PowerPoint Presentation Template 1,...

307-213-0223 [email protected] ©Mike Robinson, PE

In-Situ Recycling

• Reduced material buy

• Reduced haul cost

• Reduced haul damage

• Reduced traffic congestion

• Reduced project duration

• More value


CIR-EAM

• Treats all existing pavement distresses

• Flexible – avoids rigid or semi-rigid

behavior

• Treated material approaches plantmix

strength


Caltrans vs Local Agencies

• Different Needs and Goals

• Different Approaches

• Different Staffing

• Different Budgeting

• Different Accountability

• Different Appetite / Need for Risk


Section Design

• Caltrans method doesn’t recognize the

true properties of CIR-EAM Interim Report on I-80 in Placer County – 2006

“Conservative approach” estimated Gf of 1.4, even though

worst-case prediction from actual material testing resulted

in Gf of 1.8

UCPRC Guidelines – 2009: Gf of 1.4

Caltrans Maintenance FDR Using Foamed Asphalt –

2012: Gf of 1.4

Less than a 30% improvement over AB


Recent research – AASHTO ‘93 Structural

Coefficients

• Foamed Asphalt report at the Mid-Continent

Transportation Research Symposium 2003 –0.18 –

50% improvement over AB

• Kowalski & Starry, 2007 – 0.13 to 0.36

• Wirtgen Cold Recycling Manual, 2012 – up to 0.35

• Maryland SHA, 2013 – 0.30 to 0.35

• Khosravifar, Schwartz, and Goulias, 2015 –

International Journal of Pavement Engineering – 0.36

Three times stronger than AB and approaching HMA


AASHTO ‘93

• World-wide use

• Based on full-

scale testing

• Supporting

research on-

going


AASHTO ‘93

• More focused

look at traffic

• No arbitrary SG

strength

limitation

• Material

variability

• Overall reliability


Updated AC and CIR-EAM Strengths


“Equivalent” Designs

R-value 70 – 121,000 ESALs – TI of 7.0

AASHTO ‘93 Caltrans

Chip Seal over 3.5” CIR-EAM

2” HMA over 6.5” CIR-EAM


R-value 70 – 5,400,000 ESALs – TI of 11.0

AASHTO ‘93 Caltrans

2” HMA over 3.5” CIR-EAM

6”

HM

A o

ver

8”

CIR

-EA

M


You can still use the Caltrans Method

• Stick with their VERY conservative value

• Use a higher value based on some

interpolation

It basically all comes down to risk.


Changes


“Throw a couple of bags of cold mix in that

pothole…”

Photo courtesy of Dustin Hamilton


Mike Robinson LLC

101 Upper Canyon Loop

Ten Sleep, WY 82442

(307) 213-0223 [email protected]

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