Civilengineering-Ideas: lab reports

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                Consistency Test</h2>
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 Scope: 
 
              This method applies to
common cements only. It may not apply to cements types e.g; which have a very
short initial setting time. 
 
Principle: 
 
          Cement paste of standard consistency has a specified
resistance to penetration by a standard plunger. The water required for such a
paste is determined by trail penetrations of pastes with different water
contents. 
 
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Apparatus:</h2>

 
 
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1. Vicat Apparatus:              </div>

                                                 
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           The plunger shall be of a non-corrodible metal in the
form of a right cylinder of at least 4 45 mm effective length and of 1000 mm
diameter. The total mass of the moving parts shall be 300g. 
                                 The mould containing the
paste under test shall be of hard rubber, plastic or brass. It shall be of
cylindrical or preferably truncated conical form 400mm deep and shall have an
internal diameter of 75-85mm. 
                                   The base plate should be
at least 25 mm thick and larger than the mould. 
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2. Balance: 
Capable of weighing
to an accuracy of 1g. 
 
3. Graduated cylinder: 
Capable of dispensing to an accuracy of 1 ml. 
 
4. Timer: 
Capable of measuring to an accuracy of 1 s. 
 
5. Mixer, Ruler and Distilled water: 
 
Procedure: 
 
1.     Take
500 g of cement and a quantity of water e.g.; 125 g 
2.     Mix
each batch of paste mechanically using a mixer. 
3.     Immediately start the mixer at low speed
whilst starting the timing of the mixing stage.         In addition, record the time to
the nearest minute as ”zero time”. 
4.     Stop
the mixer after 90 s and remove all the paste by a suitable rubber or plastic implement and         place it in         a bowl. 
5.     Now fill
the paste with the mould. Remove any voids in the cement paste by gently
tapping 
        and level the surface of the
paste with a straight edged implement. 
6      Adjust the Vicat Apparatus at its
zero reading. 
7.     Place the mould in the center of
Vicat Apparatus under the plunger. 
8.     Lower the plunger gently until it is in
contact with the cement paste. 
9.     Allow the plunger to penetrate and
take reading after 30 s of releasing the plunger. 
10.   This reading indicates the distance
between the bottom face of the plunger and the base plate. 
 
Note: 
Zero Time is the point from where initial and final setting times are measured. 
 
 
 
Observation and
Calculations: 
 
Cement type = Sulfate Resistant 
 
 
Room conditions: 
 
Temperature = 30 C 
Relative Humidity = 80 % 
Weight of water sample = 500 g 
 
Trial no. 1: 
                Water  = 25 % of
the weight of cement 
                     = 125 ml 
Reading measured by the Vicat apparatus = 20 mm 
 
As the above value
is greater than the standard value of 6-8 mm 
So, I order to increase the penetration of water we have to increase the water percentage
that is used in the cement paste. 
 
Trial no. 2: 
            Water =  30 % of the weight of cement                       = 150 g 
Reading measured by the Vicat apparatus = 4 mm 
 
So Standard Consistency
of this cement will be 30%. 
 
<div style="text-align: left;">
 It is used to <a href="http://civilengineering-ideas.blogspot.com/2015/10/how-to-determine-soundness-of-cement.html" target="_blank">determine the soundness of cement</a>.</div>

 
Limitations: 
 The room temperature
should not be more than 20-22 C otherwise it will not give accurate results. <o:p></o:p></div>
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How to determine the consistency of cement?

Consistency Test Scope: This method applies to common cements only. It may not apply to cements ty...

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How to determine the soundness of cement? 
 
                                      Soundness Test 
Scope: 
             This method applies to common cements only. It may not
apply to cements types e.g; which have a very short initial setting time. 
 
Principle: 
          The soundness is determined by observing the volume expansion
of cement paste of <a href="http://civilengineering-ideas.blogspot.com/2015/10/how-to-determine-consistency-of-cement.html" target="_blank">standard consistency</a> as indicated by the relative movement
of two needles. 
 
Apparatus: 
 1. Le Chatelier Apparatus 
                      It consists of a mold
which is made up of a non-corrodible spring metal e.g; brass and having a
radius of 30 mm and thickness of 0.5 mm and two indicator needles having a length
of 150-165 mm. The resilience of the mold shall be such that the action of a
mass of 300 g applied shall increase the distance between the indicator needles
by not less than 150 mm without permanent deformation. 
 
2. Water Bath 
              With means of heating
capable of raising the temperature of the water from 20C to boiling in 30
minutes. 
 
3. Humidity Cabinet               Maintained at 20C and 90% relative humidity. 
 
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                               <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOpWC_yc9Ulbv8_6v3EUg1k4xUoFMCLUbi-D4XxBPaL77FmM0w3YxT3MI9JcsJttOYqA3QbmY38hHH3JBE7DbYEDpisKdO95v-2a61GOJTVnUhyu-9MURM26NY2ekpA-zUvMRdwHuZVJ0/s1600/Le-Chatelier%2527s+Apparatus1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="355" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOpWC_yc9Ulbv8_6v3EUg1k4xUoFMCLUbi-D4XxBPaL77FmM0w3YxT3MI9JcsJttOYqA3QbmY38hHH3JBE7DbYEDpisKdO95v-2a61GOJTVnUhyu-9MURM26NY2ekpA-zUvMRdwHuZVJ0/s400/Le-Chatelier%2527s+Apparatus1.png" width="400" /></a> 
 
Note: 
     1.   Loops shown on
each side of the central split facilitates demolding of the hardened paste   specimen after test. 
    2.   A pair of base and cover plates of
impermeable material, non-corrodible by cement paste shall be provided for each
mold. Each plate shall be larger than the mold. The cover plate shall weigh
at least 75 g. 
 
Procedure: 
  1.    
Prepare a cement paste of standard consistency and fill the cement paste
in the Le Chatelier mold using your hands and level the top of the surface of
the mold with a straight-edged implement. 
 2.     
Cover the mold with a glass plate and place weight over it. 3.       Place this assembly in the
humidity cabinet at temperature of 20C and 90% humidity. 4.       Measure A = Distance between the
indicator points/needles after 24 hours period. 5.       Heat the mold at boiling and
keep it in water for 3 hours at boiling temperature. 6.       Measure B = Distance between the
indicator points/needles after 3 hours. 7.       Allow the mold to cool at room
temperature and measure C = Distance between the indicator 
          points/needles after cooling. 
 
                                    Soundness =   C – A 
Note: 
    Specification Limit for cement is 10 mm. If the soundness value
exceeds this limit than a retest should be done. 
      Retest can be done on the fresh
cement after storing it for 7 days in an atmosphere at 20C and not less than 50% humidity. Then retest the cement. 
 
Calculations: 
 A = 17 mm 
B = 13 mm 
Soundness = C – A = 17-13 = 4 mm 
Soundness value is 4 mm < 10 mm. This indicates that expansion is less and
there will be less chances of cracking .If the value comes out to be greater
than 10 mm than this cement can’t be used because it will have excessive
cracking. 
 
Results:       For a paste of <a href="http://civilengineering-ideas.blogspot.com/2015/10/how-to-determine-consistency-of-cement.html" target="_blank">standard consistency</a>
we measured C-A which came equal to 4 mm and less than the standard
specification limit of 10 mm. Hence we can say that this cement is sound. 
 
 
 
 
<o:p></o:p></div>
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How to determine the soundness of cement

How to determine the soundness of cement? Soundness Test Scope: This method ...

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