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Details of Minutes

Apr 19, 2006: MC² Meeting - St. Louis, MO



MCC MEETING MINUTES ST. LOUIS, MISSOURI APRIL 19-20th 2006

John Staton – Opening Remarks; Introductions

State Reports – Bridge Railing Cracking, Existing Problems and Solutions

Hal Wakefield – Framing the Concrete Bridge Rail Cracking Problem. IDOT formed a team to review barrier cracking. Illustrated many different types of distresses occurring in barrier walls. Cracking in slipped parapets. Did not see any in cast-in-place barriers. Lack of consolidation was found where there was honeycombing. Held industry meetings and tried to come up with solutions to these problems. Changes were made in steel design. Handfinishing was not allowed to cover up honeycombing, because it would most likely be replaced. Slip formed barriers had many problems with little to no cover of the steel reinforcement. Required coring to verify quality on interim projects. Improved efforts on industry part, but continue having problems. Conclusion was made that slip forming not reliable. 50% failure after a lot of effort on correcting the problems. Management is requesting to make it work. Method specifications are being proposed to help resolve the issues.

Illinois – Brian Pfeifer Specification Changes – Well graded aggregates, travel speed max 4 ft/min, uniform delivery, dry run over full distance, 7-day wet cure, formed 4-ft. around light standards. Joints – 14 – 20 ft. spacing, saw cut the full thickness, aluminum sheets required at bottom portion, bar intersections 100 % tied, FRP bars across joints to provide rigidity, adding stiffening reinforcement, changed details. Mix Design – Min of 605 pcy cement, up to 20% C ash, 15% F ash, 25% Slag. Coring requirements, 3 Cores per 100 ft, any suspect locations, no voids allowed around bars. Special provisions provided since moratorium. Did not allow hand finishing. McKinley Bridge had a trial run and was successful. Future – Continue using new special provision, IDOT challenges is inspection and consistency and continued efforts.

Indiana – Tom Nantung Bridge rail cracking is somewhat of a problem, but not quantified.

Iowa – Sandra Larson Iowa went to an optimized mix. The Class D mix was difficult to finish, difficult to entrain air, and sluffing occurred. Poor workability leads to poor performance. Low air and poor void spacing. Solutions – well graded aggregates, less cement, and added water reducer. Used Shilstone methods to improve the aggregate gradation. Results of new mix is amazingly better than old mix. Lower cement about 100 lbs. Mix changes achieved better quality barrier rail. Current implementation – Air 7% requirement, change in mix design. Ohio – Bryan Struble Experience – Made specification changes to improve barrier rail quality. Different steel configuration, Changed top steel to 1 bar instead of 2, perform dry run, restrain steel against movement, inspect parapet for cracking. 2004 drive by evaluation – 19.5 % formed had cracks. 24.7% slipformed had cracking. There was significant cracks – vertical, horizontal, longitudinal and on top. Have concrete mixes that allow SCM replacement, WR admixtures. HPC mix do you use a mid range? They have the flexibility to choose an approved admixture.

Missouri – Me

Minnesota – Doug Schwartz Vertical cracks occur every 7-8 feet is a common occurrence. Not greatly concerned. The minimum cementitious content for railings is 570 lb/yd. 15% for flyash and 35% GGBFS. Wet cure until 45% of anticipated compressive strength obtained. Air entrainment is required. Medium barrier – contraction joints every 20 feet. Does not have incentive/disincentive. Epoxy injections are used for repairs.

Kansas – Rick Kreider (Not Present)

Michigan – John Staton Both slipped formed and fixed form construction is permitted. Total cementitious content (5.5 to 7.0 sk/cyd.). Implementing HP concrete – ternary mixes and well graded aggregates. 15% flyash, 40% ggbfs substitution, 40% ternary substitution. Apply curing compound. Joint project between Michigan Tech and Wayne State University- Causes and Cures for Cracking of Concrete Barriers. No incentives/disincentives.

