LAB Report 7 - Standard Proctor PDF

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FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA PAHANG

LABORATORY MANUAL

SOIL ENGINEERING LABORATORY ECG263 OPEN-ENDED LAB MARCH – JULY 2019 TITLE OF EXPERIMENT : STANDARD PROCTOR TEST DATE OF EXPERIMENT : 18th March 2019 GROUP

: EC 110 4F

GROUP MEMBERS

: 1. MUHAMMAD HAZIQ B HUSSAIN (2017226658) 2. MUHAMMAD FARIS B HAMZAH (2017207846) 3. NOR SYAHIRAH AQILAH BT MAD SOMIL (2017226816) 4. NOR AISHAH RODZIAH BT MOHD HANAFI ( 2017209934)

LECTURER

:

AINAMARDIA BT NAZARUDIN

LEVEL OF OPENESS

: 1/1

MARKS

COMMENTS

INTRODUCTION

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OBJECTIVE(S)

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METHODOLOGY

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8

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RESULTS

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DISCUSSION

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CONCLUSION

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TOTAL MARKS

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FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA PAHANG

LABORATORY MANUAL

INTRODUCTION : For earthwork construction it is important to compact soils to a dense state so that the soils will attain satisfactory engineering properties. It is also desirable to know the optimum soil conditionsfor compacting a given soil. According to compaction theory, when samples of a soil are compacted at different water contents using the same compactive energy, there is optimum water content at which the soil will reach a maximum dry density. The optimum water content and dry density depend on the soil composition and the amount of compactive energy used. The moisture-density relationship of a soil is a graph of dry density versus water content, for a given compactive effort.

The data points obtained from compacting several samples at different water contents form a smooth curve, called the compaction curve, which is used to obtain the optimum water content and maximum dry density. The two standardized tests in use today, the standard and modified Proctor tests, differ only by the amount of compactive energy. In practice, the standard or modified Proctor test is conducted on a soil. In the Standard Proctor Test, the soil is compacted by a 4.5 kg hammer falling a distance of 30cm into a soil filled mold. The mold is filled with three equal layers of soil, and each layer is subjected to 27 drops of the hammer.

APPARATUS : 

Standard proctor mould (±1000 ml volume)



Rammer (weight 2.5 kg and dropping height 300 mm)



Oil



20 mm and 37.5 mm sieve



Mixing equipment



Steel straight edge



Moisture can



Sample extruder



Thermostatically controlled oven



Proctor’s needle

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FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA PAHANG

LABORATORY MANUAL

PROCEDURE : 1. About 20 kg of representative dried soil sample passing on 37.5 mm or 20 mm sieve were taken. 2. Water were added on soil sample to bring its water contain to about 7% or less than the estimated optimum moisture content. 3. The mould and the base plate were cleaned. It were fitted and the mass were taken. 4. Grease were applied inside of the mould.

5. The collar of the mould were attached. 6. The matched soil were remixed. About 2 to 3 kg of soil were taken. It was compacted in the 1000 ml mould in 3 equal layers, using the rammer at 27 blows per layer.

7. The collar were removed. excess soil were cut using the straight edge. The penetration resitance of the compated soil were determined using proctor’sneedle and the resitance were recorded needle and the resitance recorded.

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FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA PAHANG

LABORATORY MANUAL

8. The mould were cleaned from outside and weight were recorded. 9. The soil from the mould were taken out. The representative soil specimen from the top and the bottom of the mould were taken for water content determination. 10. Step 5 to 10 were repeated about 5 times but with a gradual increments of water content each time by adding sufficient amout of water on the soil.

