Quality Assurance Where does the Future Lead US John D Angelo D Angelo Consulting, LLC johndangelo@cox.net
Why is Quality Assurance Important? Approximately 50% of construction costs are spent on the PURCHASE of materials.
Quality Assurance Costs are Small However, they Critically Impact the Overall Quality of the Whole Project Project Costs Quality Assurance Costs
Background Acceptance procedures Once material is in place it stays in place Only industry paying for marginally acceptable material
QA Concepts Quality Assurance = Acceptance + Quality Control QA = A + QC 5 China - 2005
Field Management, QC QC, Quality Control is Testing performed by the Contractor to ensure the production process is in control.
Field Management, A A, Acceptance is Testing required by the Specifying Agency to accept the product. Acceptance Testing can be performed by: The Contractor The Specifying Agency, or An Independent Laboratory
What tests can we perform? Aggregate Gradations Beltcuts, Hot Bins, Extracted agg. Gradations Mixture Volumetrics Asphalt binder content (Nuclear, Ignition, Solvent) Gmm (T209-Rice Gravity, Corelok) Gmb (T166, Corelok) Pavement Smoothness Density (Nuclear, Cores)
Field Tests? Aggregate Gradations Beltcuts, Hot Bins, Extracted agg. Gradations Mixture Volumetrics Asphalt binder content (Nuclear, Ignition, Solvent) Gmm (T209-Rice Gravity, Corelok) Gmb (T166, Corelok) Pavement Smoothness Density (Nuclear, Cores)
HOWDO WEDESIGN? DESIGN PERFORMANCE QC PRODUCTION ACEPTANCE
Selection of Materials Mixture Design Selection of the Design Aggregate Structure Selection of the Design Binder Content Evaluation of Moisture Sensitivity Develop LTMF
Mixture Design Va (Voids - % of Gmm @ Ndes VFA (Voids filled w/ Asphalt) VMA (Voids in Mineral Aggregates) F/Pbe (Fines to Effective asphalt content ratio) Develop LTMF China - 2005
DESIGN FOR VOIDS! Va VMA VFA F/Pbe BUILD FOR VOIDS!
Mix Verification
Mix Verification Procedure First Day of Production (Lot 1) 3 to 4 HMA Samples, determine: Gradation & Asphalt Binder Content (P b ) Voids (V a ) & VMA 3 to 4 Pavement Samples, determine: In-place Density Smoothness
AASHTO T 209, Rice Maximum Specific Gravity of Mix Separate into Loose Mix Vacuum Saturated for 15 min under 30 mm Hg Determine Bulk SSD Specific Gravity Rice = Dry Wt Dry Wt - Wt in H2O without Dry-Back Rice = Dry Wt SSD Wt - Wt in H2O 17 China - 2005
Example PoledProduction PlantAPlantB
Precision versus Accuracy Production Average Target Production Average Target PlantA PlantB
Example Production Average Target Typicaly, Asphalt Contentproduction St.Dv. =0.20, suchthat Tolerance=±0.40 AsphaltContent
Mix Verification First Day of Production (Lot 1) 3 to 4 HMA Samples, determine: Gradation & Asphalt Binder Content (P b ) Voids (V a ) & VMA 3 to 4 Pavement Samples, determine: In-place Density Smoothness
QA Plan Mixloksgod. Whatnow?
QA Plan Once the basic plant parameters are in place we don t have to run all the same tests at same frequency. QC tests are not the same as Acceptance tests. Acceptance may be on Air Voids QC may be AC and gradations, MTD, etc. Frequency of testing can change based on variability. We can run 4 QC test for every Acceptance test.
QA Plan Once the basic plant parameters are in place to produce the mix we should run tests to check input and output of the plant and only randomly verify acceptance criteria. Example Acceptance Air Voids QC AC content, gradation, MTD. All can be done at different frequencies. AC content 4 samples Gradation 2 samples MTD 2 samples Air Voids 1 sample If results are outside limits do additional testing.
Plant Operations Real QC is plant operations. A well Run plant is not out of control. 25 China - 2005
Keep stock pile separate to reduce gradation problems 26 China - 2005
Stockpiling Operations 27 China - 2005
Contamination, keeping stockpiles separate
Wind Screen for Belt Scale
Is the plant kept clean and everything clearly labeled
What goes in to a Plant comes out!
Paving and Compaction Segregation Reduction Paver Operations Compaction
Paving Operation 35 China - 2005
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Compaction 40 China - 2005
Causes of Distress Moisture Damage Segregation Non-uniformity in Materials Good compaction and uniformity in mat density can help mitigate these propblem.
Can we continue to put people on the roadway doing the same old tests.
Does this one test represent the entire roadway.
One approach is Intelligent Compaction GPS antenna GPS reference station (Trimble) BW 174 Asphalt Manager equipped with BCM05 and GPS
What is intelligent compaction? Automatic adjustable compaction equipment Usage of Continuous Compaction Control, CCC Selection of the most suitable equipment
GPS / positioning with reference station
Improved data can reduce cores Analysis Statistical data Surface plot Curve diagram Make printouts (simulator files is marked). Save to PDF file (except simulator files).
Sakai IC Roller Project Roller Passes Shoulder (Supported) Paving Direction Longitudinal Joint Courtesy Sakai America
At the mix plant are there other process that can be part of a QA program?
Plant automation is available to automatically measure and record what is going on. Automatic belt sampler and sieve analysis.
Continuous recordation of all the plant operations going to computer records.
In line viscometer for verification of binder
No more dials and knobs in the modern plant. 54
Computer recordation
QA of the Future The QA will all be tied to Internet. Direct down load of info to the owner. Posting of data immediately to all parties. Faster review and resolution of discrepancies.
Design Build Warrant Maintain - The Final QA? Long Term Warranty Performance based contract Guarantees product integrity Contractor responsible for repair of defects or replacement Warranty Period Pre specified for repair defects Present Warranty workshops to states.
Not Every Day is a Good Day! 58 China - 2005
Or even half good 59 China - 2005
I know it ll hold just one more TON! 60 China - 2005
and beyond! Cannot continue on same path of regulate and enforce Cannot continue to police contractors trying to catch them in the act System needed to match contractor s priorities inline with agency s Quality and long term performance
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