Transcript Document

Using CFB Ash As A Substitute For Portland
Cement In Full Depth Reclamation
Prepared For
ARIPPA
TECHNICAL
SYMPOSIUM
Presented By
Steve Dixon, Civil & Environmental Consultants, Inc.
Jim Panaro, Robindale Energy Services, Inc.
August 20, 2014
Items To Be Covered
► A Description Of The Full Depth Reclamation Process
► Why Is It Needed?
► The Benefits Of Full Depth Reclamation
► State DOTs Involved With Full Depth Reclamation
► A Closer Look At PennDOT And Full Depth Reclamation
► Full Depth Reclamation Test Project Using CFB Ash In
Butler County, PA
Full Depth Reclamation (FDR) - Introduction
► Full depth reclamation is a rehabilitation technique in
which all of the asphalt pavement section and a
predetermined amount of underlying materials are treated
to produce a stabilized base course.
FDR - Introduction
► The Procedure Consists Of Five Steps:
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Pulverization Of Existing Materials
Stabilization - Introduction Of Additive(s)
Shaping Of The Mixed Material
Compaction
Application Of Driving Surface
FDR - Introduction
► The Procedure Consists Of Five Steps:
▪ Pulverization Of Existing Materials
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Stabilization - Introduction Of Additive(s)
Shaping Of The Mixed Material
Compaction
Application Of Driving Surface
Pulverization - Reclaiming Machine
Pulverization & Mixing
► Pulverization consists of grinding the road surface and
base to be reclaimed
Close-Up Of Milling Drum
FDR - Introduction
► The Procedure Consists Of Five Steps:
▪ Pulverization Of Existing Materials
▪ Stabilization - Introduction Of Additive(s)
▪ Shaping Of The Mixed Material
▪ Compaction
▪ Application Of Driving Surface
Stabilization
► Mechanical Stabilization – Addition Of Aggregate Material
► Bituminous Stabilization – Addition Of Asphalt-Based
Emulsions
► Chemical Stabilization –
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Lime
Cement
Fly Ash
Combination
FDR - Introduction
► The Procedure Consists Of Five Steps:
▪ Pulverization Of Existing Materials
▪ Stabilization - Introduction Of Additive(s)
▪ Shaping Of The Mixed Material
▪ Compaction
▪ Application Of Driving Surface
FDR - Introduction
► The Procedure Consists Of Five Steps:
▪ Pulverization Of Existing Materials
▪ Stabilization - Introduction Of Additive(s)
▪ Shaping Of The Mixed Material
▪ Compaction
▪ Application Of Driving Surface
FDR - Introduction
► The Procedure Consists Of Five Steps:
▪
▪
▪
▪
Pulverization Of Existing Materials
Stabilization - Introduction Of Additive(s)
Shaping Of The Mixed Material
Compaction
▪ Application Of Driving Surface
Location Of Shale Formations
Source: Marcellus Sale Coalition
Stress On Secondary Roads
FDR - Benefits
(Graphic by cement.org)
States Having Significant Experience With FDR
► California
► Georgia
► Illinois
► Iowa*
► Kansas*
► Maine
► Michigan
► Missouri*
► New Mexico
► Ohio*
► Oregon
► Pennsylvania*
► Texas
► Virginia
► Washington
PennDOT Publications That Have Been Updated To
Include FDR
► Publication 408 – Highway Specifications
► Publication 242 – Pavement Policy Manual
► Publication 27 - Bituminous Concrete Mixtures, Design
Procedures, And Specifications For Special Bituminous
Mixtures
► Publication 23 – Maintenance Manual (FDR as a
maintenance strategy)
► Publication 30 – Portland Cement Concrete (Mix Design
Procedure for Chemical Stabilization as a Full Depth
Reclamation Method).
PennDOT Publication 30: Mix Design Procedure For Chemical
Stabilization As A Full Depth Reclamation (FDR) Method
► “Stabilizing Agent Can Be The Following Materials Or
Combination Of These Materials:
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Cement: Publication 408, Section 701 (3 to 8% by weight)
Hydrated Lime: Publication 408, Section 723 (2 to 6% by weight)
Fly Ash: Publication 408, Section 724.2(a) (6 to 14% by weight)
Lime Pozzolan: Publication 408, Section 725 (6 to 8% by weight)
Quicklime
Class C Fly Ash
Fluidized Bed Combustion Fly Ash”
PennDOT Publication 30: Mix Design Procedure For Chemical
Stabilization As A Full Depth Reclamation (FDR) Method, Continued
► “Fluidized Bed Combustion Fly Ash Has Been Used As A
Partial Cement Replacement With Success.”
