Full-Depth Reclamation Using a Cement Slurry Spreader Attached to a Ready Mixed Concrete Truck W. Spencer Guthrie, Ph.D., Associate Professor Charles A.

Full-Depth ReclamationUsing a Cement Slurry Spreader Attached to aReady Mixed Concrete Truck

W. Spencer Guthrie, Ph.D., Associate ProfessorCharles A. Hope, EIT, Graduate Research Assistant

Department of Civil and Environmental Engineering, Brigham Young University

ASCE Infrastructure Report Card

Water Content

Cem

ent

Co

nte

nt

Cast

Rolled

No Wearing Course RequiredWearing Course Required

Roller-Compacted Concrete

Conventional Concrete

Soil-Cement

Flowable Fill

Cement-Modified Soil

Full-DepthReclamation

Cement-Treated Base

Cement-Based Pavement Materials

PerviousConcrete

Definition ofFull-Depth Reclamation (FDR)

“…technique in which the full flexible pavement section and a

predetermined portion of the underlying materials are uniformly crushed, pulverized, or blended,

resulting in a stabilized base course; further stabilization may be obtained through the use of

available additives.” - Asphalt Recycling and Reclaiming Association

FDR is most appropriate under the following conditions:

■ The pavement is seriously damaged and cannot be rehabilitated with simple resurfacing.

■ The existing pavement distress indicates that the problem likely exists in the base or subgrade.

■ The existing pavement distress requires full-depth patching over more than 15 to 20 percent of the surface area.

■ The pavement structure is inadequate for the current or future traffic.

• Uses in-place materials• Requires little or no

material to be hauled off• Maintains or improves

existing grade• Conserves virgin material• Saves cost by using

in-place “investment”• Saves energy by reducing

mining and hauls• Is a very sustainable

process

Advantages of the FDR Process

Benefits of FDR Using Cement

• Increased rigidityfor distributing loads• Elimination of rutting below surface• Reduced moisture and frost susceptibility• Reduced fatigue cracking• Thinner pavement sections

Rehabilitation Strategies

Attribute

Rehabilitation Strategy

Reclamation with Cement

Structural Overlay

Removal and Replacement

New pavement structure

Fast construction X

Minimal traffic disruption X X

Minimal material in/out X X

Conservation of resources X XMaintenance of existing elevation X

Low cost X X

Pulverize, Shape, Add Cement, Mix In Place, Compact, and Surface

GranularBase

Subgrade

Existingroad

Bituminous Surfacing

Subgrade

Pulverized

Pulverizationto desired

depth

Subgrade

Pulverized

Removal ofexcess

material (if necessary)and shaping

Subgrade

Stabilized

Addition of cement, mixing,

reshaping, and compacting

Subgrade

Stabilized

New Surfacing

Application of final surface

course

FDR Construction Process

Pulverization

Reshaping

Cement Spreading

Cement Spreading

Cement Uniformity

Material Blending

Compaction

Grading

Curing

Minimal Disruption

Microcracking

Microcracking

Surfacing

• Service Life = 20 years• Design Equivalent Single Axle Loads =

15,000• Overall Standard Deviation = 0.45• Initial Serviceability = 4.5• Terminal Serviceability = 2.0• Asphalt Structural Layer Coefficient =

0.40• Cement-Treated Base Structural Layer

Coefficient = 0.18• Drainage Coefficient = 1.0• Subgrade Resilient Modulus = 15 ksi

New Surfacing

Subgrade

8 in. CTB

3 in. HMA

Final Pavement Structure

Pavement Analysis

Cost = 20% Less than Traditional Reconstruction

Reliability = 99.99%

Summary

• FDR with cement stabilization provides a durable structural layer with many engineering, environmental, and economic benefits

• Cement can be applied on urban projects with a slurry spreader attachment to ensure uniformity and eliminate all fugitive dust

Thank You!

guthrie@byu.edu charleshope@byu.net