full-depth reclamation pavement rehabilitation method existing asphalt, cabc and a pre-determined...

Full-Depth Reclamation

Pavement Rehabilitation Method • existing asphalt, CABC and a pre-determined

depth of the subgrade soils are uniformly pulverized and blended

• Chemical additive (cement) and water are added, material is mixed and compacted

• “Reclaimed” material acts as a new base material for the placement of a new asphalt course

Full-Depth Reclamation

• Referenced by NCDOT Section 541

• Flexible Pavement Reclamation Using Portland Cement - on NCDOT Geotechnical Engineering Unit website

• www.ncdot.org/doh/preconstruct/highway/ geotech/supportserv/geopavement/• Then choose “FDRwithcement.pdf”

Full-Depth Reclamation

Recently Performed for 2 S&ME Projects

• Trinity Industrial Park Roadways (documented with photos herein)

• Forsyth Technical Community College Greene Hall Parking Lot

Trinity Industrial Park Roadway Prior to Improvement –

Subjected to Relatively Heavy Truck Traffic Volume

Full-Depth Reclamation

• Asphalt pavement had moderate to severe distress with cracking, potholes, and rutting

• 14 cores encountered 1.25“ to 3.25“ asphalt and 2.25” to 9.75” of aggregate base course

• Borings encountered variably compacted, high plasticity clay fill to depths of 2 to 4.5 feet

Trinity Industrial Park Roadway Prior to Improvement –

Subjected to Relatively Heavy Truck Traffic Volume

Full-Depth ReclamationTrinity Industrial Park Roadways

• Obtained bulk sample of asphalt, base course, soils and performed LABORATORY MIX DESIGN

• Mix design for cement contents of 3%, 6% and 9% by weight

• Performed standard Proctor test for each cement content

• Compressive strength specimen were molded at each cement content – compressive strength testing performed

• A target compressive strength between 300 and 400 psi is recommended by research and industry literature for the reclaimed materials

• Laboratory test results indicated a compressive strength of 350 psi for approx. 6.5% cement by weight

Full-Depth Reclamation

Trinity Industrial Park Roadways

• New pavement section – 4 inches asphalt / 12 inches of reclaimed material was recommended as option to conventional remove/replace

• Full-Depth Reclamation was bid as well as conventional remove/replace pavement construction

• Full-Depth Reclamation was lowest cost

Trinity Industrial Park Roadways

Cement placed on existing asphalt

Trinity Industrial Park Roadways

Materials Pulverized & Mixed - 12 inches deep

Trinity Industrial Park Roadways

After Dry Mixing

Trinity Industrial Park Roadways

Adding Water & Mixing Again

Trinity Industrial Park Roadways

Adding Water & Mixing Again

Trinity Industrial Park Roadways

• Reclaimed material was compacted and then proofrolled prior to placement of new asphalt

• Reclaimed material was stable during proofroll evaluation

• No undercutting was necessary prior to, during, or after FDR was performed

Trinity Industrial Park Roadways

Trinity Industrial Park Roadways