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FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA PAHANG

LABORATORY MANUAL

RESULT : Specimen Wt. of Mould + Wet Soil (Kg) Wt. of Mould (Kg) Wt. of Wet Soil (Kg) Vol. of Mould (m3) Wet Density (Mg/m3) Container No. Wt. of Wet Soil + Container (g) Wt. of Dry Soil + Container (g) Wt. of Container (g) Wt. of Dry Soil (g) Wt. of Moisture (g) Moisture Content (%) Avg. Moisture Content (%)

1 6.665

2 6.761

3 6.951

4 7.010

5.015

5.015

5.015

5.015

1.650

1.746

1.900

1.959

0.001

0.001

0.001

0.001

1.65

1.75

1.90

1.96

Top a

Bottom b

Top c

Bottom d

Top e

Bottom f

Top g

Bottom h

95.00

76.00

104.00

85.00

93.00

99.00

78.00

85.00

87.43

71.54

94.55

76.85

81.41

87.13

67.08

72.71

23.00

23.00

23.00

23.00

23.00

23.00

23.00

23.00

64.43

48.54

71.55

53.85

58.41

64.13

44.08

49.71

7.57

4.46

9.45

8.15

11.59

11.87

10.92

12.29

11.75

9.19

13.21

15.13

19.84

18.51

24.77

24.72

Dry Density (Mg/m3)

10.47

14.17

19.18

24.75

1.49

1.53

1.59

1.57

Table 1 shows the result for the standard proctor test laboratory

Calculation

For sample 1: 𝜌𝑏 = (𝑤 + 1)𝜌𝑑 1.650 = (0.1047 + 1)𝜌𝑑 𝜌𝑑 =1.49Mg/𝑚3 For sample 2: 1.750 = (0.1417+1) 𝜌𝑑 𝜌𝑑 = 1.53𝑀𝑔/𝑚 3

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For sample 3: 1.900 = (0.1918+1) 𝜌𝑑 𝜌𝑑 = 1.59𝑀𝑔/𝑚3 For sample 4: 1.960 = (0.2475+1) 𝜌𝑑 𝜌𝑑 = 1.57𝑀𝑔/𝑚3

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LABORATORY MANUAL

DATA ANALYSIS:

Figure 1 shows the graph plotted for the standard proctor test result

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LABORATORY MANUAL

DISCUSSION :

For the discussion, we need to discuss about the error that occurs from the laboratory that we have done. To achieve this using the proctor compaction test we need to know the dry unit weight. We are given 2kg of dried soil sample passing on 37.5mm sieve. This laboratory is to determine the compaction characteristics of soil sample. Compaction of soil is the process in which a stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water being displaced from between the soil grains, then consolidation has occurred. Normally, compaction is the result of heavy machinery compressing the soil. Many errors could have occurred while performing the lab test.

The most prominent error is human error. Someone could have miss counted while using the hammer or there could have been a miss calculation in the computation of the water needed for the desired water content. Another source of error could be from a hole in the tube used to mix the water and soil. The amount of soil in the mold may not have been exactly, throwing off the calculations. The soil is not compact fully can occur error for our result. To avoid the error, we should measure the volume of water accurately. Then, we need to be more alert and minimize the careless mistakes. We should compact the surface of layer of the soil uniformly and make sure it compact fully so can avoid error. We also need to make sure that we have fully take out the compacted soil from the actual soil so that there is no excess soil available in mould.

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FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA PAHANG

LABORATORY MANUAL

CONCLUSION : In conclusion, we have achieved the objective of this standard proctor test laboratory which is to determine the compaction characteristics of soil sample. This test is performed in order to increase the soil shear strength and to reduce the settlement under working loads. The maximum dry density and its optimum moisture content is obtained from the compaction curve graph. Based on the graph, the maximum dry density achieved is 1.582 Mg/m3 and the optimum moisture content achieved is 19.18 %. This value we obtain when the moisture content is at very high when the soil is compacted to nearly saturation where the air is almost driven out.

The precaution steps were taken care off during conducting this test. Firstly, we ensured to take soil sample based on its size grain require for this test which we have sieved the soil sample using a 37.5 mm sieve. Secondly, we make sure that the fan is switched of while measuring the weight of sample or any apparatus that is needed to be weight in this test. Next, we ensured that we added the sufficient amount of increments of water content for every test repeated in order to achieve the different value of moisture content for each test and to increase the shear strength of the soil. Lastly, after the first layer of compaction, we scratched the top of the layer before adding the next layer of soil to ease the compaction between the first and second layer.

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March – July 2019...