To study the effect of water cement ratio on the slump of concrete

To study the effect of water cement ratio on the slump of concrete.

1.      Eqpt/Material  

Slump cone with base dia 8’’, and height 12” with foot pieces and for lifting.Metal plate, tamping rod, steel rule, towel, aggregate. Water and cement.

2.      Procedure:

a.       Place the slump cone on the metal plate and prepare the concrete mix.

b.      Hold the mold on the metal surface firmly. From the sample of concrete fill the mould in three layers each approx 1/3 of the volume of the mould.

c.       Ensure symmetrical distribution of concrete while placing concrete inside the mould.

d.      Give 25 strokes of tamping rod uniformly distributed over the entire cross-section penetration into the underlying layer. The bottom layer shall be rodded of mould its depth.

e.       The mould is then immediately removed by raising it carefully in vertical direction.

f.       Measure the slump by the determining the difference between the height of mould and the specimen after subsidence.

3.       Precaution:

The mould should be removed by raising it carefully in vertical direction without any jerk.

4.      Details if readings and obsns/data to be recorded.

a.       Concrete mix proportions                   =  1:2:4

b.      Water cement ratio                              =  D-5

c.       Type of slump

(1)   True slump            = 5 inch

(2)   Collapse slump      = 6-10 inches

(3)   Shear slump           = 6 inches

5.      The Performa/Format for the prep with the record of obsns, data, with the notes to helps its completion.

S/No.	Slump (Inches)	Water cement Ratio
1.
2.

6.      Interpretation/collation of the obsns readings, graphs, etc leading to results.

To be above with the standard specification of ASTM C 143-78

7.      Comments

a.       With increase in W/c ration increase

b.      The slump and vice versa.

After the prescribed number of revolutions the material shall be discharged from machine and shall be sieved on 1.7mm (#12) sieve.

Calculation

a.       Total weight of sample before test                 = W1

b.      Weight of sample passing sieve # 12              = W2

c.       Abrasion value of Aggregate                          = W21 x 100

                                                                           W1

8.      Specification

a.       Base Coarse    = Less than 45 (%)

b.      Wearing Coarse     = Less than 30 (%)

6.   Reference

            ASTM C 131-89, AASHTOT: 96-87