PROCTOR TEST

SCOPE

This method covers the determination of the relationship between the moisture content and density of soils compacted in a mould of a given size with a 2.5 kg rammer dropped from a height of 30 cm.

 

APPARATUS

  1. Proctor mould having a capacity of 944 cc with an internal diameter of 10.2 cm and a height of 11.6 cm. The mould shall have a detachable collar assembly and a detachable base plate.
  2. Rammer: A mechanical operated metal rammer having a 5.08 cm diameter face and a weight of 2.5 kg. The rammer shall be equipped with a suitable arrangement to control the height of drop to a free fall of 30 cm.
  3. Sample extruder.
  4. A balance of 15 kg capacity.
  5. Sensitive balance.
  6. Straight edge.
  7. Graduated cylinder.
  8. Mixing tools such as mixing pan, spoon, towel, spatula etc.
  9. Moisture tins.

 

PROCEDURE

            Take a representative oven-dried sample, approximately 5 kg in the given pan. Thoroughly mix the sample with sufficient water to dampen it to approximately four to six percentage points below optimum moisture content.

            Weigh the proctor mould without base plate and collar. Fix the collar and base plate. Place the soil in the Proctor mould and compact it in 3 layers giving 25 blows per layer with the 2.5 kg rammer falling through.

            Remove the collar, trim the compacted soil even with the top of the mould by means of the straight edge and weigh.

            Divide the weight of the compacted specimen by 944 cc and record the result as the wet weight gwet in grams per cubic centimeter of the compacted soil.

            Remove the sample from the mould and slice vertically through and obtain a small sample for moisture determination.

            Thoroughly break up the remainder of the material until it will pass a no.4 sieve as judged by the eye. Add water in sufficient amounts to increase the moisture content of the soil sample by one or two percentage points and repeat the above procedure for each increment of water added. Continue this series of determination until there is either a decrease or no change in the wet unit weight of the compacted soil.

 

CALCULATION

            Wet density gm/cc =weight of compacted soil / 944.

            Dry density              = wet density/(1+w)

Where w is the moisture content of the soil.

Plot the dry density against moisture content and find out the maximum dry density and optimum moisture for the soil.

  

OBSERVATIONS

Cylinder diameter                   cm.                                                                                  

a. height                                 cm                                                                                  

b. volume                               cc

weight of cylinder                   gm              

 

                                               

Density

 

 

 

 

 

Determination No.

 

 

 

 

 

Water to be added (percent)

 

 

 

 

 

Weight of water to be added (gm)

 

 

 

 

 

Weight of cylinder + compacted soil

 

 

 

 

 

Weight of compacted soil (gms)

 

 

 

 

 

Average moisture content (percent)

 

 

 

 

 

Wet density

(gm /cc)

 

 

 

 

 

Dry density (gm/cc)

 

 

 

 

 

Water content

 

 

 

 

 

Container No.

 

 

 

 

 

Wt. Of container + wet soil gms.

 

 

 

 

 

Wt. Of container + dry soil gms

 

 

 

 

 

Wt of container alone gms.

 

 

 

 

 

Wt. Of water gm

 

 

 

 

 

Wt. Of dry soil gms.

 

 

 

 

 

Percentage of water

Content

 

 

 

 

 

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