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This report is about concrete test. There are
several techniques to test concrete. However; this report will explains the
method which is called; slump. The aim of this test is to detect the consistency
and workability of the mixture of concrete. This method is the most common method
in UK because it is easy to do and it is cheaper then the other methods. While
doing this test there are some important things which must be done as British Standards.
For example; the slump cone. The size used in test was same as in the figure
one. Height; 30cm –  bottom diameter; 20 cm
–  upper diameter; 10cm. Furthermore;
tamping rod. The diameter of the temper rod is 16 mm and the length of it is 60
cm.

                                                        

     

                                                  
                                  -Figure
1-

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Before
starting test concrete need to be prepared. While preparing concrete the ratio
of ingredients is important. Especially the ratio of water and cement.
Moreover; the size and the shape of the aggregates also affect the consistency of
concrete While preparing concrete approximately the percentage of coarse
aggregates (gravel) is %43, fine aggregates (sand) %34, cement %15, water %8 and
air. After preparing concrete some equipment are necessary to do this test.
These are; slump cone, rigid metal plate, slump rod, sheet rule, etc. The first
step is mixing all necessary materials in the big mixer which is special for
preparing concrete. After that before starting testing the concrete all equipment
must be cleaned. Moreover; all steps in the figure 2 will be done.

            

                                                
                                  -Figure 2-

 

·        
First picture explains; to fill 1/3 of the slump
cone and by tamping twenty five times all concrete uniformly distributed.

·        
In
second picture 2/3 of the cone filled up and same tamping process performed.

·        
Next
step is filling cone fully and applying same process.

·        
Fourth
step is removing the excess concrete and levelling it with trowel.

·        
Then
the mould is removed by raising it vertically. As removing cone the concrete subsides.

·        
At
the last step; the height of the mould and the highest point of concrete measured
with sheet rule and the subsidence of measured is the slump of the concrete.

 

 

Result
of the test can be true, zero, shear or collapsed like as shown in the figure
3.  

 

 

                                                              
             -Figure
3-

 

 

·        
True
slump: This is the only slump that can be acceptable in the test.

·        
Zero
slump: This slump is dry and generally used in road construction. The reason dry
concrete is very low water :  cement
ratio.

·        
Collapsed
slump: This result is not suitable for the slump test. This concrete is too wet
then expected result and the reason of it is too high water : cement ratio.

·        
Shear
slump: This results is accepted as incomplete or fail.

 

To
calculate the volume of cone ?h/3
(R^2 + Rr +r^2) can be used. Then the
formula of Density= Mass/Volume is used ( density of concrete is 2400kg/m^3 )
then the mass is found. After that the wastage is calculated. Furthermore; as
the ratio of 1:2:4 all FA, CA, Water can be calculated.

 

    

 

 

     On the other hand; there is a test for
harden concrete which is called cube test. Necessary equipment is; concrete
compressive strength machine, mould cube, tamping rod, etc. Mould cube is made up of cast iron or steal and the
size of it is 150mm -150mm – 150 mm.

 

·        
The
first step is preparing concrete.

·        
After
that; cleaning the mould with oil is so important like the other experiment.

·        
Third
step is similar to the slumping test because while filling the cube there are three
steps and between every step every layer must be compacted 35 times with tamping
rod.

·        
Then
the top of the mould levelled and leave it twenty four hours.

·        
After
twenty four hours specimens are removed from the cube.

·        
Then
these concretes will be put in to the water and stayed there at least 24 hours
before testing.

·        
This
concrete test must be applied to the concrete 7 and 28 day age by compressive strength
machine.

·        
The
cube is placed in to the machine.

·        
As
the force applied to the concrete the concrete separate.

 

In
the calculation part to calculate Compressive specimen = Compressive load / Cross-section
area of the specimen.

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