Wisconsin – Jim Parry Slip form is prohibited. Problems with vertical cracks in barriers. Mix design is the same for bridge decks. Admixtures used and are the same for decks. Curing with wet burlap or burlene for 4 days. Joints are every 30 feet, but this caused severe reflective cracks in the decks; changed to cast parapets continuously. Expansive additives were tried on projects; need to ensure good mixing. Research includes the Type K cement, expansive additives, and shrinkage reducing admixtures.

Nebraska – Robert Rea (Not Present)

Oklahoma – Kenneth Seward Serious concerns of cracking in barriers. May eliminate slip formed in future. Currently no well graded aggregates, but looking into optimizing.

Georgia - Jay Page Similar problems with cracking and consolidation problems in GA. GA allows slip formed and fix formed. Contributor to problems – speed of paver, start/stop methods. Try to work with the contractors to eliminate constructability issues. Install dummy joints in prior to sawing. Temperature is a major factor in cracking potential. Mixes a min of 635 lb/yd. Fly ash max substitution 15%. GGBFS is allowed, but not often used. Curing is a spray curing. 1 gal/150 sq. ft. May take more. Admixtures are not required, but air and other specifications ensure that they are used. Require a retarder. Must be placed within 1 hour. Repair cracks by sealing. No incentive/disincentives.

Louisiana – John Eggers Not a noticeable problem, but will follow up. Excellent bridge contractors that may contribute to good workmanship. No significant differences in mix designs, designs, or other items.

South Dakota – Dan Johnston 3M fibers in decks and walls. Slipfomed rails successful. Cracking less and tighter, but still crackings. Did not adopt the fibers due to cost.

Cement technical observations – Lafarge – Does cracking problems lead to hesitancy in using ternary and blended cements? John Staton – tackling placing and curing aspects more than looking at effects of SCMs.

Holcim – Less cement used, the better. Well graded aggregate is better

Sohila Bemanian –HPC Implementation for Bridge Decks The message – Quality, Budget, and Schedule

How to achieve success – plan ahead, work together. HPC Background – Types and Causes of Bridge Deck Cracking and Case Studies. NDOT is spending $1B constructing super projects. Good opportunity for making new structures last longer. Experienced cracking on newly constructed bridge cracking prior to HPC implementation.

Carson Freeway Project

Cracking on US-95 near Las Vegas. – Used a clear curing compound, did not get good coverage, plastic shrinkage cracking occurred.

US395 – Concrete frozen and cracking occurred. Contractor took the risk and was cheaper to seal the cracks later. Disincentives were implemented to prevent poor workmanship.

HPC Task Force Created

Types and Causes of Bridge Deck Cracking. Materials/Environment Plastic Shrinkage – rate of evaporation is faster than rate of bleeding. Occurs within a few hours Prevention - Optimize the time of concrete placement, fogging the concrete immediately, 10-day wet cure. Contractors use weather meter to determine evaporation rate and is documented. Keep evaporation rates below 0.2. Fogging required. Wet curing – communicate on best practices and methods. Over weekends – document time when they came to wetting the burlap. Ensuring that everything get done and gets done properly. Wet Curing Recycling is a good way to conserve water. Wet Curing does make a difference and reduces cracks.

Thermal Cracking – Caused by thermal gradients. Pevention – Maintain less than 30 degree difference. Document and continuously check sub-structure temperatures. Put responsibility on contractor and make them document their work. Use of heaters in cold weather. Thermometers and electronic temperature measuring devices installed.

Drying – Mix Designs Mix Design optimization, well graded mix, low w/c ratios, take advantage of admixtures.

HPC Requirements – Permeability, Modulus, Wet curing, 56-day compressive, ASR, Use less cement. Careful on what is mix design requirements vs. production requirements.

Creep is additional information. Drying shrinkage is also additional info, but these tests are not conducted.

