A l a s Soil Stabilization Manual k a 2014 Update AD e l ap sa k R. Gary Hicks Ph.D. r at Billy Connor, PE m U Robert L. McHattie, P.E. e n n i vt December 2014 eo rf s iT tr y a Tn rs ap no sr pt a o t ri to an t i& o n P C u eb nl i tc e rF a c i Alaska University Transportation Center Alaska Department of Transportation l i Duckering Building Room 245 Research, Development, and Technology t i P.O. Box 755900 Transfer e Fairbanks, AK 99775-5900 2301 Peger Road s INE/ AUTC 14.16 DOT&PF Report Number 60392(T2-08-16) Disclaimer Notice This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document. 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Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestion for reducing this burden to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-1833), Washington, DC 20503 1.AGENCY USE ONLY (LEAVE BLANK) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED Report No. 60392(T2-08-16) October 2014 Final Report 4.TITLE AND SUBTITLE 5.FUNDING NUMBERS Alaska Soil Stabilization Guide 2014 Update Alaska DOT&PF AKSAS 60392 (T2-08-16) University of Alaska Fairbanks 6.AUTHOR(S) G0005296 R. Gary Hicks Ph. D., Billy Connor, P.E., Robert L. McHattie, P.E. AUTC 207117 7.PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8.PERFORMING ORGANIZATION REPORT Alaska University Transportation Center NUMBER University of Alaska Fairbanks INE/AUTC 14.16 Duckering Building Room 245 P.O. Box 755900 Fairbanks, AK 99775-5900 9.SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10.SPONSORING/MONITORING AGENCY REPORT NUMBER State of Alaska, Alaska Dept. of Transportation and Public Facilities Research and Technology Transfer Report # 60392(T2-08-16) 2301 Peger Rd Fairbanks, AK 99709-5399 11.SUPPLENMENTARY NOTES 12a. DISTRIBUTION / AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE No restrictions 13.ABSTRACT (Maximum 200 words) Soil Stabilization is used for a variety of activities including temporary wearing curses, working platforms, improving poor subgrade materials, upgrading marginal materials, dust control, and recycling old roads containing marginal materials. There are a number methods of stabilizing soils including modifying the gradation, the use of asphalt or cement stabilizers, geofiber stabilization and chemical stabilization. Selection of the method depends on the soil type, environment and application. This manual provide tools and guidance in the selection of the proper stabilization method and information on how to apply the method. A major portion of this manual is devoted to the use of stabilizing agents. The methods described here are considered best practices for Alaska. 15.NUMBER OF PAGES 14- KEYWORDS : Soil Stabilization (Fcbys), Dust Control (Fmbbe) 75 16.PRICE CODE N/A 17.SECURITY CLASSIFICATION OF 18.SECURITY CLASSIFICATION 19.SECURITY CLASSIFICATION 20.LIMITATION OF ABSTRACT REPORT OF THIS PAGE OF ABSTRACT Unclassified Unclassified Unclassified N/A NSN 7540-01-280-5500 STANDARD FORM 298 (Rev. 2-98) Prescribed by ANSI Std. 239-18 298-1 ii SI* (MODERN METRIC) CONVERSION FACTORS APPROXIMATE CONVERSIONS TO SI UNITS Symbol When You Know Multiply By To Find Symbol LENGTH in inches 25.4 millimeters mm ft feet 0.305 meters m yd yards 0.914 meters m mi miles 1.61 kilometers km AREA in2 square inches 645.2 square millimeters mm2 ft2 square feet 0.093 square meters m2 yd2 square yard 0.836 square meters m2 ac acres 0.405 hectares ha mi2 square miles 2.59 square kilometers km2 VOLUME fl oz fluid ounces 29.57 milliliters mL gal gallons 3.785 liters L ft3 cubic feet 0.028 cubic meters m3 yd3 cubic yards 0.765 cubic m3 meters NOTE: volumes greater than 1000 L shall be MASS oz ounces 28.35 grams g lb pounds 0.454 kilograms kg T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t") TEMPERATURE (exact degrees) oF Fahrenheit 5 (F-32)/9 Celsius oC or (F-32)/1.8 ILLUMINATION fc foot-candles 10.76 lux lx fl foot-Lamberts 3.426 candela/m2 cd/m2 FORCE and PRESSURE or STRESS lbf poundforce 4.45 newtons N lbf/in2 poundforce per square inch 6.89 kilopascals kPa APPROXIMATE CONVERSIONS FROM SI UNITS Symbol When You Know Multiply By To Find Symbol LENGTH mm millimeters 0.039 inches in m meters 3.28 feet ft m meters 1.09 yards yd km kilometers 0.621 miles mi AREA mm2 square millimeters 0.0016 square inches in2 m2 square meters 10.764 square feet ft2 m2 square meters 1.195 square yards yd2 ha hectares 2.47 acres ac km2 square kilometers 0.386 square miles mi2 VOLUME mL milliliters 0.034 fluid ounces fl oz L liters 0.264 gallons gal m3 cubic meters 35.314 cubic feet ft3 m3 cubic meters 1.307 cubic yards yd3 MASS g grams 0.035 ounces oz kg kilograms 2.202 pounds lb Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T TEMPERATURE (exact degrees) oC Celsius 1.8C+32 Fahrenheit oF ILLUMINATION lx lux 0.0929 foot-candles fc cd/m2 candela/m2 0.2919 foot-Lamberts fl FORCE and PRESSURE or STRESS N newtons 0.225 poundforce lbf kPa kilopascals 0.145 poundforce per square inc h lbf/in2 *SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003) ii Soil Stabilization Design Guide ACKNOWLEDGMENTS The authors wish to acknowledge the technical support provided by the following Alaska DOT&PF personnel: • Steve Saboundjian—Statewide Pavement Engineer • Tim Wooster—Northern Region • Newt Bingham, Bob Lewis, and Scott Gartin—Central Region • Pat Kemp and Bruce Brunette—Southeast Region They assisted by providing the information needed to evaluate current practices. Thanks also to Fran Petersen and Melissa Sparks who spent hours reformatting the manual. Soil Stabilization Design Guide iii Contents ACKNOWLEDGMENTS ................................................................................................................................ iii Contents ..................................................................................................................................................... iv LIST OF FIGURES ......................................................................................................................................... ix LIST OF TABLES ..........................................................................................................................................10 1.0 INTRODUCTION ........................................................................................................................... 1 1.1 Background ................................................................................................................................. 1 1.2 Scope ........................................................................................................................................... 1 1.3 Limitations ................................................................................................................................... 2 2.0 TYPES OF STABILIZATION ............................................................................................................ 3 2.1 Classification of Stabilization Types ............................................................................................ 3 2.2 Types of Stabilizing Agents .......................................................................................................... 3 2.3 Selecting the Correct Stabilizing Agent ....................................................................................... 6 2.3.1 Soil Type .............................................................................................................................. 6 2.3.2 Climate and Drainage .......................................................................................................... 6 2.3.3 Sampling and Testing .......................................................................................................... 6 2.3.4 Final Selection ..................................................................................................................... 6 2.4 References .................................................................................................................................. 8 3.0 DESIGN PHILOSOPHY .................................................................................................................. 