Presentation by Cathrina Barros of Caltrans on Testing Accreditation and Independent Assurance delivered at the CalAPA Fall Asphalt Pavement Conference Oct. 24, 2013 in Sacramento, Calif.

1. CTM to AASHTO
Testing, Accreditation and Independent
Assurance
Cathrina Barros, PE
CT Independent
Assurance Program

2. Why?

3. Superpave
AASHTO/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 Aggregates
201,
202
T 30
Mechanical Analysis of Extracted Aggregate
201,
202
T 335
Determining the Percentage of Fracture in Coarse
Aggregate
205
T 84
T85
Specific Gravity and Absorption of Fine Aggregate
207
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
Flat Particles, Elongated Particles, or Flat and

4. Superpave
AASHTO/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 312
Preparing 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

5. Superpave
New Test Methods
AASHTO
T 312
T 324
Preparing 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

6. T 312 – Superpave Gyratory
Compactor
Ram pressure
600 kPa
150 mm diameter mold
1.25° External
*1.16° Internal
30 Gyrations/Minute

7. Superpave Gyratory Compactor
Pine SGC
Model AFG2A
Troxler SGC
Model 4140

8. T 324 – Hamburg Wheel Tracker
PWS
Hamburg Wheel Tracker

9. Laboratory Equipment
Hamburg Wheel Tracker
1 Pass
Wheel
1 Pass
CT Specifications require 25,000 passes during testing

10. 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 Point
No. 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

11. HMA Mix Design Requirements
Quality
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
CT371
AASHTO T 283

12. HMA Mix Design Requirements
Per SP-2:
 VFA (Voids filled with
Asphalt)
 VMA (Voids in Mineral
Aggregate)
 Dust Proportion
 All by total weight of
mix (TWM)

13. Aggregate QC Requirements
Quality
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

14. 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

15. 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 AASHTO T283
(minimum dry strength (freeze-thaw required)
& minimum wet
strength)
CT 371

16. AASHTO T 176 vs. CT 217
T 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.


17. CTM in Superpave Specification
 CT
125: Sampling
 CT 202: Fractionation Gradation
 CT 204: Plasticity Index
 CT 368: OGFC
 CT 375: % TMD
 LP-9: RAP Gradation
 LP-10: Crumb Rubber Tests
 LP-11: Rubber Binder Viscosity

18. Caltrans IA Program
Tester Qualification
 Laboratory
Accreditation

◦ District IA Staff
◦ Local Assistance IA
Staff under METS

Reference Sample
Program
http://www.dot.ca.gov/hq/esc/Translab/ofpm/IAP.htm

19. Superpave and the Caltrans IA
Program
◦ Effects to the IA Program
 No change in current requirements in:
Accrediting laboratories
Certifying technicians
 Change in IA practice:
Know both AASHTO and CT Test
Methods
Certification
 CTM = Certificate of Proficiency (TL-0111)
 AASHTO = “witness” statement (development stage)

20. 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”

21. 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

22. IA
Proficiency
Certificate

23. Questions?