CASE STUDIES

Overcoming challenges – Pooled together to construct the best bridge possible. Liquidated damages were in the contract. Required a comprehensive plan on how to place concrete bridge decks. 100 % responsibility on contractor. Deck overlays or epoxy injection to correct mistakes. NDOT provided 5 mix designs. Cemex developed cost-effective mixes that met specifications and construction requirements. Cemex stayed involved throughout project. Significant adjustments had to be conducted to make the mix workable and pumpable. Grace was on site to change admixture sequence. Specification changes – Increased slump from 7 to 10 inches and air content from 7 to 10 %. The admixture is carboxalate admixture. Batching sequence needed to be changed. Conclusions – Need pre-pour meeting with all players involved to work on issues. HPC implementation has been a great success. Make the consequences for poor workmanship high. HPC is only successful as the batching, mixing, placing, and curing that is conducted. 10-day wet cure, temperature monitoring, training inspections. Future improvements – Batch Plant Certifications, Further mix optimization, continue training NDOT and contractor personnel, monitor performance of HPC bridge decks, Develop more options when cracking occurs. Communication is the key to success.

Answers to Questions - Do you limit the temperature difference – yes 30 degree. Total cementitious – 600 lb/cy. Since HPC implementation – no cracking occurred. Long spans did have some cracking. The 100 % contractor responsibility has not been challenged. Carboxalate admixtures are not mandated. Intergrounded blended cements would have been allowed if contractor wanted to use this. Slump loss was attributed to high absorptive aggregate. They do check the air on the deck. How much partnering does the ready mix producer and contractor do? There was a lot of necessary partnering done for these mixes.

Tuesday, October 24th was proposed as the next MCO meeting at the Rosemont in Chicago, IL. This meeting will be held a day before the International Conference of Long Life Pavements. If this occurs, then a MCC meeting will not be held. This date is tentative and final details will be posted on the web site. A list of contact information is sent around for attendees so that the correct MCC contact may be listed. A new MCC chairperson is scheduled to be elected in the fall, but may be postponed until next spring. An endorsement letter to upper management helped provide funding and support to attend the MCC meetings. Other states may want to do the same thing to get approval. The pooled fund projects have been a good avenue to get attendees to the MCC. Now that the current pooled fund is nearing its end, need to be able to keep members attending. Looking for ways to get funding and approval to keep everyone attending.

Dr. Darwin – Bridge Deck Cracking Pooled Fund Status Low cracking high performance concrete bridge decks. LC-HPC. Project Scope: 20 bridges – 13 planned for Kansas, South Dakota has 2. Composite steel girder bridges, full depth slabs, removable forms, matching bridges to serve as a control. Why LC-HPC? Chlorides and cracks. Cracks have a big impact on chloride exposure on reinforcing steel. Monolithic, conventional overlay, silica fume overlays were looked at. Crack surveys were conducted – Age influences cracks. Monolithic decks cracked less and Silica Fume overlays were the most cracked. Increasing water and cement increased cracking. Slump of concrete is higher, more cracking will occur. The lower strength mixes cracked less. Bridges constructed in the 80’s cracked less than in the 90’s. Silica fume overlays, however, had less cracking in the late 90’s due to the fogging requirements. Overall Approach – Low cement and water contents, low slump, lower ultimate strength, low evaporation rate. More early cracking means more total cracking. LC-HPC – 1-inch max aggregate, optimized gradation, etc. Alternatives to Pumping – buckets and belts are required. Pumps only used if demonstrated on an optimized mix. Consolidation requirements with gang vibrators. Machine fogging requirements. Early wet burlap cure within 10 minutes. The texture is conducted by grinding/grooving. 14 days wet cure with burlap, soaker hoses, and ploastic, Curing compound to slow the rate of evaporation. Trial slab required to demonstrate implementation of the specialized process and address problems before placement. Progress – Two LC-HPC and two control bridges constructed. First crack surveys will be conducted for this spring. Developed and distributed mix optimization program. Testing low shrinkage bridge deck mixes. Continued research. Chemically induce slump to achieve workability. The finer the pore structure the more internal stresses that occurs, thus more cracking. Mixes containing flyash crack more than non flyash mixes. Two Class C ashes and Two Class F ashes. Focus on curing and low paste content to decrease cracking. ASTM C157 is used. Look at a grade 80 slag to see its effects. A lot of variation in flyash sources and ggbfs sources. Different thermal coefficients between the girder and deck will influence cracking. Joints in bridges - big push to eliminate joints. Not currently testing ternary mixes at this point.

