Pennsylvania’s Experience with Implementing AASHTO PP 65 · ASR Workplan – Initial Observations...
Transcript of Pennsylvania’s Experience with Implementing AASHTO PP 65 · ASR Workplan – Initial Observations...
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 –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 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!
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