CE 412

GEOTECHNICAL ENGINEERING 1: SOIL MECHANICS

LAB 10: MODIFIED PROCTOR

COMPACTION TEST

Lab Date : December 1, 2017

Report Date: December 5, 2017

Teaching Assistant: Engr. Cristina Amor M. Rosales

Lab Group : Group 2

Lab Partners : Ilao, Seth Joshua M.

Ingalla, Samantha Abigail M.

Labaguis, Czarah Mercede P.

Mancol, Rose Marie M.

Masilang, Marry Claire F.

Paglicauan, Rebecca B.
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 ABSTRACT

Soil Compaction is the process in which stress is applied to a soil which causes

densification as the voids are filled with solids. This plays a vital part in construction for soils are

mainly used as supports for a lot of infrastructures. Compaction is greatly affected by soil type,

moisture content, and compaction effort and is usually test using ASTM D698. In this report it is

concluded that the soil sample reaches its highest compact state when the dry unit weight is as its

maximum value of 16kN/m3 and 15% moisture content.

This laboratory test is performed to determine the relationship between the moisture

content and the dry density of a soil for a specified compactivity effort. The compactive effort is

the amount of mechanical energy that is applied to the soil mass. Several different methods are

used to compact soil in the field, and some examples include tamping, kneading, vibration, and

static load compaction. This laboratory will employ the tamping or impact compaction method

using the type of equipment and methodology developed by R. R. Proctor in 1933, therefore, the

test is also known as the Proctor test.

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 TABLE OF CONTENTS

1. ABSTRACT…………………………………………………………………………………………….2

2. OBJECTIVES…………………………………………………………………………………………..4

3. THEORETICAL BACKGROUND…………………………………………………………..……....4

4. MATERIALS AND EQUIPMENT…………………………………………………………………...6

5. EXPERIMENTAL PROCEDURES………………………………………………………………....7

6. ANALYSIS OF DATA, DISCUSSION OF RESULTS………………………………….……….......9

7. CONCLUSIONS AND RECCOMENDATIONS……………………………………………………12

8. REFERENCES………………………………………………………………………………………...12

9. APPENDICES……………………………………………………………………………………......12

A. INDIVIDUAL DISCUSSIONS AND CONCLUSIONS………………………………17

B. PICTURES……………………………………………………………………………....20

LIST OF TABLES

TABLE 1: MODIFIED PROCTOR DATA……………………………………………………………. 9

FIGURE 1: FLOW CURVE FOR ………………………………………………...…10

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 OBJECTIVES

1. To measure and determine the optimum water content of a sample of soil.

2. To determine the relationship between the moisture content and the dry density of a soil

for a specified compactive effort using modified proctor test.

THEORETICAL BACKGROUND

In the preceding chapter, we have seen that water generally acts as a lubricant between

solid particles during the soil compaction process. Because of this, in the initial stages of

compaction, the dry unit weight of compaction increases. However, another factor that will

control the dry unit weight of compaction of a soil at a given moisture content is the energy of

compaction. For the standard Proctor compaction test, the energy of compaction can be given by

(3 𝑙𝑎𝑦𝑒𝑟𝑠)(25 𝑏𝑙𝑜𝑤𝑠⁄𝑙𝑎𝑦𝑒𝑟𝑠)(5.5 𝑙𝑏)(1 𝑓𝑡⁄𝑏𝑙𝑜𝑤 ) 𝑓𝑡 . 𝑙𝑏

= 12,375 (593 𝑘𝐽⁄𝑚3 )
1⁄ 𝑓𝑡³ 𝑓𝑡³
30

The modified Proctor compaction test is a standard test procedure for compaction of soil

using a higher energy of compaction. In this test, the compaction energy is equal to

𝑓𝑡. 𝑙𝑏
56,250 (2694 𝑘𝐽⁄𝑚3 )
𝑓𝑡³

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 MATERIALS AND EQUIPMENTS

 Compaction Molds

 No. 4 U.S. sieve

 Mixing dishes

 Spatula

 Balance Sensitive up to 0.01 g

 Balance Sensitive up to 0.1 g

 Large flat pan

 Drying Oven

 Straight Edge

 Water

 Modified Proctor hammer (10 lb)

 Moisture cans

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 EXPERIMENTAL PROCEDURES

1. Obtain about 26.5 lb (12 kg) of air-dry soil on which the compaction test is to be

conducted. Break all the soil lumps.

2. Sieve the soil on a No.4 U.S. sieve. Collect all of the minus-4 material in a large pan.

This should be about 22 lb (10 kg) or more.

3. Add enough water to the minus-4 material and mix it in thoroughly to bring the moisture

content up to about 5%.

4. Determine the weight of the Proctor mold + base plate (not the extension), W1 (lb).

5. Now attach the extension to the top of the mold.

6. 'Pour the moist soil into the mold in three equal layers. Each layer should be compacted

uniformly by the standard Proctor hammer 25 times before the next layer of loose soil is

poured into the mold.

7. Remove the top attachment from the mold. Be careful not to break off any of the

compacted soil inside the mold while removing the top attachment.