State Reports – Bridge deck cracking and overlay cracking.

Tom Nantung – Indiana Bridge decks, The challenges are cracking in bridge decks within a short amount of time after construction. Causes of cracking involve construction problems and poor curing methods. Challenges – Contractors do not read the specs, rely on agency to tell, bad specifications, lack of knowledge of latest construction techniques, lack of resources, penalties are too light, owner often pays for the mistakes. Materials and mixtures changes– reduce water and cement contents, optimize gradations. Design changes to help prevent cracking – Cover thickness, modified stay in place deck form placement, etc. Construction changes – Specify limits on environmental factors, concrete pumping, etc. Specification changes – address the most important parameters in the spec, address other parameters through special provisions, and other items. Emphasize consistency and move responsibility to contractors. One size does not fit all. Monitoring equipment and methods need to be implemented. How do we measure quality and how to create incentives/disincentives.

Bridge deck overlays – Latex concrete overlays, Slag cement overlays are not conducted anymore due to bad experiences. Strength, Quality Control, and Workmanship are the most important parameters.

Brian Pfeifer – Illinois Bridge Decks – Types – transverse full depth, random over entire length. Looking in material properties and environmental issues. University of Illinois – HPC and Conventional mixes , Tensile Creep, shrinkage, drying shrinkage, thermal, shrinkage, and creep influence. Structural restraints is a big factor. HPC concrete – low permeability and creep/shrinkage same as conventional. 445 Cem / 90 Flyash / 25 Mix Designs – 605 pcy cemen, Allow 25 % GGBFS, 515 cement/140 Class C (most common). Specification changes – Seminars conducted, fogging required, curing mats, soaker hoses. Placement – pumping most common, diaphragms poured 45 min. ahead, pour sequences required on certain spans. Sealant study being conducted. 5-year field and lab study. Linseed oil performs pretty well. Current discussions – Corrosion resistant reinforcement, crack or penetrating sealants, thicker deck, sacrificial deck overlay, post tensioning.

Bridge Deck Overlays 658 + Latex 564 + Microsilica Types of overlay cracking – transverse, random, tight cracks. Latex concrete mixed by mobile mixer. Microsilica pump or truck. Surface prep methods – starting required pull-off tests, no longer allowed hand held methods, now require hydroscarifications.

Very significant decrease in plastic shrinkage cracking.

Sandra Larson – Iowa Past Problems – transverse cracking, plastic shrinkage cracking. Specification Changes – Class C Mix (624 pcy), Temperature limits > 90 F or evaporation rate exceeds 0.2 lb/ft2/hr. Current implementation – Placing wet burlap within 10 minutes for 7 days, Reducing cement to 593. Challenges – Full depth cracks over pier and occasional cracking. HPC the evaporation rate shall not exceed 0.1 lb/ft2/hr. Bridge deck overlays have very little issues with cracking. Not a lot of research conducted for bridge deck overlays.

Bryan Struble – Ohio Deck placement – place concrete in a continuous pour. Concrete is usually pumped. Standard mixes – 715 lb of cement with 15% replacement on flyash, 30% slag and 50 lb less cement. HPC – flyash mix – 480 cem/150 flyash/30 sf, Slag Mix 440 cem/190 ggbfs/30 sf. QC/QA – 4500 psi design strength. Evaporation rate – 0.2 lb/ft2, HPC – 0.1 lb/ft2. Admixtures are allowed. Tried Type K cement with poor results. No corrosion inhibitors or SRA. Curing – 7 day water cure, soaker hoses, and plastic. Experience – Some bridge deck had cracking others did not. Cracking caused from autogenous shrinkage – Moisture in aggregate not available once hydration uses up moisture in paste. Research 115 bridges were evaluated – 58% no cracking, 28% minor cracking, 14% significant cracking. Conclusion – Shrinkage is a major factor, restraint of the deck, Reduce restraint – use LRFD, Consider shrinkage reducing admixtures, enforce placement and curing specifications. Continued research – lightweight aggregates and reduce autogenous shrinkage. No incentives/disincentives, use HMWM on cracks.

