Pennsylvania’s Experience with Implementing AASHTO PP 65

Neal Fannin Pavement Materials Engineer

PADOT

ASR - Background

• In 2012 the PADOT Lab was asked to investigate two roadway sections in southeastern PA that were failing prematurely.– Dist. 6 on SR 0202 and SR 0422.

• Cores were taken and it was determined that ASR reaction was a major contributing factor in the deterioration

• The aggregates used in the concrete had been tested using AASHTO T 303 and found to be nonreactive.

ASR - Background

• Workgroup formed in September 2013.

• Included representatives from FHWA, PACA, ACPA and CABA/PPA

• Identified most recent guidance from FHWA for specification development –AASHTO PP 65.

• Decision was made to test all our aggregate sources using ASTM C1293 prism test.

• An interim special provision was immediately implemented to mandate all aggregates to be mitigated for ASR using our current guidelines.

ASR – Current Requirements• Initially implemented in 1992 via SSP.

• AASHTO T-303 – Accelerated Mortar Bar Testing• 14d (in solution) – 0.10% max expansion (AASHTO TP-14 in 1992)

Generally good predictive test method and used by many states (or a companion ASTM test method, C-1260.

– Can and does generate inaccurate results

• No re-qualification testing required Currently.

ASR – Current Requirements

• One or more reactive aggregates (>0.10% expansion):– Pozzolans as cement replacement

• Flyash– 15-25%– 20% minimum if expansion is greater than 0.40%

• GGBFS– 25-50%– 40% min if expansion is greater than 0.40%

» Spec currently prohibits combining GGBFS and Flyash• Silica Fume

– 5-10%• Blended cements – Type 1S or 1P• Low alkali (<0.60%) cement• Independent testing

ASR - Background

• Over 400 aggregate sources needed to be tested.

• A large moist room was installed in the lab, private labs contracted, and testing started.

– Phase 1 (T-303 expansions ≤ 0.15%) Completed 2015.

– Phase 2 (T-303 expansions > 0.15%) in progress.– To be completed very soon.

ASR

• ….getting into AASHTO PP-65 – Level of Risk

Worst Case Scenario

ASR –Asset Type Determination

AASHTO PP-65 Proposed Pub 408 SectionsStructure Class Consequences Acceptability of ASR Structure/Asset type Publication 408

Sections

S1 Safety and future maintenance consequences

small or negligible

Some deterioration from ASR may be

tolerated

Temporary structures. Inside buildings.

Structures or assets that will never be exposed to water

627, 620, 621, 624, 627, 628 643, 644, 859, 874, 930, 932, 934, 952, 953,

1005S2 Some minor safety, future

maintenance consequences if major deterioration were to

occur

Moderate risk of ASR acceptable

Sidewalks, curbs and gutters, inlet tops,

concrete barrier and parapet. Typically

structures with service lives of less than 40

years

303, 501, 505, 506, 516, 518, 523, 524, 525, 528, 540, 545, 605,607, 615, 618, 622, 623, 630, 633, 640, 641, 658, 667, 673, 674, 675, 676, 678, 714, 875, 852, 875, 910, 948, 951, 1025, 1001, 1040, 1042, 1043, 1086, 1201, 1210,

1230, Miscellaneous

Precast Concrete

S3 Significant safety and future maintenance or replacement

consequences if major deterioration were to occur

Minimal risk of ASR acceptable

All other structures. Service lives of 40 to 75 years anticipated.

530, 1001, 1006, 1031, 1032, 1040, 1080, 1085, 1107, MSE walls,

Concrete Bridge components and Arch Structures

AASHTO PP-65: Level of Prevention

AASHTO PP65 – Minimum Levels of SCM’s

Industry concernsStructure classification 3 (mostly bridge items) but would include long life concrete pavements, and an R3 highly reactive aggregate

Within current Pub 408 limits

ASR – Industry Concerns

• Will the new specifications result in:– Geographic regions where only R3 aggregates are located (primarily D3/4)– Finishing

• Will these mixes be difficult to finish• Will bleed water be trapped

– Durability issues• Flatwork scaling issues?

– Strength gain, esp. during late season placements• Could impact schedules, payment etc.• May need to consider allowing for acceptance at 56-d as with AAA-P SSP.

– Prestressed or high strength precast concrete• Detensioning strengths

– P3 project has producers taxed as is with turning forms over to meet demand.

Current Google Map Plots – T303 and CPT (Phase 1)

All AASHTO T-303 and ASTM C1293Results have been entered into a GoogleMaps file. Color coding is being added to distinguish between R0, R1, R2 and R3 aggregate reactivity classes for the T-303 and C1293 tests.

In the future, we hope to have the mapping feature available in eCAMMS to compare source information, including ASR data.

ASR Workplan

• PennDOT met with Industry (PACA-ACPA and CABA/PPA) to hear their concerns.

