Index Properties and Strength Index Properties and Strength of - - PowerPoint PPT Presentation

Index Properties and Strength Index Properties and Strength

• f Artificial Soil Using the
• f Artificial Soil Using the

Harvard Miniature Method Harvard Miniature Method

Krystal Wilbourn, REU Student Krystal Wilbourn, REU Student Kalaiarasi Vembu, Graduate Mentor Kalaiarasi Vembu, Graduate Mentor & &

• Dr. C., Vipulanandan, Faculty Mentor
• Dr. C., Vipulanandan, Faculty Mentor

Objective Objective

• The overall objective of this research

project was to investigate the relationships between the index properties and strength of artificial soil prepared using the Harvard Miniature Method.

Introduction Introduction

• Compaction characteristics of soil are usually

determined by conducting Standard Procter tests in the laboratory over the soil and the test results are utilized in the field for different construction and also for ensuring the quality of

• construction. However, the test is quite costly

and time consuming

• If the estimation of the moisture-density

relationship could be developed on the basis of some tests which are quick to perform, less time consuming and cheap, then the process will help the constructors enormously

Intro Cont’d Intro Cont’d

• In the present study, moisture-density

relationship from Harvard Miniature compaction method with the help of index properties and compressive strength of the soil was studied.

The The

tests

tests

performed included the unconfined

performed included the unconfined compression test using the Harvard Miniature compression test using the Harvard Miniature apparatus, liquid limit, and plastic limit tests apparatus, liquid limit, and plastic limit tests

Harvard Miniature Apparatus Liquid Limit Test Device Plastic Limit Sample

Materials & Methods Materials & Methods

• A compilation of artificial soil mixtures

were used in varying proportions in order to better observe characteristics

• Mixtures consisted of poorly graded sand

with a specific gravity of 2.65, kaolinite with specific gravity of 2.623 and bentonite with specific gravity of 2.89

Sieve Analysis Sieve Analysis

Sieve Analysis

10 20 30 40 50 60 70 80 90 100 0.0001 0.001 0.01 0.1 1 Particle Diameter, mm Percent Finer, %

Sand Bentonite Kaolinite

Grain size distribution of sand, kaolinite and bentonite

Compaction Test Compaction Test

• Compaction is a process by which the soil

particles are artificially rearranged and packed together into a closer state of contact by mechanical means in order to decrease the porosity of the soil and increase its dry density

Harvard Miniature Compaction Harvard Miniature Compaction

Harvard Miniature compaction apparatus. (A=tamper, B=mold with collar attached to the base, C=device to remove mold collar without tearing last layer, D=sample extruder, E- compacted samples.

Index Properties Index Properties

30K70S 15.77 15.77 CL-ML 50K50S 23.91 15 8.21 CL-ML 70K30S 31.709 22 15.92 CL B10K40S50 68.25 12 56.25 CH B15K35S50 80.816 10 70.85 CH B20K30S50 106.7 14 93.1 CH 30B70S 142.19 18 124.08 CH 50B50S 213.006 27 185.81 CH 70B30S 342.45 36 306.4 CH Plastic Limit (%) Artificial Mixture Liquid Limit (%) Plasticity Index (%) USCS Classific ation

Plasticity Index vs. Liquid Limit Plasticity Index vs. Liquid Limit

PI vs LL 50 100 150 200 250 300 350 400 450 100 200 300 400 500 600 700 Liquid Limit (%) Plasticity Index (%) 100B 100K 30B 70S 50B 50S 70B 30S 30K 70S 50K 50S 70K 30S 10B 40K 50S 15B 35K 50S 20B 30K 50S U Line

Max Dry Density vs. Opt Moisture Max Dry Density vs. Opt Moisture Content Content

200 220 240 260 280 300 320 340 360 10 12 14 16 18 20 22 24 Optimum Moisture Content (%)

• Max. Dry density (pcf)

B, K & S B & S K & S

Max Dry Density vs. Liquid Limit Max Dry Density vs. Liquid Limit

Opt MC vs LL

20 40 60 80 100 100 200 300 400 Liquid Limit (%) Dry Opt Moisture Content (psi) 30B 70S 50B 50S 30S 70B 70S 30K 30S 70K 15B 35K 50S 20B 30K 50S 50K 50S 10B 40K 50S

Max Dry Density vs. Plasticity Index Max Dry Density vs. Plasticity Index

y = -0.1139x + 312.63 R2 = 0.212 50 100 150 200 250 300 350 400 50 100 150 200 250 300 350 Plasticity Index

• Max. Dry density

Optimum Moisture Content vs. Optimum Moisture Content vs. Liquid Limit Liquid Limit

y = 0.0155x + 15.327 R2 = 0.219 5 10 15 20 25 50 100 150 200 250 300 350 400 Liquid Limit (%) Optimum Moisture Content (%)

Compressive Strength vs. Moisture Compressive Strength vs. Moisture Content (K, S) Content (K, S)

10 20 30 40 50 60 70 80 90 5 10 15 20 25 30 Moisture Content % Qu (psi) 30K 70S 50K 50S 70K 30S

Optimum Moisture Content vs. Optimum Moisture Content vs. Plasticity Index Plasticity Index

Opt MC vs PI

20 40 60 80 100 0.00 100.00 200.00 300.00 400.00 Plasticity Index Opt MC 30B 70S 50B 50S 70B30S 30K70S 50K 50S 70K30S 10B 40K 50S 15B 35K 50S 20B 30K 50S

Compressive Strength vs. Moisture Compressive Strength vs. Moisture Content (B, K, S) Content (B, K, S)

10 20 30 40 50 60 5 10 15 20 25 Moisture Content % Qu B10 K40 S50 B15 K35 S50 B20 K30 S50

Compressive Strength vs. Moisture Compressive Strength vs. Moisture Content (B, S) Content (B, S)

10 20 30 40 50 60 10 15 20 25 30 Moisture Content % Qu (psi) 30B 70S 50B 50S 70B 30S

Dry Unit Weight vs. Moisture Dry Unit Weight vs. Moisture Content (B,S) Content (B,S)

Bentonite and Sand

200 220 240 260 280 300 320 340 10 15 20 25 30 Moisture Content % Dry Unit Weight (pcf) 30B 70S 50B 50S 70B 30S

Dry Unit Weight vs. Moisture Dry Unit Weight vs. Moisture Content (K, S) Content (K, S)

Kaolinite and Sand

200 250 300 350 400 450 5 10 15 20 25 30 Moisture Content (%) Dry Unit Weight (pcf) 30K 70S 50K 50S 70K 30S

Dry Unit Weight vs. Moisture Dry Unit Weight vs. Moisture Content (B, K, S) Content (B, K, S)

Bentonite, Kaolinite and Sand

260 270 280 290 300 310 320 8 13 18 23 Moisture Content % Dry Unit Weight (pcf) B10 K40 S50 B15 K35 S50 B20 K40 S50

Conclusion Conclusion

• The liquid limit and plasticity index of artificial

soil increases with increase in clay content and the increase is more pronounced in bentonite/sand and bentonite/kaolinite/sand mixtures

• Max dry density decreases and OMC increases

with increase in bentonite/kaolinite/sand mixtures

• OMC increases with increase in bentonite and

decreases with the increase in kaolinite in bentonite , kaolinite and sand mixtures for the same sand content

Conclusion Cont’d Conclusion Cont’d

• Peak shear strength increases with

increase in clay content except for 50K 50S miture which shows high strength

• In the bentonite, kaolinite and sand mix

B10K40S50 shows high strength

• Relationship between strength and index

properties has been brought out based on the test