Unformatted text preview: calculations if needed 2. Determine the Hygroscopic correction factor (Hcf ) 3. For use in computing the hydrometer analysis and the fine portion of the sieve analysis, the total oven dried hydrometer sample must be calculated first. Calculate this by using the following formula: % . 10 100 where: hs = mass of hydrometer (test) sample Hcf = hygroscopic correction factor M = mass of total hydrometer (test) sample 4. Apply the composite correction value to the actual hydrometer reading taken, this value will be known as R. 5. For hydrometer type 152H, use Table 5 to obtain the effective hydrometer depth L in cm. *note: remember to use the “actual hydrometer reading” to find L, not the composite corrected hydrometer value. 6. For known Gs of the soil (if not known, assume 2.65 for this lab purpose), obtain the value of K from Table 6. Calculate the equivalent particle diameter by using the following formula: DK L
t Winter 2013 8 CIVE 153 – Earth Engineering Hydrometer Analysis Department of
Engineering where: D = particle diameter in (mm), K = hydrometer constant based on the water temperature and viscosity (unit less), L = hydrometer length in the fluid (cm) as shown in Figure 1, and t = lapse time from the start of the test in (mins). 7. Determine the temperature correction CT using Table 7. 8. Determine correction factor “a” using Gs and Table 8. 9. Calculate corrected hydrometer reading as follows: Rc R CT 10. Calculate percent finer as follows: 100 where: M = mass of total hydrometer (test) sample (g) *as determined above 11. Adjusted percent fines as follows: 100 where F200 = % finer of #200 (75 µm) sieve as in percent passing obtained from sieve analysis. Results/Reporting Winter 2013 9 Department of
Engineering CIVE 153 – Earth Engineering Hydrometer Analysis
1. Plot the percent finer (PA) versus the particle size (D), (particle size distribution curve). *This graph should be in plotted in log scale. 2. Define the D60, D...
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- Winter '13
- Civil Engineering, hydrometer, hydrometer analysis, Earth Engineering