AASHTO SUBCOMMITTEE ON MATERIALS (SOM) TECHNICAL … · completing research project developing precision and bias statement. Report will contain additional recommendations for sample

AASHTO SUBCOMMITTEE ON MATERIALS (SOM)

TECHNICAL SECTION (TS) 2c ASPHALT-AGGREGATE MIXTURES

August 7, 2013

Stateline, Nevada

2013 MEETING MINUTES

1. Call to Order/Opening Remarks/General 2. Roster – See sign-in sheets. 3. Approval of 2012 TS 2c Meeting Minutes – Approved during webinar on April 18,

2013. 4. Old Business

4.1 Review of 2012 SOM AASHTO M 156 [concurrent ballot item – modify this

specification to be a solely owned standard (see Section 4.2.1 of these minutes)]; Negative from Kentucky, comments from

Pennsylvania. Negative withdrawn by Kentucky with

understanding that Georgia, Kentucky, and Minnesota will

continue to improve this standard. Possible TS 2c ballot in 2014. AASHTO PP XYZ [concurrent ballot item – propose a new

provisional practice for initial review (see Sections 4.2.2 and 5.4.2 of these minutes)]; Comments from Kentucky, Pennsylvania, and

New York incorporated as appropriate. AASHTO T 30 [concurrent ballot item – revise this method

according to suggestions from AMRL (see Section 4.2.3 of these minutes)]; Negative from Pennsylvania, comments from

Kentucky. Pennsylvania negative considered persuasive. Tim

Ramirez (Pennsylvania) will modify T 30 for 2013 concurrent

SOM ballot (Louisiana motion, Oregon second). Add provision

to compare mechanical washing with manual washing based on

Pennsylvania recommendations and AAPRL research. Another

issue is difference in sieve surface area between T 27 and T 30. AASHTO T 164 [concurrent ballot item – modify Section A1.1.3.1

to clarify ―conditioning‖ of the ignition dish (see Section 4.3.1 of these minutes)];

AASHTO T 166 [concurrent ballot item – modify Section 6.2 to increase the maximum amount of time permitted for drying and weighing the specimen (see Section 4.3.2 of these minutes)];

AASHTO T 329 [concurrent ballot item – modify this method in various sections to standardize the usage of the term ―constant

Tech Sec 2c Page 1 of 65

mass‖ (see Section 5.6.2 of these minutes)]; Comments from

Kentucky, Pennsylvania, and New York incorporated as

appropriate. AASHTO T 329 [SOM ballot item – add thermometers to Section

5 (see Section 4.3.3 of these minutes)]; Comments from Kentucky

and Pennsylvania incorporated as appropriate. AASHTO T 331 [concurrent ballot item – modify Sections 7.1 and

8.2 to clarify the use of the apparent specific gravity and correction factor for the plastic sealing material (see Section 4.3.4 of these minutes)]; and Negative from Missouri regarding apparent

specific gravity of bags. As discussed during TS 2c conference

call/webinar, negative withdrawn by Missouri. AASHTO T 331 [concurrent ballot item – modify Section 8.2 to

permit a larger mix size and different specimen dimensions (see Section 4.3.4 of these minutes)].

4.4 Task Force Reports

4.4.1 Task Force 2c-2008-02 – The members of this group are

Kansas (Rick Kreider) and FHWA (Tom Harman and Mike Rafalowski). This task force was requested to provide a recommendation for the appropriate requirements, namely amplitude and frequency, for mechanical agitation devices in AASHTO T 209. The original charge of this group is being addressed through research conducted by the AASHTO Advanced Pavement Research Laboratory (AAPRL). Maria

Knake (AMRL) to arrange webinar with Haleh Azari

(AAPRL) to discuss AAPRL research findings concerning

amplitude, frequency, and duration of vibration on table.

4.4.2 Task Force 2c-2008-04 – The members of this group are Florida, Pennsylvania (Mr. Ramirez), and Wyoming (Mr. Harvey). This task force is responsible for developing an NCHRP problem statement for a future research project considering the variability of correction factors between ignition ovens in AASHTO T 308 when the equipment is both stationary and moved. Also, this group will consider requiring correction factors for each mixture/ignition oven combination versus allowing the use of historical data or scientific studies to suffice for those factors.

RESULT: NCHRP Project Approved. Task force retired.

4.4.3 Task Force 2c-2008-06 – Representatives from Georgia (Ms. Geary), Illinois (Mr. Lippert), and New Mexico (Mr. Simons) comprise this group, formed to consider the inclusion of additional options for the quartering procedure in AASHTO R 47. First, Chairman Baker attempted to identify the chair for this task force. Mr. Lippert asked if interest still exists in this


topic. Mr. Simons reported that the different quartering methods produce comparable results, so these additions may not be necessary. Mr. Bradbury responded that the issue remains pertinent in his state for quality control laboratories. Chairman Baker decided that the group should continue with the former members as well as Messrs. Bradbury and Walker. Mr. Bradbury will serve as the chair for Task Force 2c-2008-06. Work continues in Maine. Experimental plan developed

by Ron Walker (Indiana) to evaluate riffle splitting. Task

force extended.

