the top surface of the plate,  two longitudinal line drawn perpendicular to each other, the intersection point should be at the center of the plate, two circle was drawn at the center of the plate with 210±1-mm and 500±1 mm respectively, the thickness of the line shouldn't more than 2-mm and depth of line shouldn't more than 1-mm.

Fig-1: Slump cone and Base plate

3- Weighted Collar: collar as shown in Fig-2, is a relatively funnel shape, made from steel, the mass of collar approximately reach to 9-Kg, collar can help the test operator in two important side, first; help to place the concrete into slump cone easily, and second; help the operator to perform the test alone and exert the downward pressure on the slump cone due to its weight to avoid moving or lifting the cone due to concrete pressure.

Fig-2: Weighted Collar

Note 1:-There is some kind of (Lightweight collar) as shown in Fig-3 which may be used for this test, but in this case the mold should fix by standing over the foot pieces.

Fig-3: Lightweight Collar

4- Ruler or Measuring Device (Tape or whatever mean).

5- Dampen Cloth.

6- Deep Bucket: Suitable bucket must have a sufficient size in which the total test material can be handling. 

7- Stopwatch: stop watch require for timing purposes, must have sensitivity for 0.1 second.

8- Spirit Level: used for ensure that the base plate is perfectly level.

SAMPLE PREPARATION:-

Test specimen can be prepared according to: BS EN 12350 \ Part 1

TEST PROCEDURE:-

1-Place the base plate on the flat and horizontal surface, it should be free from any vibration source, by using spirit level check the top surface for horizontality in both X-Y direction, as shown in (Fig-4).

Fig-4: Checking horizontality for base plate

2-Clean and dampen the cone and base plate by using  a pieces of moisturized cloths as shown in (Fig-5), but the inner surface of the mold and top surface of base plate should be free from excess water.

Fig-5: Dampen and Cleaning base plate and slump cone

3-Place the mold on the base plate centrally within the inner circle which is drawn on the base plate, the mold should be fix by standing over the foot pieces in case of using (lightweight collar) (Note 1), or by using (Weighted Collar), as shown in (Fig-6).

Fig-6: Fix cone on its position

4-As shown in (Fig-7),fill the cone in one operation with out any mechanical compaction or agitation (Note 2), strike off the surplus from the top of the cone, the concrete should stand for 30 seconds in the mold, during this time remove any spilled concrete from the base plate.

Fig-7: Concrete Placing

Note 2:-Self compact concrete (SCC) no need for mechanical compaction during casting in site, that is why the test should reflect the site situation and self compaction concrete properties.

5-As shown in (Fig-8), Lift the cone vertically during 1-3 seconds, this step should perform directly after completing 30 seconds rest in (Step-4), if (T500) is requested start stop watch immediately once the cone leave the base plate and stop the stopwatch once the concrete reach to outer circle which is 500-mm in diameter.

Fig-8: Rising slump cone

6- Once the concrete has been stabilized, measure the largest diameter of flow spread and record as (d1) to the nearest 10-mm, measure the diameter of flow spread right angle to the (d1) and record as (d2) to the nearest 10-mm, as shown in (Fig-9).

Fig-9: Measuring diameter of flow spread

Note 3:- If the difference between (d1) and (d2) greater than 50-mm another sample should be tested and repeat the test procedure. If the result of two consecutive test showing the difference between (d1) and (d2) greater than 50-mm, this is mean the flowability of mixture its not suitable to be a self compact concrete, the mixture should be re-designed.

Note 4:- Check the sign of segregation after completion the test, the sign of segregation is a ring of cement paste\mortar with out coarse particles in the central area of flow spread.

RESULT AND CALCULATION:-

By using (eq-1) Slump flow (SF) can be determined, the (SF) is the average flow diameter.

SF = (d1+d2)/2     (eq-1)

TOLERANCE AND TEST PRECISION :-

According to (Table-1) the result of two tests for similar concrete specimen can be compared with standards.

 

Table-1: Tolerance and Test Precision

REPORT:-

The following information should be written on the test report:

1-Date and time of sampling.

2- Date and time of testing day.

3- Name of tester.

4- Result of T500 if recommended by the client.

5- Result of (d1) and (d2) and (SF).

6- Segregation sign.

The following optional information can be mentioned on the test report:

1-Name of project and Concrete supplier.

2-Name of laboratory.

3-Testing location (Field or Laboratory).

4- Time of testing.

5- Some information about mixture and mix proportions.

6-Temperature of concrete during testing.


REFERENCE:-

1-British Standard: BS EN 12350 \ Part 8 - 2010

 


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WRITER PROFILE:-

BALEN ZRAR ABDULSAMAD

BSc- Geotechnical Engineering\Koya University

MSc- Infrastructure Engineering\ Szechenyi Istvan University


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