1. Full Depth Reclamation Current Practice Testing Variability Presented To: Canadian User Group for Asphalt Sunday, November 15, 2009 Delta Beausejour Hotel Moncton, New Brunswick Tom Dziedziejko AME Materials Engineering

2. FDR Rehabilitation Technique that processes the full depth of asphalt pavement and a predetermined portion of the underlying base materials Rehabilitation Technique that processes the full depth of asphalt pavement and a predetermined portion of the underlying base materials Uniformly pulverizes and blends to provide an upgraded and homogeneous material Uniformly pulverizes and blends to provide an upgraded and homogeneous material

3. FDR Equipment Including some underlying granular helps cool cutting tools and enhances pulverization action Including some underlying granular helps cool cutting tools and enhances pulverization action Allows simultaneous injection of stabilizing agents. Allows simultaneous injection of stabilizing agents. Pulverizing drum rotates in an up-cut direction or opposite to the forward direction of travel. Pulverizing drum rotates in an up-cut direction or opposite to the forward direction of travel.

4. FDR Equipment Screen Deck CrusherBelt Scale Pug-Mill and Expansion Manifold Paver Laid FDR Recycling Trains Pulverize, Wind row, Pick up

5. Distresses That Can Be Treated Cracking Cracking Age, Fatigue, edge, slippage, block, longitudinal, reflection, continuity Age, Fatigue, edge, slippage, block, longitudinal, reflection, continuity Ride Quality Ride Quality Bumps, Localized Depressions, Cross fall correction, Bumps, Localized Depressions, Cross fall correction, Permanent Deformation Permanent Deformation Rutting, Shoving, Wash Boarding Rutting, Shoving, Wash Boarding General Deterioration General Deterioration Raveling, Potholes, Stripping, Delamination, etc. Raveling, Potholes, Stripping, Delamination, etc. Inadequate Structural Capacity Inadequate Structural Capacity

6. Candidates for FDR Good Candidate Good Candidate Good But Approach with Caution Good But Approach with Caution Potential serious underlying problems Potential serious underlying problems Enhancement likely required Enhancement likely required

7. Candidates for FDR If existing pavement structure is adequate for loads then simple pulverization and regrading may be all that is required before applying surface. If existing pavement structure is adequate for loads then simple pulverization and regrading may be all that is required before applying surface. Corrective aggregate may be required to ensure adequate drainage and mechanical properties of the treated material. Corrective aggregate may be required to ensure adequate drainage and mechanical properties of the treated material. If structural enhancement is required then stabilizing agents can be added If structural enhancement is required then stabilizing agents can be added Type of agent used should be selected based on the properties of the material present. Type of agent used should be selected based on the properties of the material present.

8. Types of Stabilizing Additives Bituminous Bituminous Foamed Asphalt Foamed Asphalt Asphalt Emulsions Asphalt Emulsions Chemical Chemical Portland Cement Portland Cement Lime Lime Fly Ash Types C and F Fly Ash Types C and F Kiln Dust (Lime/LKD or Cement/CKD), Cement, Lime Blends Kiln Dust (Lime/LKD or Cement/CKD), Cement, Lime Blends Combinations of the above Combinations of the above Bituminous additives blended with Chemical additives Bituminous additives blended with Chemical additives

9. Types of Stabilizing Additives Popularity of Recycling is spawning interest in new stabilizers and additives Popularity of Recycling is spawning interest in new stabilizers and additives Foam Enhancing additives Foam Enhancing additives Pine Tar Emulsions Pine Tar Emulsions

10. Bituminous Additives Asphalt Emulsions Asphalt Emulsions Coats all aggregates with emulsion Coats all aggregates with emulsion Emulsion breaks leaving particles cemented together with bitumen Emulsion breaks leaving particles cemented together with bitumen Paving can not proceed until emulsion break is complete Paving can not proceed until emulsion break is complete Days? Weeks? Cement sometimes added to accelerate break of emulsion Days? Weeks? Cement sometimes added to accelerate break of emulsion

11. Bituminous Additives Foamed Asphalt Foamed Asphalt Fast becoming the most popular choice for FDR Fast becoming the most popular choice for FDR Small amount of water added to hot asphalt results in foam Small amount of water added to hot asphalt results in foam Pulverized material needs fines present up to 20% Pulverized material needs fines present up to 20% Foam mixes with fines present in material to form a mastic binder Foam mixes with fines present in material to form a mastic binder Mastic spot welds to larger aggregate in material to form bonds that hold mix together Mastic spot welds to larger aggregate in material to form bonds that hold mix together Aggregates with PI as high as 15 treated successfully with no special processes Aggregates with PI as high as 15 treated successfully with no special processes Typical delay before paving - two days Typical delay before paving - two days

12. Additive Selection for FDR FDR is a Soil Stabilization Technique FDR is a Soil Stabilization Technique When Bituminous Additives are used the process becomes a Hybrid Asphalt and Soil product When Bituminous Additives are used the process becomes a Hybrid Asphalt and Soil product Asphalt products provide a binder system Asphalt products provide a binder system Produces a flexible material with properties that resist fatigue and adds flexibility to the processed mat. Produces a flexible material with properties that resist fatigue and adds flexibility to the processed mat. Additives used provide some enhancement to asphalt interaction with soils but also impacts soil properties similar to soil stabilization techniques. Additives used provide some enhancement to asphalt interaction with soils but also impacts soil properties similar to soil stabilization techniques.

