Laydown & Compaction

The California Asphalt Pavement Association

October 25-26, 20172017 Fall Conference; Doubletree Hotel, Sacramento , CA

Promoting

Learning

Advocating

Networking

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2013 Utah Asphalt Conference; Sandy UT - March 27-28, 2013

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We are ENGINEERS

HOW do we make it happen!!!

2013 Utah Asphalt Conference; Sandy UT - March 27-28, 2013

2013 Utah Asphalt Conference; Sandy UT - March 27-28, 2013

What is Compaction? Performance Requires Proper Compaction Keys to Compaction Quality Control Summary

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“to join or pack closelytogether; consolidate;condense.”

– dictionary.com

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1% change of in-place density = 10% change in performance life!!!

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Mix Characteristics

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Nominal maximum size: “one sieve size larger than the first sieve to retain more than 10 percent of the material” - NAPA

t/NMAS

3:1 minimum

4:1 optimal

5:1 very coarse mixes

6:1 adjust thickness or mix type

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Data: NCAT

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NCAT - Brown and Heitzman 2013

Permeability in a coarse dense-graded 12.5mm Superpave surface mix

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What happens when mix voids change?

Higher?

Lower?

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Temperatures

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Compact at the highest temperature possible!!

What is that Temperature?

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Does the mix have tender zones?

What temperature range should we avoid compactive effort?

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3 Inch Lift50°F Air &

Surface Temp300°F Mix

Delivery temp44 min to

complete compaction operations

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1” - Lift

50°F - Air &

Surface Temp

300°F - Mix

Delivery temp

7 minutes to

complete

compaction

operations

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Existing Pavement Structure

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If there is surface cracking or rutting due to plastic movement of the mix, the entire surface should be milled

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Laydown Process

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Rolling Operations

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What drum width is right for the project?

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Key considerations for optimizing roller operations: Frequency Amplitude Speed Passes

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Wid

th o

f m

at Pass1

Pass 2

Pass 3

Pass 4

This is a 5 pass pattern that

provides 2 complete coverages.

Conduct trial section to determine appropriate equipment setup and rolling pattern to achieve target densities.

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MIX PROD SCREED BREAK INTER FINISH

Trial 1 325F 290F 280F 250F 200F

Trial 2 290F 250F 240F 190F 135F

MIX AVG (%) BREAK INTER FINISH

Trial 1 93.2 4V 4V 2V

Trial 2 94.1 2V 4V 2S

Temperature

Density

Contractor QC Inspection

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Monitor Operations:

Temps

Density

Rolling pattern

Mix properties

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Intelligent Compaction (IC)

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“Intelligent compaction (IC) is an innovative pavement construction technology that equips conventional rollers with instrumentation that is used to monitor and control the material compaction process.”

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“…ensures that the target properties of the layer are more uniform and are more efficiently achieved.”

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GPS Positioning

Passes

Location

Temperature ICMV Real-Time Graphical

Interface Data Analysis

“…ensures that the target properties of the layer are more uniform and are more efficiently achieved.”

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“…ensures that the target properties of the layer are more uniform and are more efficiently achieved.”

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1. The primary conclusion that can be drawn from the FHWA/TPR study is that IC is very effective for achieving the target level of HMA compaction while at the same time increasing the uniformity of the material.

2. The IC roller demonstrations provided proof that IC rollers could track roller passes, monitor HMA surface temperature, and report an ICMV that the operator could use to better control the compaction process.

5. IC equipment can be used effectively to develop compaction curves and to determine the optimum number of roller passes.

6. The correlation studies show correlation between the ICMVs and in-situ measurements, including HMA density (from nuclear and non-nuclear density gauges) and certain deflection-based parameters i.e., normalized maximum deflection and layer modulus. However, there is considerable variability in the correlations.

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Rolling Towards Performance

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Establish the targets Identify the equipment

setup, the pattern, and the monitoring schedule.

Identify control and action limits

Identify actions to reestablish target

What contributes to success? Mix quality Temperatures

(ambient & mix Existing structure Equipment setup Rolling Pattern

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COMMUNICATION UNIFORMITY

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Brandon Milar, P.E.Technical DirectorCalifornia Asphalt Pavement Association916-995-0086bmilar@calapa.netwww.calapa.net

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