► “For The Final Mix Design, The Required Amount Of
Cement Will Be That Which Provides An Average
Unconfined Compressive Strength Of The Three
Specimens Not Less Than 2068 kPA (300 psi) In 7 days.
Hydrated Lime or Fly Ash (Including Fluidized Bed
Combustion Fly Ash) Can Be Used In Place Of Cement As
Long As The Desired Strength Can Be Met.”
PennDOT FDR Report
Elements Of An FDR Project
Source: PennDOT Pub 23
PennDOT FDR Test Projects
► SR 1017 Dauphin County
▪ Chemical Stabilization Agent: Asphalt Emulsion
▪ Project Duration: 8/23/2010 – 8/26/2010
▪ Length Of Test Section: 0.7 Miles
► SR 3016 Butler County
▪ Chemical Stabilization Agents: Portland Cement And Portland
Cement/CFB Fly Ash
▪ Project Duration: 6/11/2011 – 6/14/2011
▪ Lengths Of Test Sections: Multiple
PennDOT FDR Test Project – SR 3016 Butler County, PA
PennDOT FDR – Test Sections
► June 6, 2011:Total Length Of Road = 927 Feet
▪ Sections 1 & 2 - Cement As The Stabilizing Agent.
Application Rate Was 7.27 lbs/ft2
▪ Sections 3 & 4 – Combination Fly Ash And Cement.
Application Rate Was 6.18 lbs/ft2, 4.32 lbs/ft2 For Fly Ash
(Target Was 3.61 lbs/ft2)
► June 7, 2011: Total Length of Road = 900 feet
▪ Entire Section - Combination Of Fly Ash and Cement Placed
In Layers, First Fly Ash And Then Cement. Application Rate
Was 7.10 lbs/ft2 (4.95 lbs/ft2 For Fly Ash)
▪ Thickness Of Fly Ash Ranged From 1.00 Inch To 1.60 Inches
While The Combination Of Fly Ash & Cement Ranged From
1.75 Inches To 2.38 Inches
PennDOT FDR – Test Sections, continued
► June 8, 2011: Total Length of Road = 900 Feet
► Three, 300-foot Sections Using A Fly Ash And Cement
Mixture
► Application Rate Was 4.75 lbs/ft2 For Fly Ash And 5.68
lbs/ft2 For The Fly Ash And Cement Combination
Stabilization
► CFB Ash And Portland Cement, About To Be Applied
(Previously Compacted Surface In The Foreground)
Challenges With Placing Dry Stabilizing Agents
Second Pass Of The Reclaimer
► Stabilizing Agents, CFB Ash And Cement, And Water Are
Integrated Into The Pulverized Roadway
Mixing
► Mixture Of Water, CFB Ash, And Portland Cement Exiting
Rear Of Reclaimer
Mixing
Second Pass Mixing
CFB Stabilizing
Agent
Shaping
► Grading To Achieve Desired Surface Profile
Shaping, continued
Shaping, continued
Compaction
► Methodology Should Be Matched To The Depth Of The
Reclamation. To Achieve The Maximum Benefits From
This Process The Base Needs To Be At Maximum Density
Quality Assurance & Acceptance
► At Least 95% Compaction At Optimum Moisture
► Optimum Moisture Can’t Be Exceeded By More Than 3%
► Cores Were Taken From The Section After A Seven Day
Wet Cure Period. The Performance Was Within The
Acceptable Target Range Of 200-500 psi.
► Hot Mix Asphalt Overlay Was Placed As The Final Wearing
Surface
Compacted Road Awaiting Performance Testing
Sections Of FDR Test Road
6/7/2011
7/3/2014
Sections Of FDR Test Road
6/7/2011
7/3/2014
Sections Of FDR Test Road
7/3/2014
7/3/2014
Happy Motoring!