CTM to AASHTO Testing, Accreditation and Independent Assurance

Cathrina Barros, PECT Independent Assurance Program

Why?

SuperpaveAASHTO/ASTM vs CTM

AASHTO/ASTM

Description(Aggregate Tests) CTM

T 11 Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing

201, 202

T 27 Sieve Analysis of Fine and Coarse Aggregates201, 202

T 30 Mechanical Analysis of Extracted Aggregate201, 202

T 335 Determining the Percentage of Fracture in Coarse Aggregate 205

T 84 Specific Gravity and Absorption of Fine Aggregate 207

T85 Specific Gravity and Absorption of Coarse Aggregate 206

T 176 Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test 217

T 304 Uncompacted Void Content of Fine Aggregate 234

D 4791 Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate 235

SuperpaveAASHTO/ASTM vs CTM

AASHTO/ASTM

Description(Mix Test)

CTM

T 209 Theoretical Maximum Specific Gravity and Density of Hot Mix Asphalt (HMA) 309

T 269 Percent Air Voids in Compacted Dense and Open Asphalt Mixtures

308, 309

T 275 Bulk Specific Gravity of Compacted Hot Mix Asphalt (HMA) Using Paraffin-Coated Specimens 308

T 283 Resistance of Compacted Hot Mix Asphalt (HMA) to Moisture-Induced Damage 371

T 308 Determining the Asphalt Binder Content of Hot Mix Asphalt (HMA) by the Ignition Method 382

T 312Preparing and Determining the Density of Hot Mix Asphalt (HMA) Specimens by Means of the Superpave Gyratory Compactor

None

T 324 Hamburg Wheel-Track Testing of Compacted Hot Mix Asphalt (HMA) None

T 329 Moisture Content of Hot Mix Asphalt (HMA) by Oven Method 370

Superpave New Test Methods

AASHTO

T 312 T 324Preparing and Determining the Density of

Hot Mix Asphalt (HMA) Specimens by means of the Superpave Gyratory Compactor

Hamburg Wheel-Track Testing of Compacted Hot Mix Asphalt

No Modification Modified

Utilized for HMA Mix Design on the basis of Volumetrics

Utilized to determine the Rutting and Stripping Resistance of HMA

NO CTM equivalent No CTM equivalent

T 312 – Superpave Gyratory Compactor

1.25° External

Ram pressure600 kPa

30 Gyrations/Minute

150 mm diameter mold

*1.16° Internal

Superpave Gyratory Compactor

Pine SGC Model AFG2A

Troxler SGC Model 4140

T 324 – Hamburg Wheel Tracker

PWS Hamburg Wheel Tracker

Laboratory Equipment

Hamburg Wheel Tracker

1 Pass

1 Pass

Wheel

CT Specifications require 25,000 passes during testing

Superpave New Test Methods

AASHTO - Modifications

T 324

Hamburg Wheel-Track Testing of Compacted Hot Mix Asphalt (HMA)

Target Air Voids 7±1 percent

No. of Test Specimens 4

Test Specimen 6” gyratory compacted specimen

Test Temperature 122±2 °F (PG 58)

Measurements Impression per 100 passes

Inflection PointNo. of wheel passes at intersection of creep

slope and stripping slope

Testing Shut off 25,000 passes

For RHMA test specimens

SGC ram pressure may be increased to a maximum 825 kPa

Held at constant height for a maximum of 90 minutes

HMA Mix Design RequirementsQuality Characteristic

AASHTO Designation

CT Test Method

Air Void Content (%)

AASHTO T 269 CT 308, 309

Gyration Compaction

AASHTO T 312 n/a

Voids Filled with Asphalt (VFA)

SP-2 n/a

Voids in Mineral Aggregate (VMA)

SP-2 n/a

Dust Proportion SP-2 n/a

Hamburg Wheel Track

AASHTO T 324 n/a

Moisture Susceptibility

AASHTO T 283 CT371

HMA Mix Design Requirements

Per SP-2:VFA (Voids filled with

Asphalt)VMA (Voids in Mineral

Aggregate)Dust ProportionAll by total weight of

mix (TWM)

Aggregate QC RequirementsQuality Characteristic

AASHTO Designation

CT Test Method

Aggregate Gradation

AASHTO T27 CT 201, 202

Sand Equivalent AASHTO T176 CT 217

Aggregate Moisture Content

AASHTO T329 CT 370

Percent of Crushed Particles

AASHTO T335 CT 205

LA Rattler AASHTO T 96 CT 211

Flat and Elongated Particles

ASTM D4791 CT 235

Fine Aggregate Angularity

AASHTO T304, Method A

CT 234

QC Requirements for In Place HMA

Quality Characteristic

AASHTO Designation

CT Test Method

Asphalt Binder Content (%)

AASHTO T308, Method A

CT 382

HMA Moisture Content (%)

AASHTO T329 CT 370

Air Void Content(%) AASHTO T269 n/a

Gyration Compactions

AASHTO T312 n/a

Voids in Mineral Aggregate (VMA)

SP-2 n/a

Voids Filled with Asphalt (VFA)

SP-2 n/a

Dust Proportion SP-2 n/a

QC Requirements for In Place HMA

Quality Characteristic

AASHTO Designation

CT Test Method

% of TMD by core n/a CT 375

% of TMD by nuclear gage

n/a CT 375

Hamburg Wheel Track

AASHTO T 324 (Modified)

n/a

Moisture susceptibility (minimum dry strength & minimum wet strength)

AASHTO T283 (freeze-thaw required)

CT 371

AASHTO T 176 vs. CT 217T 176, “Plastic Fines in Graded Aggregates and Soils by

Use of the Sand Equivalent Test”T 176 allows:

◦ Manual shaker◦ SE solution with formaldehyde◦ Two allowable methods to prepare samples

Specifications require the use of a “sand reader indicator” and does not allow manual shaking and SE solutions with formaldehyde

CT test method requires working solution to be discarded after 2 weeks. AASHTO T 176 allows 30 days.

CTM in Superpave Specification

CT 125: SamplingCT 202: Fractionation GradationCT 204: Plasticity IndexCT 368: OGFCCT 375: % TMDLP-9: RAP GradationLP-10: Crumb Rubber TestsLP-11: Rubber Binder Viscosity

Caltrans IA ProgramTester

QualificationLaboratory

Accreditation◦ District IA Staff◦ Local Assistance

IA Staff under METS

Reference Sample Program

http://www.dot.ca.gov/hq/esc/Translab/ofpm/IAP.htm

Superpave and the Caltrans IA Program

◦Effects to the IA Program No change in current requirements in:

Accrediting laboratoriesCertifying technicians

Change in IA practice:Know both AASHTO and CT Test Methods

Certification CTM = Certificate of Proficiency (TL-0111) AASHTO = “witness” statement (development

stage)

Superpave Laboratory Accreditation

Current requirements from IA Manual apply

Participation in Caltrans’ RSP Submittal of CLAM Laboratory inspection

New requirements Laboratories testing aggregate and

preparing mix design, “must be qualified under AASHTO and the Department’s Independent Assurance Program”

Superpave Technician Certification

Current requirements from IA Manual still apply associated with a laboratory performs written and proficiency tests Certificate of proficiency for CTM’s

New requirements (AASHTO Test methods)

Take written exam for AASHTO exam Witness exam in front of IA personnel

AASHTO Test Methods “Witness” statement in lieu of Certificate

IAProficiency Certificate

Questions?