UNIVERSITY OF THE WEST INDIESDEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

SOIL MECHANICS I CVNG 2008Year 2 Semester I

TITLE OF EXPERIMENT: COMPACTION TEST

Alisha Garcia 814000806GROUP CBDATE PERFORMED: 6/10/2015DATE OF SUBMISSION: 23/10/2015

TITLE: Standard Proctor Compaction Test using 3 kg of sharp sand.

TABLE OF CONTENTS

Aim: i. To calculate the optimum moisture content of the compacted soil sample.ii. To obtain through graphical interpretation, the maximum dry density of the soil sample.

ABSTRACT

This experiment was performed to determine the maximum dry unit weight and optimum water content of a soil sample. To do this three kilograms of a sharp sand sample was tested using the standard proctor method. The

Description of Apparatus

IntroductionThe main objective of the Standard Proctor Test is to determine the optimum water content and maximum dry density of a soil sample by applying mechanical energy.Compaction involves the removal of some of the air from partially saturated soils, using mechanical means. Compacting soils increases the bulk density which by definition makes the soil denser because the particles are packed closely together since the volume of air is reduced.

In this experiment, the relationship between moisture content and dry unit weight of a compacted soil sample is examined. Moisture content is defined as the ratio of the mass of water to the mass of soil solids (Craig 2004), that is:Water content (w %) = 100% Furthermore, the degree of compaction of a soil sample is measured by its dry unit weight and is defined as: Dry density (d) = The dry unit weight of the soil is dependent on the water content of the soil and the compactive effort applied to the soil i.e., the amount of mechanical energy in this case the number of tamps applied to the sample with the hammer.

Typically, for a given compactive effort, the compaction curve has a peak value. At this maximum, the water content at which the greatest dry density is achieved is called the optimum water content. In addition, on the same graph, another curve is plotted, known as the zero-air voids (ZAV) curve. Here, the zero-air-voids unit weight is plotted against the water content of the compacted soil. The zero-air voids unit weight represents the maximum theoretical dry unit weight of the soil if all the air has been expelled during compaction and the soil was fully saturated (Craig 2004). It can be computed as follows:Zero air-voids unit weight, zav = [3]In practice, this degree of compaction is not achieved. However, in a comparison between the compaction curve and the ZAV curve can give the degree of saturation of the soil. In civil engineering field, compaction is applied to the construction of highways, embankments, airports and other types of civil infrastructure. In the construction of engineering fills and embankments, loose soil is compacted under certain standard specifications using compactive effort from vibrators, rammers and rollers. This compacted fill material is usually applied at the start of the foundation works. In addition to providing a firm and stronger base for foundations, compacted fill material also improves the bearing capacity of the soil.

Procedure

Results

Tin NumberT2L2D4X5G2

Weight of Tin (g)30.931.23131.131.2

Weight of wet soil and tin 103.5109110.6114.5168.8

Dry weight and tin 101.1104.9104.9105.8155.8

Weight of dry soil70.273.773.974.7124.6

Weight of water2.44.15.78.713

Water content (%)3.425.567.7111.6510.43

Sample Number12345

Weight of sample and cylinder 37953882391039553911

weight of cylinder 1992.41992.41992.41992.41992.4

Weight of sample and cylinder 1802.61889.61917.61962.61918.6

volume of cylinder 931.90931.90931.90931.90931.90

wet bulk density1.932.032.062.112.06

water content 3.425.567.7111.6510.43

dry bulk density1.871.921.911.891.86

Assumed Moisture Content 3.006.008.0012.0016.00

Zero Air Void Unit- Weight2.502.322.222.041.89

ANALYSISSample Calculations:diameter of compaction mold, d= 10.105cm radius of mold, r=5.0525cmheight of mould, h= 11.62cm

From Table 1: L2weight of the tin D4 = 31 g... eq'n 1weight of tin and wet soil sample = 110.6 g... eq'n 2 weight of dry soil and tin = 104.9 g... eq'n 3 weight of dry soil = [3] - [1] = 73.9 g... eq'n 4 weight of water = [2] -[3] = 5.7... eq'n 5 Water content of compacted soil, w% = w% = moisture content of sample 3 = 7.71%

From Table 2:weight of cylinder (compaction mould) = 1992.4g... eq'n 6weight of cylinder and wet compacted soil = 3795g... eq'n 7weight of dry soil sample and cylinder = 1802.6...Volume of cylinder = r2h= 931.9... eq'n 8wet bulk density= = 1.93g/cm... eq'n 9

Unit wet weight of soil, = = = 1.87 g/cm3

Zero-air-void unit weight determination: Assumed moisture content soil, w% = 3 % The specific gravity of soil solids, Gs = 2.70 Unit wet weight of water w = 1g/m3 Zero- air-void unit weight, zav = zav = = 2.5 g/cm3

Discussion

Conclusion

References

Appendix

INTRODUCTION

Compaction is the most important activity in the early stages of construction and in any project involving earth works since it is primarily used to improve the engineering properties i.e. the strength properties of the soil. It is a common technique used in field practices owing to its simple methodology and fairly accurate results. Compaction is defined as the densification and