4.4.5 Task Force 2c-2010-01 – TS 2c established this task force to address AASHTO TP 82, the procedure for determining the Gmb of compacted asphalt mixtures using water displacement measured by a pressure sensor. Representatives from AASHTO (Ms. Azari), FHWA (Mr. Corrigan), the Gilson Company (Jim Bibler), and Washington (Chairman Baker) constitute this group. Task Force 2c-2010-01 was charged to generally improve the procedure and incorporate the comments from the 2009 SOM ballot into TP 82 as appropriate. Specifically, more details are needed on the water displacement measurement equipment. This group will also evaluate the precision of this provisional test method and compare the values to existing equipment utilized to measure Gmb. Chairman Baker reported that the work of the task force continues. Matt Corrigan (FHWA) reports that data continue

to be collected. Ask Chairman Baker about status.

4.4.6 Task Force 2c-2010-02 – This task force involves AASHTO T 166 and T 331. The FHWA Asphalt Mixture ETG evaluated AASHTO T 166 and compared it to other procedures for measuring Gmb. The ETG recommended the expanded use of the vacuum sealing procedure, AASHTO T 331. Task Force 2c-2010-02 will consider the report on these items and the resulting effect on the applicable TS 2c standards. This group includes representatives from the consulting industry (Mr. D’Angelo), FHWA (Mr. Bukowski), Idaho, Indiana (Mr. Walker), Virginia (Mr. Bailey), Washington (Chairman Baker), and Wyoming (Mr. Harvey).

Chairman Baker announced that Mr. Santi will replace Jeff Miles as the Idaho representative on this task force. Also, Ms. Geary will replace the retiring Mr. Harvey and chair the group. Mr. Bukowski mentioned that an FHWA ―Tech Brief‖ concerning this issue is available for review. Chairman Baker reported that the work of this group continues. Pennsylvania

and Indiana report significant differences between

procedures, paraffin sealing and vacuum sealing. Ron


Walker (Indiana) reported extensive testing that revealed a

difference of approximately 3 percent. Major issue is

recommendation to use vacuum sealing when water

absorption exceeds 1 percent.

Georgene Geary (Georgia) plans to raise subject at September

meeting of Mix ETG. John Bukowski (FHWA) responds that

issue has been discussed at length within ETG. Discussion of

FHWA Tech Brief. Work of task force continues to identify

standards affected by recommendations in Tech Brief and

modify those standards for future ballot.

4.4.7 Task Force 2c-2012-01 – As documented in Section 4.2.4 of these minutes, TS 2c established this task force to address the negative votes and comments for AASHTO T 324 as received on the 2010 SOM ballot. Additionally, the group will make general improvements to the method and include accommodations for the APA Jr. Representatives from Colorado, FHWA (Mr. Corrigan), Illinois (Mr. Lippert), Louisiana (Mr. Abadie), Montana, Pennsylvania (Mr. Ramirez), Texas (Mr. Hazlett), and Utah (Mr. Andrus) constitute this task force. Scott Andrus, Chair Interest from Ronald Collins Ron Collins inquired about

development of calculations for Stripping Inflection Point (SIP).

Revised T 324 as updated by task force to address previous

negative votes and comments to be presented on 2013 concurrent

SOM ballot (Louisiana motion, Montana second). Not all issues

were resolved. Scott Andrus (Utah) recommends another task

force to consider inclusion of APA, Jr. Insufficient data exist to

fully address APA, Jr. Pennsylvania uses APA, Jr. and supports

its inclusion in T 324. Standard was developed for single device,

but more options are now available. Haleh Azari (AAPRL) is

completing research project developing precision and bias

statement. Report will contain additional recommendations for

sample preparation and handling. Matt Corrigan (FHWA) to

develop NCHRP research statement comparing different types of

loaded wheel testers.

4.4.8 Task Force 2c-2012-02 – The other task force created by TS 2c in 2012 involved AASHTO PP XYZ. This practice addresses vacuum-drying of compacted asphalt mixture specimens. As presented in Section 4.2.2 of these minutes, this group will modify the standard according to the comments received on the 2012 TS 2c ballot. The task force will also compare the differences between the InstroTek and Troxler units and make the method more accommodating to multiple manufacturers. AASHTO PP XYZ will appear on a concurrent SOM ballot later this year. Task


Force 2c-2012-02 includes representatives from FHWA (Mr. Corrigan), InstroTek (Mr. Regimand), Louisiana (Mr. Abadie), New Mexico (Mr. Simons), Troxler Electronic Laboratories (Mr. Reaves), and Virginia (Mr. Bailey). Mr. Bailey will serve as the task force chair. Task force retired.

