LIME-FLY ASH (LFA) STABILIZATION OF PAVEMENT SUBGRADE SOILS

1. IDAHO STATE UNIVERSITY COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL ENGINEERING LIME-FLY ASH (LFA) STABILIZATION OF PAVEMENT SUBGRADE SOILS Research sponsored by IDAHO TRANSPORTATION DEPARTMENT Prepared by Meron Y. Araya Praveen Katamanin Advisors Dr Manoocher Zoghi (Chair of Civil & Environmental Engineering Dept, ISU) Dr Jim Mahar (Prof) Dr Arya Ebrahimpour (Prof) April 8, 2009

2. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL Presentation Outline Introduction Scope of Work Research Soil Characterization Soil Stabilization Methodology Results Conclusions and Recommendations IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

3. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 1. Introduction History of Development Lime (CaOH, CaO) Fly Ash (Class C, Class F) IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

4. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 2. Background Lime stabilization Fly Ash stabilization Lime-Fly Ash (LFA) stabilization Reduced Plasticity Higher strength Increased CBR values Lower thickness of pavement IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

5. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 3. ResearchSoil Characterization Geologic setting of Eastern Idaho Soil properties based on USDA soil Survey McDole Series Research Soil Silt soil Other Soil units in Pocatello Pocatello Silt loam Delphic Silt IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

6. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL ResearchSoil Characterization, Cont’ • Idaho soil distribution dominated by Silt soil • Research soil is representative of Southeast Idaho soil distribution • Best suited soil for LFA stabilization IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

7. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • Location of the site Courtesy City of Pocatello IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

8. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • Location of the site Courtesy City of Pocatello IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

9. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 3. ResearchSoil Characterization Soil properties considered Plasticity Index (PI) Proctor Compaction test Gradation Soil PH Unconfined Compression Test (UCC) California Bearing Ratio (CBR) IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

10. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

12. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • Summary of Properties of Untreated Soil • Very deep and well drained • Wind-blown deposits • Slope/stream wash on to Flood plain • Liquid Limit ranges between 20 to 30% • Plasticity Index ranges between 5 to 12% • Soil classified as ML/A-7-6 • Low plasticity soil IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

13. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • Summary of Properties of Untreated Soil • Low active clay content • Fairly low undrained shear strength • Alkaline • Low strength soil • Susceptible to moisture content change • Ideal for Lime-Fly ash treatment IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

14. IDAHO STATE UNIVERSITY COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL ENGINEERING 4. Soil Stabilization Mechanism of stabilization Pozzolanicreation of pozzolans (Al2O3, SiO2) with lime (CaOH, CaO) in the presence of water Lime and Fly Ash Proportion Lime to Fly Ash ratio – 1:2 and 1:3 Lime-Fly Ash percentage by dry weight LFA – 2%, 3%, 4%, 6%, 8%,10% and 12% IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

15. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 4. Soil Stabilization Soil properties considered Plasticity Index (PI) Proctor Compaction test Soil PH Unconfined Compression Test (UCC) California Bearing Ratio (CBR) Subgrade Modulus – R Value IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

16. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 5. Results and Conclusion Atterberg Limit Test

17. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • 5. Results and Conclusion • Standard Proctor Compaction Test Figure 3 – Standard Proctor Compaction Curve for treated and Untreated Soil IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

18. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • 5. Results • Soil pH Test IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

19. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • 5. Result • California Bearing Ratio (CBR) Test IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

20. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 5. Result IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

21. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 5. Result, cont’ IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

22. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL 5. Result, cont’ IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

23. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • 5. Results, cont’ • Correlation between CBR and Subgrade Modulus IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

24. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • 5. Result, cont’ • Correlation between CBR and Subgrade Modulus NOTE – Correlation between CBR and R-value was made based on: CBR = 1500 Mr Mr = 1155 + 555 R (Papaginannakis, 2008) (Pavement Design and Materials) Figure 4 Correlation Curve among LFA percentage, Unsoaked CBR and R-Value IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

25. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • Conclusions and Recommendations • LFA stabilization increased CBR value significantly • Improve soil strength • Reduces Plasticity • Reduced pavement thickness • Improved Subgrade Modulus values IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

26. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL • 6. ConclusionandRecommendations, cont’ • LFA stabilization (CBR > 16) • Lime stabilization (CBR > 21) • Fly Ash stabilization (CBR > 23) • Economic impact • Environmental impact • Type of soil • Purpose of stabilization • Availability of materials IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING

27. LIME-FLY ASH STABILIZATION OF SUBGRADE PAVEMENT SOIL Thank you !! Questions ? IDAHO STATE UNIVERSITY, COLLEGE OF ENGINEERING DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING