Compaction TestIntroduction“Compaction is the process of increasing the density of a soil by bringing particles closer together with a reduction in air volume.” (Craig, 2004) Compaction tests are important in earthwork construction as the purpose of this test was to find the relationship between the moisture content and dry density of an engineering soil. This information could be used to find the optimal moisture content and maximum dry density. At this maximum dry density value it is also possible to calculate the void ratio, porosity, degree of saturation and air content. Apparatus • Metal mixing bowl • Spatula • Graduated cylinder • 1 liter steel mold with base plate and collar • 2.5 kg compaction rammer • Electronic scales • Additional apparatus for determination of moisture content as described in the BS 1337-2: 1990 o Metal canisters for small samples o Oven for drying samples in canistersMethodThe method used was a standard method for compaction testing using a 2.5 kg rammer described in BS 1377-4: 1990.• Measure 5 kg of soil on the electronic scale and add to the mixing bowl.• Add 250 ml of water to the sample to set the moisture content to 5%, then mix the sample.• Record the mass of the mold with the base plate attached.• Attach the top collar to the mould.• Add enough soil to reach approximately one third of the total height of the mould.• Compact the soil by applying 27 blows with the 2.5 kg rammer distributed evenly over the entire surface of the soil.• Add more two layers of soil, compacting equally, so that the final level of the soil surface reaches approximately 10mm above the top of the mould.• Detach the top collar and remove excess soil so that the surface is level with the upper part of the mold.• Re...... in the center of the paper ......becomes;Sr = ((w/100) x 2.12 x 1000) / VvSr = ((8/100 ) x 2.12 x 1000) / 208.955Sr = 0.812 = 81.2%• Air ContentAir Content = Air Volume / Total VolumeA = VA / VAir Volume can be calculated using the Vv equation = VA +Vw. The volume of water can be calculated knowing that Vw = Mw, Mw = w/100 x Ms and Ms = ρdV. So Vw = 169.6VA = 208.955 – 169.6VA =39.355A = VA / VA = 39.355/1000A = 0.0394 = 3.94%AnalysisThe results show that the compaction test was successful as a correct relationship was established between dry density and moisture content. The inferred values ​​for the maximum dry density and optimum moisture content are within an acceptable range and the calculated air content is in agreement with the air content lines drawn on the graph showing that the air content value at the maximum dry density is between 0% E 5%.