Name Says It All

Standard PracticeTo Develop a

Quality Control/Quality Assurance Plan for HMA

Significance

• Quality Control Plan for Contractor• Quality Assurance Plan for SHA

LABORATORIES

• AMRL Proficiency and Inspection• OR

• State Sponsored Program• Plus

• Qualified Personnel (Contractor and SHA)

STATE HIGHWAY AGENCY RESPONSIBILITIES

• Review Contractor Design• Review Contractor Quality Control

Program• Quality Assurance Testing

CONTRACTOR RESPONSIBILITIES

• Perform Designs

• Develop QC Plan

• Execute QC Plan

MIX DESIGN FORMULA ADJUSTMENT

• First Lot to Dial Mixture In• Amount of Adjustment Allowed

Mix Composition Property AdjustmentLimit

Asphalt Binder Content (Pb) +/- 0.4

Gradation Passing 4.75 mm

and Larger Sieves

+/- 4.0

Gradation minus 2.36 mm to

0.150 mm Sieve

+/- 4.0

Gradation minus 0.075 mm Sieve +/- 1.5

Voids Mineral Aggregate (VMA) +/- 1.0

Voids Filled with Asphalt (VFA) +/- 5.0

MIX DESIGN FORMULA ADJUSTMENT

• Job Mix Formula (JMF) to be declared at end of lot

• JMF must meet MP-2

MIX PRODUCTION STOPPED IF

• Air voids >2.0% from target in one sub-lot• Air voids >1.5% from target in two sub-lots• Percent AC >0.5% from target in sub-lot• Any other property >2 times value in table

in one sub-lot• Any other property > value in table in two

sub-lots

EXAMPLE

• % Air = 4% <2.0%, >6.0% in one<2.5%, >5.5% in two

• %AC = 5.4% <5.0%, >5.8% in one

• % #8 = 31% <23%, >39% in one<27%, >35% in two

• %VMA = 14.6% <12.6%, >16.6% in one<13.6%, >15.6% in two

INITIAL PRODUCTION ACCEPTANCE

• IF OKAccept mix with pay factor 1.00

• IF STOPSHA determine value of mix

PLANT SAMPLES

• Two Methods

• from mat behind paver (random X and Y)• from truck (random ton)

ROAD

• Test Strip500 feet min

• Peak Densitynon-destructive gage

• Core Strip get offset from gage

QUALITY CONTROL SYSTEM

• Minimum Properties – %AC– Gmm– % Air Voids– % VMA– % VFA– Moisture Content– % passing key sieves

PROJECT SPECIFIC

• Personnel• Plant Operations• Transportation• Roadway Operations• Compaction Equipment

QUALITY ASSURANCE

• Mixture Properties Typically– %AC– % Air Voids– % VMA

STATISTICALY BASEDACCEPTANCE

• PWL using Standard Deviation• PWL using Conformal Index• Mean and Range

IN PLACE DENSITY

• 2 cores (or non-destructive test) / sub-lot

SMOOTHNESS

• Use a method

SEGREGATION

• Consider a Method

CONTRACTOR ACCEPTANCE

• Included Independent Verification• SHA have statistical method to compare

APPENDICES

• Random Sampling• Control Charts• Quality Control Requirements• PWL with Standard Deviation• PWL with Conformal Index• Mean and Range• Example Specification