5. New Business

5.1 AMRL Issues 5.1.1 AASHTO R 47 (2008) – Reducing Samples of Hot Mix Asphalt

(HMA) to Testing Size

Section: 7.3 Revise: ―Noncontact Temperature Device (optional): a noncontact temperature device suitable for determining the temperature of a heated splitter.‖ Rationale: A noncontact temperature device is not necessary if the user does not heat the splitter, therefore it should be optional. The current section does not given any requirements for the accuracy or readability of the device. The issue should be discussed further to determine suitable requirements for the infrared thermometer. Revised R 47 as suggested by AMRL to

be presented on 2013 concurrent SOM ballot (Minnesota

motion, Illinois second).

5.1.2 AASHTO T 164 (2011) - Quantitative Extraction of Asphalt

Binder from Hot Mix Asphalt (HMA)

Section: 12.4 and 25.2.6 Revise 12.4: ―Start the centrifuge revolving slowly, and gradually increase the speed to a maximum of 3600 r/min until solvent ceases to flow from the drain. Allow the machine to stop; add 200 mL (or more as appropriate for the mass of the sample) of trichloroethylene, methylene chloride, normal-propyl bromide, or terpene extractant, and repeat the procedure. Use sufficient solvent additions (not less than three) until the extract is not darker than a light straw color (when viewed against a white background). Collect the extract and the washings in an appropriate container for mineral matter determination.‖ Revise 25.2.6: ―Repeat Section 25.2.5 until the solution is a light straw color (when viewed against a white background) and the aggregate is visually clean…‖ Rationale: Method B specifies that the solvent shall be checked against a white background (Section 16.2.5). All of the


methods should use the same criteria. Suggested changes to

be adopted editorially.

5.1.3 AASHTO T 164 (2011) - Quantitative Extraction of Asphalt

Binder from Hot Mix Asphalt (HMA)

Section: A1.3.2.1 Revise A1.3.2.1: ―Place the extract in a previously tared and calibrated flask. Place the flask in a constant-temperature bath controlled to ±0.1°C (±0.2°F), and allow it to reach the temperature at which the flask was calibrated. When the desired temperature has been reached, fill the flask with solvent at the same temperature. Bring the level of the liquid in the flask up to the neck; insert the stopper, making sure the liquid overflows the capillary, and remove the flask from the bath. Wipe the flask dry; determine the mass to the nearest 0.1 g,, and record this mass as the mass of flask plus extract, M2. and record the result as the mass of the contents of the flask, M1. A1.3.2.2 After the extracted aggregate has dried to a constant mass and cooled, determine the mass to neareast 0.1 g. Record the mass of the initial sample minus the mass of the extracted aggreagate as the mass of the asphalt binder and fines in the extract, M2.‖ Adjust subsequent section numbers accordingly. Rationale: The current standard does not have a procedure to find M2 and incorrectly lists M1 as M2. Revised T 164 as

suggested by AMRL to be presented on 2013 concurrent SOM

ballot (Illinois motion, Pennsylvania second).

5.1.4 AASHTO T 269 (2011) – Percent Air Voids in Compacted

Dense and Open Asphalt Mixtures

Section: 6.2 and new Section 6.2.3 Revise 6.2: ―For open asphalt mixture, use either one of the following methods:‖ Add new Section 6.2.3 ―Paraffin Sealing Method – Use T 275 for samples that contain open or interconnecting voids or absorb more than 2.0 percent of water by volume, as determined by T 166.‖ Rationale: There is no guidance within the standard for determining the bulk specific gravity using T 275, yet there is for T 331. Suggestion withdrawn by AMRL.


5.1.5 AASHTO T 331 (2010) – Bulk Specific Gravity and Density of

Compacted Hot Mix Asphalt (HMA) Using Automatic Vacuum

Sealing Method

Section: 5.9 Revise: ―Vacuum Gauge (StandardizedCalibrated)—The calibrated standardized vacuum gauge shall be capable of being placed inside the automatic vacuum sealing device to verify vacuum performance and seal integrity. The gauge shall have a minimum range of 10 to 0 mmHg (10 to 0 torr) and readable to 1 mmHg (1 torr) increments as a minimum." Rationale: “Standardize” more accurately describes the activity to be completed. Suggested changes to be adopted

editorially.

5.2 NCHRP Issues – See Section 4.4.7 of these minutes.

5.3 Scan Proposals – None offered. Forward any ideas to Chairman

Baker by October.