• PennDOT agreed to allow industry to develop an ASR Workplan to incorporate higher prevention level (Y and Z) mixes into several projects as control sections – Evaluate during placement and finishing– Periodic project field views by an industry/Dept. workgroup to document

findings.

• ASR workplan accepted by Deputy Secretary

ASR Workplan

• Project Criteria– Issues related primarily to flatwork and time of year

• Pavements, sidewalks• Precast segments with large flatwork surfaces

– Box Culvert end section apron (up to 6 KSI)– Sound Barrier

• Prestressed Beams (up to 10KSI)– Evaluate set times, detensioning and 28-d strengths

– Late season project field placements• For field projects to evaluate worst case strength gain

– Placement Late October or November 2016– Use and evaluation of penetrating sealers – Prevention Level Y and Z test sections

ASR Placement Matrix

PAVEMENT Test Section CONTROL PAVEMENT Test Section Y PAVEMENT Test Section ZStandard Department approved

Class AA concrete.450 Foot Tangent Section

Y Level of Prevention450 Foot Tangent Test Section

Z Level of Prevention450 Foot Tangent Test Section

225 feet No surface penetrating sealer 225 feet No surface penetrating sealer 225 feet No surface penetrating sealer

225 feet Surface penetrating sealer 225 feet Surface penetrating sealer 225 feet Surface penetrating sealer

SIDEWALK Test Area CONTROL SIDEWALK Test Area Y SIDEWALK Test Area ZStandard Department approved

Class AA concrete.1/3 Project Square Yards

Y Level of Prevention1/3 Project Square Yards

Z Level of Prevention1/3 Project Square Yards

Field Project Locations

• District 5– ECMS E88385

• Borough of Fleetwood, Berks Co.• Class AA – sidewalk

– Placement November 3rd• District 12

– ECMS 91038: SR 0119-A03 Westmoreland Co.• Class AA 12” PCC mainline pavement• Placements October 23rd and 25th

ASR Workplan - General Outline

• Consistency of Reviewers• High level of review and documentation including photographs

– Maintenance (deicing salt) applications documented• Includes precast and prestressed concrete mock-ups• Initial observations

– Finishing– Strength gain/final strengths

• End of 1st Quarter review– Scaling or other issues for flatwork

• Advance specifications or adjust/re-circulate CT.• EDUCATION/TRAINING!

ASR Workplan – Placement Observations

• Strength gain from trial batching – SR 119 Westmoreland Co.– Mainline PCC – Class AA– TRIAL BATCH DATA

PL-Y PL-Z PL-Y PL-Z50% GGBFS 65%GGBFS 25% FA 35% FA

w/c ratio 0.45 0.45 0.434 0.425Time of Set 6 HR 56 min 7 hr 33 min 5 hr 23 min 6 hr 43 min

7 day 3865 3395 3400 267514 day 4625 4205 3850 288528 day 5335 4795 4355 368556 day 5895 5680 4895 4415

Production Breaksw/c ratio 50% GGBFS 65%GGBFS 25% FA 35% FA 15% FAw/c ratio 0.417 0.417 0.417 0.417 0.417

3 day 3068 2399 4204 3334 37647 day 4315 4335 3980 4495

28 day 5590 5715 5375 5455

ASR Workplan - Observations

• Strength gain from trial batching – Borough of Fleetwood – Sidewalk- Class AA

Design BreaksPL-Y PL-Z PL-Y PL-Z PL-Y PL-Z

15% FA 25% FA 35% FA 25% GGBFS 50% GGBFS 65% GGBFS3 day 1840 1785 18277 day 2310 2358 2262 4572 4563 5661

28 day 3149 3419 3563 6053 6476 785163 day 8461 6693 7691

Production Breaks15% FA 25% FA 35% FA 25% GGBFS 50% GGBFS 65% GGBFS

3 day 3727 2912 1867 3817 3954 39517 day 4356 3474 2230 4394 4795 4295

28 day 5339 4406 2827 5307 5707 584056 day 5766 4519 3000 5375 6061 6305

ASR Workplan – Initial Observations – SR 119• SR 119 – Westmoreland Co.

– PL-Z slag mix had edge spalling at 24-hrs for relief joints.

– Minimal bleed water, esp. with Z mixtures

– Control (25% slag) mix was noted to be coarser than the other slag mixes to finish/float.

– The vibrators were turned down in the 65% slag area because of excess grout being generated on the surface.• Lead to the need to fill in concrete over the dowel baskets because of

consolidation and settlement issues.

– Overall, no major finishing issues encountered.

– Slower strength gain with Z mixtures as anticipated from trial breaks

– All met minimum 2000 psi concrete strength at 3-d for construction vehicle loading!

Tined / Curing Compound applied – SR 119 Comparisons

35% FA > 25% FA 50% Slag > 65% Slag

Borough of Fleetwood – District 5

25% Flyash 25% Slag

Control Mixtures. Photos of PL Y and Z mixtures not presented here. Photos to illustrate project type/location

Questions – Comments – Concerns?