The video clip of the penguin pushing the other penguin into the water is priceless. Notes will commence after I quit laughing.

Overlays – 10% silica fume was too much and was reduced to 5%. Three mixes contractors can choose from. Occasionally have cracks, but not sure of the extent.

Missouri – Me

Doug Schwartz – Minnesota Placed by pumping. Cure concrete until 65% of anticipated strength. 2” low slump overlays placed on 7” structural decks. Experimenting with 30% flyash. Admixtures are approved through Doug. Experimenting with a 500 lb/yd3 using a superplasticizer, but not very successful. Method of repairing – epoxy sealers. Identify problems – gathering data, temp, wind speed, placement times. Reduce modulus of elasticity, reduce heat of hydration, well graded aggregates. Max cementitious 611 pcy. Examined pouring sequence, environmental requirements, night time pours, rate of pour, use of additives. Improved curing methods. Max curing specifications, AMS curing compound, 7-day wet cure. Homogenous white coating. Applied within ½ hour of concrete placement. Serious penalties if not conducted. Material solutions – 25 – 30 % flyash, slag, or a combination. .40 w/c ratio max., monolithic deck pours. Advantages – ASR, increased strength, improve workability, etc. Repair methods – sealing. Bridge deck overlay cracking. Use the mobile mixer. Delamination not a problem. Cement substations not allowed in bridge deck overlays. Apply membrane cure within 30 minutes after placement. No dis/incenetives. Repair by epoxy penetrant sealers.

Jim Parry – Wisconsin Transverse full depth cracking. Design – thin decks, long continuous decks, load related cracking. Construction – water addition to mix, poor consolidation, burlene cure – hothouse, lack of curing moisture. Mixture related problems – small stone, high cement w/ no SCMs, excess water in mix. No noticeable difference between concrete or steel girders. Remaining problems – piers with additional steel, cracking forms. Diagonal cracks off of the abutment. Design changes – thicker decks and different rebar configuration. Construction – 7 day wet cure, prohibit poly sheeting, emphasis on consolidation, emphasis on fogging. Concrete mixture – require 1 ½” top size stone, reduce cement content, require use of SCMs, QMP strength specifications. Other things tried: Type K cements, HPC mixes, Fibers, SRA. No success with Type K cements. Fibers were tried – Synthetic and steel. Bridge Deck Summary – 50% of structures. After adjustments has lowered cracking. Pump or Belt placement. Require a min of 15% and max of 30%. Upper limit of evaporation rate 0.2 lb/ft2/hr. Max temp is 90. Curing with fogging. 7-day wet cure. Require the use of air agents and WR. Retarders occasionally used. Prohibit the use of HRWR. No incentive/disincentives. Look more of SRA, immediate application of wet cure, slag replacements.

Overlays – Use the low slump overlay – 822 lb/yd3. No SCM’s, No evaporation control specs, 3-day water cure. Admixtures – air and WR required. Good success on low slumps. Introduce SCM’s would be something to look into.

John Staton – Michigan Ditto all other presentations.

April 20, 2006 Sandra Larson – Iowa MCO Recap. MCO – finishing up the shadow projects. Focus on deliverables and recognize further and future research. 3 states gave presentations on how the MCO project benefits their state. Deliverables : IMCP Manual, AVA User Guide, Coffee Cup Procedure, New Calorimetry Test, Test Manuals, Briefs, Incompatibility Research. 5 Focus – Permeability, Air, Strength, Workability. COMPASS collaboration is separate, but included with the MCO project. Project final report