8. Using a straight edge, trim the excess soil above the mold. Now the top of the compacted

soil will be even with the top of the mold.

9. Determine the weight of the mold + base plate + compacted moist soil in the mold, W2

(lb).

10. Remove the base plate from the mold. Using a jack, extrude the coma<; ted soil cylinder

from the mold.

11. Take a moisture can and determine its mass, W3 (g).

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12. From the moist soil extruded in Step 10, collect a moisture sample in the moisture can

(Step 11) and determine the mass of the can + moist soil, W4 (g).

13. Place the moisture can with the moist soil in the oven to dry to a constant weight.

14. Break the rest of the compacted soil (to No.4 size) by hand and mix it with the leftover

moist soil in the pan. Add more water and mix it to raise the moisture content by about

2%.

15. Repeat Steps 6 through 12. In this process, the weight of the mold + base plate + moist

soil (W2) will first increase with the increase in moisture content and then decrease.

Continue the test until at least two successive down readings are obtained.

16. The moist soil has to be poured into the mold in five equal layers. Each layer has to be

compacted by the modified Proctor hammer with 25 blows per layer.

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 ANALYSIS OF DATA

Table:

Test No. 2 3 4 5 6
1

Mass of mold (g) W1 1788.6 1789.4 1789.4 1788.6 1789.4

1820.7

Mass of mold and moist soil

3562.3 3510.1 3493.1 3440.7 3435.4
(g) W2 3526.8

Mass of moist soil (kg) W2 –

1.7737 1.7207 1.7037 1.6521 1.646
W1 1.7061

Moist unit weight, (kN/m3)

𝑤2 − 𝑤1 18.45 17.89 17.72 17.18 17.12

𝛾= 17.74
1⁄30

Mass of empty, clean can (g)

5.3 20.6 20.6 5.3 20.6
W3 54

Mass of can and moist soil (g)

34.5 46.7 73.7 87.6 67.7
W4 517

Mass of moist soil (g) Wm 29.2 26.1 53.1 82.3 47.1

463

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Mass of can and dry soil (g)
30.8 42.3 63.4 71 57.4
W5 461

Mass of dry soil (g) Wd 25.5 26.1 53.1 82.3 47.1

407

Water content, 𝑤 =
𝑤4 −𝑤5 14.51 20.28 24.07 25.27 27.99
𝑥 100 13.76
𝑤5 −𝑤3

Dry Unit Weight, (kN/m3)

𝛾 16.11 14.88 14.28 13.72 13.37
𝛾𝑑 = 𝑤
15.60
1+
100

Specific Gravity 2.61 2.61 2.61 2.61 2.61

2.61

Weight of the moist soil (kN) 17.40 16.88 16.71 16.21 16.15
16.74

Volume (cm3)
0.0009433

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Figure 1: Flow Curve of Dry Unit Weight and Zero Air Void Unit Weight using Modified
Proctor Test

25

20
DRY UNIT WEIGHT (KN/M3)

15

Yzav
10 DUW(kn/m3)

0
0 5 10 15 20 25 30 35
MOISTURE CONTENT (%)

Optimum Moisture Content = 14.54%

Maximum Dry Density = 16.11 kN/m3

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 DISCUSSION OF RESULTS

The main purpose of compacting soils is to reduce subsequent settlement underworking

loads. Compaction also increases the shear strength of the soil, reduces voids ratio making it

more difficult for water to flow through soil and prevent the buildup of large water pressures that

cause soil to liquefy during earthquakes. Thus, it is essential to identify the maximum unit

weight of the soil in order to maximize the usages mentioned above through identifying the

quantities or qualities of the factors that affect compaction such as water content, the type of soil

being compacted, and the amount of compactive energy that was used.

Looking back on the previous laboratory report, the soil sample was described to be clay

with low plasticity which gives reliability to the results of the experiment and some typical

values.

After performing ASTM D1557, it has been concluded that the maximum dry unit

weight of 16.11 kN/m3 can be achieved using 14.54 % moisture content. The values attained can

be of great use in construction using the test sample if maximum compaction is wanted in order

to support the maximum load possible.

CONCLUSIONS AND RECOMMENDATIONS

***See attached files for the individual summaries, conclusions of the methods of this group.

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 REFERENCES

Das, Braja M. And Nagaratnam Sivakugan. 2017, Fundamentals of Geotechnical Engineering.

5th ed. Phil. Edition: Cengage Learning

American Society for Testing and Materials. ASTM D1557 - 12e1 - Standard Test Methods for

Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3(2,700

kN-m/m3))

APPENDICES

A. INDIVIDUAL DISCUSSIONS AND CONLUSIONS

B. PICTURES

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A. INDIVIDUAL DISCUSSIONS AND CONLUSIONS

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15
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B. PICTURES

Mass of the Mould

Trial 1 & 4 Trial 2, 3, 5

Mass of Plate

Trial 1 & 4 Trial 2, 3, 5

Mass of mould & plate with saturated soil

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Trial 2 Trial 3 Trial 4

Trial 5

Trial 6

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