9 3.1 Design Considerations ................................................................................................................. 9 3.2 Materials Mix Design .................................................................................................................. 9 3.3 Structural Design ........................................................................................................................ 9 3.3.1 Unbound Materials ...........................................................................................................10 3.3.2 Bound Materials ................................................................................................................11 3.3.2.1 Cementitiously Bound Material ...................................................................................... 11 3.3.2.2 Asphalt-Bound Material .................................................................................................. 13 3.3.3 Assessment of Existing Pavements or Recycling ...............................................................13 3.3.4 Design Traffic ....................................................................................................................13 3.4 Construction Considerations ....................................................................................................13 3.4.1 Stabilization Equipment ....................................................................................................13 3.4.2 Compaction Equipment ....................................................................................................14 iv Soil Stabilization Design Guide 3.4.3 Procedures and Operations ..............................................................................................14 3.5 References ................................................................................................................................14 4.0 ASPHALT STABILIZATION ...........................................................................................................15 4.1 General .....................................................................................................................................15 4.2 Materials ...................................................................................................................................15 4.2.1 Suitability of Materials ....................................................................................................15 4.2.2 Asphalt Materials ..............................................................................................................15 4.2.3 Stabilization with Hot Asphalt .......................................................................................15 4.2.4 Stabilization with Cutbacks ...............................................................................................17 4.2.5 Stabilization with Asphalt Emulsion ..................................................................................17 4.2.5.1 Classes and Types of Emulsion ........................................................................................ 17 4.2.5.2 Conditions of Mixing ....................................................................................................... 18 4.2.6 Additives............................................................................................................................18 4.2.7 Water Quality ....................................................................................................................19 4.3 Mix Design .................................................................................................................................19 4.3.1 General ..............................................................................................................................19 4.3.1.1 Classifying Material ......................................................................................................... 19 4.3.1.2 Determining Laboratory Optimum Fluid Content and Compacted Density ................... 19 4.3.1.3 Determining Target Residual Asphalt Content ............................................................... 20 4.3.2 Testing and Design Criteria ...............................................................................................22 4.4 Construction Factors Effecting Design Considerations .............................................................22 4.5 Expected Performance and Costs .............................................................................................23 4.6 References ................................................................................................................................23 5.0 CEMENT STABILIZATION ............................................................................................................24 5.1 General .....................................................................................................................................24 5.2 Materials ...................................................................................................................................24 5.2.1 Types of Cement ...............................................................................................................24 5.2.2 Soil-Cement Reactions .....................................................................................................24 5.2.3 Soils Suitable for Cement Stabilization .............................................................................24 5.3 Design Considerations ...............................................................................................................25 5.3.1 Mix Design .........................................................................................................................25 5.3.2 Structural Design ...............................................................................................................25 Soil Stabilization Design Guide v 5.3.2.1 Strength Values ............................................................................................................... 25 5.3.2.2 Stress-Strain Relationship ............................................................................................... 25 5.3.2.3 Fatigue Characteristics .................................................................................................... 27 5.4 Construction ..............................................................................................................................27 5.5 Expected Performance and Costs .............................................................................................28 5.6 References ................................................................................................................................28 6.0 LIME AND LIME/FLY ASH STABILIZATION ..................................................................................29 6.1 General ......................................................................................................................................29 6.2 Materials ...................................................................................................................................29 6.2.1 Types of Lime ....................................................................................................................29 6.2.2 Reactions ...........................................................................................................................30 6.2.3 Properties of Clays Stabilized with Lime ...........................................................................30 6.2.3.1 Rate of Strength Gain ...................................................................................................... 31 6.2.3.2 Moisture-Density Relationships ...................................................................................... 31 6.3 Design Considerations ...............................................................................................................31 6.3.1 Appropriate Conditions for Stabilization with Lime ..........................................................31 6.3.1.1 Material Factors .............................................................................................................. 