2 labs reports in 12 hours only 2 pages each

Lab 4. Liquid Limit & Plastic Limit Test (Liquid Limit : Lab 6 in 8th, 9th edition, Plastic Limit: Lab 8 in 9th, Lab 7 in 8th ) – Atterberg Limit

– Basic measure of the critical water contents of a fine-grained soil, such as its shrinkage limit, plastic limit and liquid limit.

Liquid Limit(LL) : The moisture content, in percent, at which the cohesive soil will pass

from a liquid state to a plastic state. The moisture content at which it takes 25 drops of the cup to cause the

groove to close over a distance of 13.5 millimetres (0.53 in)

Plastic Limit(PL) : The moisture content, in percent, at which the cohesive soil will pass

from a plastic state to a semisolid state. The moisture content at which a thread of soil will just crumble when

rolled to a diameter of 1/8 in (3.2mm)

– Notes for Liquid Limit Test – Take 3 trials for

Drop count N = 25 to 35 N = 20 to 25 N = 15 to 20

– Add small amount of water to soil mixture. DON’T POUR WATER

Beginning of test End of test

Count the number of blows N until a soil groove closes to 1/2 inch.

– Notes for Plastic Limit Test

Roiling should be stopped when the thread is just starts crumbling. Diameter of rolled thread should be of 3.2 mm diameter. Weights of container, wet soil and dry soil should be taken accurately.

– Lab Report (see section 6.7 and 8.6 in your textbook)

– Results section should include data table, sample calculations for both LL and PL test, graph of moisture content vs. N, and liquid limit(LL) obtained from the graph.

– Calculate Flow Index FI , the magnitude of the slope of the flow line in your graph.

– Estimate the LL using Eq (6.3) with N-value between 20 and 30 in your results.

𝐿𝐿 = 𝑤𝑁 (%) ( 𝑁 25)

0.121 (6.3)

– Compare the values of liquid limit obtained using Eq.(6.3) with those obtained from the graph.(Consider Table 6-2)

– Report the plastic index (PI) and the liquidity index (LI)

– Report the activity(A) of the soil (see Eq.(8.3)) in your textbook in the lab report.