Gomaco Inc. Representative – Dennis Clausen

Parapet Wall Cracking – Wall configuration, design, mix design, paver speed. Parapet shapes difficult to slipform. Radius works better than chamfer. Overhangs at top are the most challenging, but not impossible. Design changes to make it easier would be to widen the base slightly instead of going vertical. Steel design must have adequate cover, and too much steel can affect consolidation. Steel should be rigid to prevent movement. Vibrators – Curb and Gutter and Paver Type. Paver type vibrators should help improve consolidation. Vibrator placement in slipform mold must not touch steel. If steel vibrates, causes voids. Operator needs to watch for concrete build up on equipment hoppers. Equipment techniques and vibrator set-ups for slip form can achieve superior construction of parapet walls. Paving speed has a significant affect in consolidation. Paving speed must match the mix design. Ambient air temperatures and weather plays an important role in speed. Speed also depends on vibrator placement and reinforcement configurations. Steel must be rigid and not move. Dry runs should be conducted to make sure of proper clearances. Bridge Deck Cracks – Adding mist nozzles and attachments for finishing and pans. Drums are adjustable to handle different amounts and types of mixes. Vibrating methods – hydraulic stinger vibrators, pan type vibrators, drum vibrators, undercarriage vibrators. Vibrator technique depends on type and amounts of steel. VIBROPAC very effective. Cure needs to go on sooner than later. Before the curing is applied, the use of fog nozzles. Skewed areas at the decks should be protected due the length of time to finish the entire portion and the leading edge gets too dry. Q) Research on improved quality A) Conference in Ohio that were having problems. The mix they were using was problematic. Heavier weights used on vibrators fixed the some of the issues and is now standard. They will work with the contractor on proper placement. Also, contractor experience and training people is also a challenge. Q) Can you change vibrator heads. You can change vibrators but you will affect the amplitude and that could effect the consolidation. Q) Have you looked into putting speed monitors on pavers. A) Radar does not work at very low speeds. They will be hesitant in implementing this. Q) Anything on website for troubleshooting. A) May be something to look into.

Peter Taylor – Impact of Materials and Mix on Concrete Cracking Cracking 101 – Need to get cracks under control. Control size and places. Three Mechanisms – Chemical Shrinkage – Volume changes after hydration. Increases with decreasing w/c. Autogenous Shrinkage – adding water does not help. Capillaries – voids left behind which reduces strength, durability, and increase in shrinkage. Drying Shrinkage – The meniscus changes and effect shrinkate. Minimize dry shrinkage by minimizing paste (water) content. Minimize moisture loss to the system (evaporation retarders, curing compounds). Supply curing moisture and adjust timing of drying. Thermal Shrinkage – Concrete expands when heating and contracts when cooling. If it sets while hot – it has more shrinkage potential.

Thermal – 140 – 350 millionths starts with cooling Drying – 400 to 800 millionths starts with drying and continues for a long time.

Can you have thermal shrinkage before concrete sets? It is possible, but would need to see what the temperatures were before the initial sets.

Shrinkage is additive – Autogenous + Settlement +Plastic +Thermal +Drying=Total Shrinkage. These show up at different times, shows up with different cracking patterns.

Cracking – Stress = Restraint + shrinkage + stiffness. Restraint comes from end connections, friction, steel, etc. Stress depends on contraction, stiffness, creep. Cracking depends on stress and strength. Measuring Shrinkage and Cracking – ASTM C157 and C1581. ASTM C1581 results can be useful in pin pointing early stresses. Cracking depends on shrinkage, temperature, stiffness, strength and creep. Higher the stiffness the higher cracking potential. Try to prevent stiffness going up before strength. Cement – Drying shrinkage – increasing fineness, increasing C3A/sulfate, increasing alkali, increasing C3A. Unfortunately – this is where our early strength gain comes from. SCM – Temp. increase is generally lower (good), but strength gain is slow (bad). SCMs will not necessary help bridge deck cracking and it will all depend on other factors. Drying shrinkage is generally similar. Chemical admixtures – depends on chemical and can go either way. Increasing clay dramatically increases shrinkage** Coefficient of thermal expansion can effect cracking. Mix proportions – Drying = paste content, Thermal = paste content and CTE, Timing = cementitious material and interaction. Therfore, minimize paste content, well graded aggregate, watch bleeding, don’t go too low on w/c ratio, choose appropriate cementitious materials. Construction – Keep temps low, watch evaporation, consolidate, curing, provide enough joints, cut at right time. Reduce shrinkage – paste content, aggregate quality, binder type. Reduce restraint/stress – joints, saw cuts, detailing, strength, stiffness, creep. Change the timing – setting time, temperature, binder type. Prepare.

