The Standard & Modified Proctor Density Tests

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1 Revise 2003, WKS Datasheet No. 7 OHAWK COLLEGE OF APPLIED ARTS AND TECHNOLOGY BUILDING AND CONSTRUCTION SCIENCES DEPARTENT The Stanar & oifie Proctor Density Tests INTRODUCTION: In placing fill, it is often necessary an esirable to compact the fill to assure that the soil has sufficient shear strength, that it ill not settle excessively or both. In the fiel various machines are use to carry out the compaction such as sheepsfoot rollers, rubber-tire rollers, etc. These compact the soil to varying egrees epening on the efficiency of the roller for the particular soil, the number of passes, etc. The ensity of the soil can be measure in the fiel by some form of fiel ensity test. The Stanar Proctor Test provies one means of compacting the soil in the laboratory to etermine the optimum moisture content an the maximum ensity. The Stanar test ill be carrie out in the first laboratory session an the oifie test ill be carrie out in the folloing session. The results ill be combine an submitte as one report. The A.S.T.. stanar permits four variations in the test proceure. etho A: 4 inch (101.6 mm) moul (volume 1/30 ft 3 or 1/1060 m 3 ), soil passing a No. 4(4.75 mm) sieve. etho B: 6 inch ( mm) moul (volume 1/13.3 ft 3 or 1/471 m 3 ), soil passing a No. 4(4.75 mm) sieve. etho C: 4 inch (101.6 mm) moul, soil passing a ¾ inch (19.0 mm) sieve. etho D: 6 inch (152.4 mm) moul, soil passing a ¾ inch (19.0 mm) sieve. EQUIPENT (Stanar Test): etho A ill be use in the Stanar test an metho B in the oifie test. In aition to the moul, the folloing equipment ill be require for the Stanar test: a) 5.5 lb (2.49 kg) rammer ith controlle 12 inch (305 mm) rop b) balance sensitive to 1 g. c) balance sensitive to 0.1 g ) 12 inch steel straight ege 1

2 e) mixing tools, pans, moisture containers, etc. f) oven for rying moisture content samples. PROCEDURE (Stanar Test): 1. Either mix 4 kg of san an 400 g of bentonite or if the soil is pre-mixe take about 4½ kg. Break up any lumps in the sample an mix it thoroughly. 2. A about 9.5% ater to the sample or as given by the instructor an mix thoroughly until all the ater is uniformly absorbe. 3. Weigh the empty moul ithout the collar or base an recor its mass. 4. With the collar attache to the moul, compact a specimen in three equal layers to get a total compacte epth of about 130 mm ith 25 uniformly istribute blos of the rammer per layer. During compaction the moul shoul rest irectly on the concrete floor of the lab an not in the mixing pan. 5. Remove the collar from the moul an strike off the soil ith the straight ege even ith the top of the moul. Weigh the moul an the soil an recor their mass. Subtract the mass of the moul from the specimen an multiply by 1060 an recor the result as the et ensity of the compacte specimen in kg/m Remove the soil from the moul using the arbour press. Obtain a moisture content sample of about 120 g from the centre of the specimen, eigh an place in the oven to ry. 7. Break up the sample an remix ith the material that as not use in the test an a approximately 2% more ater. Remix an repeat the compaction proceure an obtain the moisture content of the sample. This proceure is repeate again an again until to successive ecreases in the et ensity of the compacte soil are observe. A minimum of 5 points are normally require to plot the moisture ensity curve. CALCULATIONS (Stanar Test): 1 Wet ensity: (The volume of the 4" moul is m 3 ) 1060 = x 1060 = et ensity in kg/m 3 = mass of et soil containe in the moul in kg (oes not inclue the moul) 2

3 oisture content: = s = moisture content in percent = mass of ater in the moisture sample s = mass of the ry moisture sample Dry Unit Weight: = 1 ( + ) = the ry ensity of the soil Zero Air Vois: = the et ensity of the soil = the moisture content of the soil ZAV Gs = 1+ Gs x G s = the specific gravity of the compacte soil (Assume G s = 2.750) = the ensity of ater (1000 kg/m 3 ) = the moisture content of the soil EQUIPENT (oifie Test): 6 inch (152.4 mm) moul, 10 lb (4.54 kg) rammer ith controlle 18 inch (457 mm) rop balance sensitive to 1 g balance sensitive to 0.1 g 12 inch steel straight ege 3

4 mixing tools oven for rying moisture content samples. PROCEDURE (oifie Test): 1. Take g of san an mix ith 600 g of bentonite or if pre-mixe soil is available about 6½ kg. 2. A about 7% ater to the sample or as given by the instructor an mix thoroughly until all the ater is uniformly absorbe. 3. Weigh the empty moul ithout the collar or base an recor its mass. 4. With the collar attache to the moul, compact a specimen in five equal layers to get a total compacte epth of about 130 mm ith 55 uniformly istribute blos of the rammer per layer of the specimen. During compaction the moul shoul rest irectly on the concrete floor of the lab. 5. Remove the collar from the moul an strike off the soil ith the straight ege. Weigh the moul an soil an recor their mass. Subtract the mass of the moul from the specimen an multiply this mass by 471 an recor the result as the et ensity in kg per cubic metre of the compacte specimen. 6. Remove the soil from the moul. Obtain a moisture content sample from the centre of the specimen, eigh an place in the oven to ry. The moisture content sample shoul eigh approximately 100 g. 7. Break up the sample an re-mix ith the material that as not use in the test an a approximately to 2% more ater. Re-mix again an repeat the compaction proceure an obtain the moisture content of the sample. This proceure is repeate again an again until, for to trials, there is a ecrease in the et ensity of the compacte soil. A minimum of 5 points ill be require to plot the moisture ensity curve. CALCULATIONS (oifie Test): 1 Wet ensity The volume of the 6 inch moul is or ( ) m = x 471 = et ensity in kg/m 3 = mass of et soil containe in the moul in kg (oes not inclue the moul) 4

5 oisture content: = s = moisture content in percent = mass of ater in the moisture sample s = mass of the ry moisture sample Dry Unit Weight: = 1 ( + ) = the ry ensity of the soil = the et ensity of the soil Zero Air Vois: ZAV Gs = 1+ G s x G s = the specific gravity of the compacte soil (Assume it as 2.750) REPORT: = the ensity of ater (1000 kg/m 3 ) = the moisture content of the soil The report shall inclue: 1. Tabulate results obtaine in the laboratory on the form poste on the ebsite for both the Stanar an oifie test shoing the calculate values for moisture content an ry ensity an zero air vois ry ensity. 5

6 2. oisture ensity curves for each test shoing the maximum ensity an the optimum moisture content an ZAV curves plotte on to separate graphs; sho only the three highest moisture content values for the zero air vois curve. 3. On a separate graph plot both the oifie an Stanar curves an a zero air vois curve. 4. In the conclusions compare the maximum ensities an the optimum moisture contents obtaine in the to tests. Calculate the value of the ratio of the maximum ry ensities: Stanar oifie max max 5. Compare the shapes of the moisture ensity curves in terms of hether: a) the left han (et) sies of the stanar an moifie curves parallel, b) the right han (ry) sies are parallel to each other an c) the left han (et) sies are parallel to the zero air vois curve? 6