33 6.3.1.2 Production Factors .......................................................................................................... 33 6.3.1.3 Compaction Process ........................................................................................................ 33 6.3.2 Evaluation and Use of Materials Stabilized with Lime ......................................................34 6.3.3 Choice of Lime Type ..........................................................................................................34 6.4 Construction Considerations .....................................................................................................35 6.5 Expected Performance and Cost ...............................................................................................35 6.6 References ................................................................................................................................35 7.0 MECHANICAL STABILIZATION ...................................................................................................36 7.1 Mechanical Stabilization with Granular Material .....................................................................36 7.1.1 General ..............................................................................................................................36 7.1.2 Materials ...........................................................................................................................36 7.1.3 Design Criteria for Granular Stabilization .........................................................................36 7.1.3.1 Particle-Size Distribution ................................................................................................. 36 7.1.3.2 Plastic Properties ............................................................................................................ 37 7.1.3.3 Strength Tests ................................................................................................................. 37 vi Soil Stabilization Design Guide 7.1.4 Construction ......................................................................................................................37 7.1.5 Expected Life and Performance ........................................................................................38 7.1.6 References ........................................................................................................................38 7.2 Mechanical Stabilization with Geofibers ..................................................................................38 7.2.1 General ..............................................................................................................................38 7.2.2 Materials ...........................................................................................................................39 7.2.3 Design Criteria for Geofiber Stabilization .........................................................................39 7.2.4 Laboratory Strength Tests .................................................................................................41 7.2.5 Construction ......................................................................................................................41 7.2.6 References ........................................................................................................................42 8.0 SALT STABILIZATION ..................................................................................................................43 8.1 General ......................................................................................................................................43 8.2 Materials ...................................................................................................................................43 8.3 Design Considerations ...............................................................................................................43 8.4 Construction Considerations .....................................................................................................43 8.5 Expected Performance and Costs .............................................................................................43 8.6 References ................................................................................................................................43 9.0 Non-Traditional Stabilization ....................................................................................................44 9.1 General ......................................................................................................................................44 9.2 Dust Suppression ......................................................................................................................44 9.2.1 Good Construction and Maintenance Techniques ...........................................................44 9.2.2 Mechanical Stabilization ...................................................................................................44 9.2.3 Chemical Binders ...............................................................................................................44 9.2.3.1 Organic Non-asphalt Products ........................................................................................ 45 9.2.3.2 Water-Attracting Chemicals ............................................................................................ 45 9.2.3.3 Petroleum-Based Products ............................................................................................. 45 9.2.3.4 Electrochemical Stabilizers ............................................................................................. 45 9.2.3.5 Polymer Stabilizers .......................................................................................................... 45 9.3 Expected Performance ..............................................................................................................46 9.3.1 Improvement of Fairbanks Silt with Polymer Emulsion Stabilizers and Geofibers ...........48 9.3.2 Improvement of Western Alaska and with Polymer Emulsion Stabilizers and Geofibers ...................................................................................................................................48 Soil Stabilization Design Guide vii 9.4 Construction Considerations .....................................................................................................50 9.4.1 Specific Concerns When Using Geofibers with Polymer Stabilizers .................................50 9.5 References ................................................................................................................................52 10.0 OTHER STABILIZING TECHNIQUES .............................................................................................53 10.1 General ......................................................................................................................................53 10.2 Drainage ....................................................................................................................................53 10.3 Geotechnical Fabrics .................................................................................................................53 10.4 Expected Life and Costs ............................................................................................................53 10.5 References ................................................................................................................................54 APPENDIX A: Glossary of Terms ................................................................................................................55 APPENDIX B: Reference List on Stabilization—Alaska DOT&PF ................................................................58 APPENDIX C: Soils of Alaska ......................................................................................................................60 viii Soil Stabilization Design Guide