Place concrete when the concrete is cooler than the deck. 15 min break.

Long life pavement conference will fit in well and take the place of the MCC meeting. There will be more information at www.fhwa.dot.gov/pavement/concrete/2006conf.cfm. Rosemont Doubletree request rate - $144 + 13%. MCO meeting on October 24th. Long Life Pavement Conference – October 25th – October 27th, 2006. Check the MCC website for additional information.

Adapting HiperPave to Bridge Deck Construction – Jim Grove, PCC Tech Center. Inputing parameters into HiperPave to predict excessive stresses. Weatherdata can be downloaded to predict and monitor stress. Typical Uses – predict responses in cold and hot weather, predict potential strength ratios, changing mix design to accommodate weather changes. Factors contributing to bridge deck cracking. Design factors, materials, PCC properties, Construction practices. Preventive Measures – post tensioning of slab, and other design changes. Bridge Modeling of Thermal Stresses. Other Design Influences. Geometry, Use of concrete forms, air cells in box girders, bridge deck overlays. Restraint conditions. Bridge Deck Early-Age Cracking. Conclusions – Determines if night work necessary, effects of early opening to traffic induce more cracking in the PCC bridge deck, is high strength good. Where are we at – Spring 2005 – Didn’t see significant cracking. July 2005 – Presented it to Kansas, but needed to finish current pooled fund study. Today, Looking for a state that would consider being a lead state in a pooled fund study. Proposed Research – Transform HIPERPAV into HIPERBridge, Possible Research Team. John Staton mentioned that he would like to see something scientific on when to place a deck versus method specs on forcing all pours to be conducted at night. Illinois, Oklahoma, Ohio, North Dakota, Minnesota, Missouri, South Dakota, New York, Georgia, Wisconsin, Kansas, Indiana, Michigan are all in agreement that this would be a great tool in the tool box and are interested, however, all states will need to get approval for funding.

Precast Bridge Approaches and Semi Integral Bridge Abutments – Mike Laviolette, ISU Bridge Center Deteriorated bridge expansion joints and approach pavement. Issues: Unreinforced at the paving notch and abutement. Void left under the pavement that has no structural support. Problem Statement by FHWA to look at post tensioned pavement. Possible applications, Bridge approach pavement, ramp pavement, mainline widening under bridges, pavement. MoDOT precast pavements (2005) – Investigates the possibility of a precast pavement. IowaDOT precast approach pavement. 85 ft long section of pavement before/after a bridge. Inplementation/Tech Transfer plan for precast sections. Research continued for fast track applications. Investigated a new design for bridge deck abutments. Looking into Ultra-high performance concrete used at these locations. Drawback is that it is expensive. Lab testing conducted of the Precast paving notch with the UHPC. Very close in having the precast paving notch fully designed to handle traffic capacities. Future testing – ultimate strength. What holds the pavement on the notch. Probably come up with an anchoring system to hold the pavement in place. Move the open joint as far away from the bridge. Smooth face on smooth face in lab. Pull off test conducted to check bond.

CP Tech Center Activity Update – Dale Harrington absent – Jim Grove to give presentation. The PCC center in 2000 thru ICPA, ISU. The national center has started in 2005. Unity through a common goal. The center is research coordination through sharing of information. Facilitation others conducting research and help researchers access the right resources. Bring together partners, facilitate cooperation, partner with researchers across the country, provide tech transfer, and accelerate implementation. Operating Structure – Executive Board of Directors – Advisory Board. Concrete pavement research funds - $10M national center, $16.4M for research. CP Roadmap – 12 tracks, 250 problem statements, $250 M, 10 years. Coordinate to spend this the most effectively. The center does not owned or tied to funds. Administration of the Road Map, RFP currently on the street, Due April 21st, Supports the Executive committee, Supports the track leaders. Mix analysis, surface characteristics, concrete overlays, long life pavements. Mix Analysis on SCC for slip formed paving. Optimized surface characteristics – noise and texture. PCC Pavement Overlays.

Wrap-up – Thanks for Jim Pasoda and Matt Ross for supper and Jay Page for peanuts.

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