Calculations

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Calculations

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The following calculations are used in this test:

 

Sieve Cumulative % Passing

 

Cumulative % Passing = 100 * ( 1 - Mc / Ms)

 

where,

Mc        = Cumulative mass retained

Ms        = Dry sample mass

 

 

Hydroscopic Moisture

 

C (%) = 100 * (Ma - Mo) / Mo

 

where,

C        = Hydroscopic moisture

Ma        = Air dried sample mass

Mo        = Oven dried sample mass

 

 

Corrected Oven-Dried Mass

 

W =  (Mhs * Mo / Ma) / (1 + Mr10 / Ms)                        Mass retained on #10 of Total Sample Method        

 

W = 100 * (Mhs - Mr10) / (100 + C)                        Mass retained on #10 of Hydrometer Sample Method        

 

W = 100 * (Mhs / P200) / (100 + C)                        Percent finer than #10 Method

 

where,

W        = Corrected oven-dried mass

Mhs        = Mass of hydrometer sample

Mr10        = Mass retained on #10 sieve

P200        = Percentage finer than #200

 

 

Hydrometer Cumulative % Passing

 

Cumulative % Passing = [(100000 / W) * SG / (SG - SGL)] * (R -SGL)        Hydrometer 151H

 

Cumulative % Passing =        (R * a / W) * 100                                Hydrometer 152H

 

where,

SG        = Specific gravity of soil particles

SGL        = Specific gravity of suspension liquid

R        = Hydrometer reading with composite correction applied

a        = Correction faction

 

 

Washed Sieve Cumulative % Passing

 

Cumulative % Passing = 100 * (Ppf - Mcw / Mtw)

 

where,

Mcw        = Cumulative mass retained on washed sieve

Ppf        = Percent passing final unwashed sieve

Mbw        = Before wash sample mass

Mtw        = Mbw / Ppf (if Mbw specified) or W (if hydrometer specified)

 

 

Washed Mass after Sieving

 

Mcwf = Final Mcw

 

 

Accuracy

 

Accuracy (%) = 100 * (Mcwf - Maw) / Mcwf

 

where,

Maw        = After wash sample mass

 

 

Hydrometer Accuracy

 

Accuracy (%) = 100 * (Mbw / Ppf - W) / W