5.5 Proposed New Standards – Chairman Baker introduced two new standards originating from Louay Mohammad and the Louisiana Transportation Research Center (LTRC). Both methods were included as attachments in the 2012 TS 2c agenda. These procedures were developed from NCHRP 9-40, Optimization of Tack Coat for HMA Placement. Chairman Baker questioned the appropriate technical section to be responsible for these standards. Mr. Harvey replied that a new technical section for pavement preservation items has been proposed, but this issue is still being debated. Chairman Baker decided that TS 2c will assume responsibility for these methods at present. Mr. Harvey noted that the FHWA Asphalt Mixture ETG has reviewed the draft procedures, and Mr. Corrigan reported that the NCHRP 9-40 panel has reviewed them as well. Mr. Harvey remarked that the testing devices described in the proposed standards differ from the NCAT-recommended version of the apparatus.

5.5.1 TP 2012-01A – The first standard originating from NCHRP 9-

40 is a test for determining the interlayer shear strength of asphalt pavement layers. LTRC developed the Louisiana Interlayer Shear Strength Tester to characterize the interface shear strength of cylindrical specimens. Chairman Baker announced that this procedure will be presented on a TS 2c

ballot in 2013.

5.5.2 TP 2012-02B – The second method concerning tack materials is a test for determining the tack coat quality of asphalt pavement in the field or laboratory. The procedure involves


desiccating a tacked surface, adjusting the temperature of the surface to the specified value, and applying a compressive load to the tacked pavement surface. The maximum tensile strength is measured to determine the quality of the material. Again, Chairman Baker decided to include this proposed standard on a TS 2c ballot next year. Matt Corrigan (FHWA) is not aware

of status of these methods. Ask Chairman Baker about

status.

5.6 Revisions Suggested by the Western Alliance for Quality Transportation Construction (WAQTC)

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

Add symbols for air voids (Va), and the specific gravities (Gmb and Gmm). Add alternate formula for calculating Va Revised

T 269 as suggested by WAQTC to be

presented on 2013 concurrent SOM ballot.

T 287; Asphalt Binder Content of Asphalt Mixtures by the Nuclear Method

Originally constant mass was not fully defined in two locations, added references to existing drying procedures. Revised T 287

as suggested by WAQTC to be presented on

2013 concurrent SOM ballot.

T 305; Determination of Draindown Characteristics in Uncompacted Asphalt Mixtures

Originally constant mass was not fully defined; added reference to T 255 which has complete instructions on achieving constant mass. Revised T 305 as suggested by

WAQTC to be presented on 2013

concurrent SOM ballot.

T 319; Quantitative Extraction and Recovery of Asphalt Binder from Asphalt Mixtures

Originally constant mass was not fully defined; added necessary language. Revised

T 319 as suggested by WAQTC to be

presented on 2013 concurrent SOM ballot.

5.7 Standard Requiring Reconfirmation – T 319 is due for reconfirmation

but will be addressed on 2013 concurrent SOM ballot as described

above.

5.8 Provisional Standard Requiring Extension – TP 72 extended for two

years by TS 2c voice vote (Georgia motion, Illinois second).

5.10 TS 2c Ballot Items – The following standards are scheduled for a TS

2c ballot in 2013:

5.10.1 AASHTO T 305 – As noted in Section 5.7 of these minutes, AASHTO T 305 will require reconfirmation in 2013.


5.10.2 AASHTO TP 2012-01A – As noted in Section 5.5.1 of these minutes, AASHTO TP 2012-01A will be presented on a technical section ballot next year for initial review. This test determines the interlayer shear strength of asphalt pavement layers.

5.10.3 AASHTO TP 2012-02B – As documented in Section 5.5.2 of

these minutes, AASHTO TP 2012-02B will also appear on a TS 2c ballot in 2013 for initial review. This provisional method evaluates the tack coat quality of asphalt pavement in the field or laboratory.

Two additional items submitted by WAQTC do not appear in agenda. Address these

issues at 2014 mid-year conference call/webinar.

Dave Lippert (Illinois) presentation on total-recycle asphalt.

No volunteers for TS 2c research liaison.

Wait for Chairman Baker before scheduling 2014 TS 2c conference call/webinar. 6. Adjourn













AASHTO R 47 (2008) – Reducing Samples of Hot Mix Asphalt (HMA) to Testing Size

Section: 7.3 Revise: “Noncontact Temperature Device (optional): a noncontact temperature device suitable for determining the temperature of a heated splitter.”

Rationale: A noncontact temperature device is not necessary if the user does not heat the splitter, therefore it should be optional.


Documents

AASHTO SUBCOMMITTEE ON MATERIALS (SOM) TECHNICAL … · completing research project developing precision and bias statement. Report will contain additional recommendations for sample