13. Chemical Additives Lime Lime Most often used where soil has high PI (>10) Most often used where soil has high PI (>10) Benefits Benefits Mitigates effect of reactive clays Mitigates effect of reactive clays Reduces PI of soil after application and reduces swelling potential Reduces PI of soil after application and reduces swelling potential Decreases susceptibility to moisture damage (stripping) Decreases susceptibility to moisture damage (stripping) Increases tensile and compressive strength of mix Increases tensile and compressive strength of mix Typical addition 1% to 3% Typical addition 1% to 3% No Lime2%Hydrated Lime Dry Strength 445 kPa372 kPa Wet Strength 128 kPa223 kPa TSR 29%60%

14. Chemical Additives Portland Cement Portland Cement Most often used where soil has low PI (<10) Most often used where soil has low PI (<10) Primarily adds strength to weak materials Primarily adds strength to weak materials Benefits Benefits Increases compressive strength of mix. Increases compressive strength of mix. Strength increase over time Strength increase over time Impact on moisture susceptibility variable (stripping) Impact on moisture susceptibility variable (stripping) Typical addition 1% to 2% Typical addition 1% to 2% Excessive addition results in potential cracking of the stabilized soil Excessive addition results in potential cracking of the stabilized soil No Portland Cement With 2% Portland Cement Dry Strength 276 kPa341 kPa Wet Strength 163 kPa216 kPa TSR 59%63%

15. Chemical Additives Fly ash Fly ash Fly ash is a pozzolan typically requiring presence of lime or hydrating cement to gain strength Fly ash is a pozzolan typically requiring presence of lime or hydrating cement to gain strength Some clays can react with calcium oxide in Type C Fly ash alone resulting in strength gain. Some clays can react with calcium oxide in Type C Fly ash alone resulting in strength gain. Some fly ash has percentage of lime present that allows some hydration Some fly ash has percentage of lime present that allows some hydration Potential to Mitigate effect of reactive clays - Lime Potential to Mitigate effect of reactive clays - Lime Slower strength gain than cement but carries on longer Slower strength gain than cement but carries on longer Excessive addition results in potential cracking of stabilized soil Excessive addition results in potential cracking of stabilized soil No Fly AshWith 1% Fly Ash Dry Strength 260 kPa271 kPa Wet Strength 168 kPa292 kPa TSR 65%108% Data Source: Job Report Cold Recycling WR 2500: Foam recycling in Estes National Park, Colorado /USA

16. Pre Engineering Rule of Thumb Engineering is the Most Costly Form of Design Rule of Thumb Engineering is the Most Costly Form of Design Proper Engineering Assessment should be carried out to identify the best choice of additive. Proper Engineering Assessment should be carried out to identify the best choice of additive. Must consider : Must consider : Amount of strength enhancement required. Amount of strength enhancement required. Pavement Structural Design – Traffic? Pavement Structural Design – Traffic? Type and quality of base materials present Type and quality of base materials present Drainage Characteristics Drainage Characteristics Presence of Clays and Silts Presence of Clays and Silts Plasticity Index Plasticity Index Pavement Drainage Pavement Drainage Ditching Ditching Sub drains Sub drains

17. Pre Engineering Thickness of existing pavement Thickness of existing pavement Optimize percent of pulverized pavement in process depth Optimize percent of pulverized pavement in process depth + 60% RAP + 60% RAP Identify excessively thick areas Identify excessively thick areas Over 200mm pavement depth could be a problem to process due to equipment capacity Over 200mm pavement depth could be a problem to process due to equipment capacity Consider Pre-milling Options to reuse excess in other parts of project. – Shoulder stabilization Consider Pre-milling Options to reuse excess in other parts of project. – Shoulder stabilization

18. Pre Engineering Proper Mixture Design Proper Mixture Design Pre tender laboratory design trials to confirm additive selected will work is advisable. Pre tender laboratory design trials to confirm additive selected will work is advisable. Mix design before construction is compulsory Mix design before construction is compulsory

19. Testing Variability Internal = 26 o C Surface = 24 o C Internal = 34 o C Surface = 28 o C Accurate Test Results Dictate Acceptance Stabilized Sample Temperature is Critical Temp = 25 C: Strength = 360 Temp = 26 C: Strength = 340

20. Test Variability Strength Change with Varying Conditioning Temperature Strength Change with Varying Conditioning Temperature

21. Testing Variability 2 Hrs Room Curing 4 Hrs Room Curing 24 Hrs Room Curing

22. Testing Variability Optimum Moisture – Field Sample – AC 2.8% Strength Varies with moisture content at time of compaction

23. Conclusions Select FDR based on engineering design Select FDR based on engineering design Selected process and enhancement should be based on existing conditions. Selected process and enhancement should be based on existing conditions. Chemical treatments should be established using Material requirements Chemical treatments should be established using Material requirements Ensure Quality Verification Testing is completed accurately Ensure Quality Verification Testing is completed accurately Sample Temperature significantly influences results Sample Temperature significantly influences results

24. Thank You Questions ?