1

Modified

Proctor Test

PUPR

Dec 2000

Rev April 2007 - AMG

Compaction:

Reduction of void ratio by mechanical means.

Soil Compaction:

•Reduces soil compressibility

•Reduces soil porosity – vulnerability to

changes in water content

•Dry density increases soil shear strength

Compaction Equipment Compaction Equipment

2

Compaction EquipmentMix the water thoroughly with 5 lb of

dry, crushed soil in about 3 stages.

Test Specs

Mold Volume, Both Tests:

1/30 ft3 for 4-in Mold

3/40 ft3 for 6-in Mold

Standard

Hammer: 5.5 lbs

Drop: 12 in (1 ft)

# Layers: 3

Blows/Layer: 25 (4in) 56 (6 in)

Modified

Hammer: 10.0 lbs

Drop: 18 in (1.5 ft)

# Layers: 5

Blows/Layer: 25 (4in) 56 (6 in)

Pour the moist soil

into the mold:

5 layers for the

Modified test

3

Apply the

compaction

energyTrim the compacted sample to the mold volume

Record the weight

of the moist soil

plus the mold and

place them in the

sample ejector. Break the compacted sample to

obtain water content sample

4

Obtain at least 500 grams of moist soil from the

center of the sample to determine its water content Place in oven to determine sample water content

γγγγd : Dry Density, = γγγγt / (1+w)

• γγγγt : Total Density, = Wt / Vt

Wt : Wmold+moist sample - Wmold

Vt: Mold Volume

•w = Water Content (decimal value)

Compaction

Curve

Prepare it to fit in an

8-1/2 x 11 sheet

Modified Proctor Test on Sandy Clay

June 12, 2002

98

100

102

104

106

108

110

112

114

116

0 5 10 15 20 25 30

Water Content (%)

Dry Density (lb/ft3)

5

Moisture-Dry density

relationships for

various types of soils

(Peck)

Given:

Mold D = 4 in

Unit Weight:

W mold = 4.50 lbs

W mold+moist soil = 8.60 lbs

Water Content

W moist soil+cup = 670 gr

W cup = 160 gr

W dry soil+cup= 614 gr

Proctor Test Calculation Example:

Total Unit Weight:

γγγγT = (8.60-4.50) lb / (1/30) ft3

γγγγT = 123.0 lb/ft3

Water Content

w = (670-614) / (614-160) x 100

w = 12.4 %

Dry Unit Weight:

γγγγD = (123.0) / (1 + 0.124) = 109.4 lb/ft3

Plot ► w = 12.4 % , γγγγD = 109.4 lb/ft3

Compaction

Curve

Prepare it to fit in an

8-1/2 x 11 sheet

Modified Proctor Test on Sandy Clay

June 12, 2002

98

100

102

104

106

108

110

112

114

116

0 5 10 15 20 25 30

Water Content (%)

Dry Density (lb/ft3)

Moisture-Dry density

relationships for

various types of soils

(Peck)

PUPR CE-4203 Geotechnical Engineering I Lab

MODIFIED PROCTOR TEST DATA

Soil Description: _______________________________________ Date: _________________ Section: _______

TOTAL DENSITY

W mold (lbs) = V mold(D=4in) = 1/30 ft3 = 944 cm3

Water Added (gr)

Wt+mold (lbs)

γT (PCF)

WATER CONTENT & DRY DENSITY Cup No.

Wt+cup (gr)

Wcup (gr)

Wdry+cup (gr)

w (%)

γd (PCF)