Presentation on theme: "By Richard Sampson & Dustin Lang"— Presentation transcript:
1 By Richard Sampson & Dustin Lang SLURRY SEAL PROJECTSBy Richard Sampson&Dustin Lang
2 WHAT IS A SLURRY SEAL?A Slurry Seal is a cold mixed asphalt. It consists of a graded aggregate, a binder, fines and additives. It is a hard wearing surfacing for pavement preservation.
3 WHAT IS A SLURRY SEAL MADE CONSIST OF Mixture of:Asphalt Emulsion (Approx. 14% by total aggregate)Water (Approx. 12% by total aggregate)Aggregate (Type I, II or III)CementAdditives
4 MAXIMUM ALLOWABLE THICKNESS OF SLURRY IS 1 ½ TIMES MAXIMUM ROCK SIZE
5 SLURRY SEAL LIFE EXPECTANCY 7 YEARS + LIFE SPANAND LONGER WHEN USED FOR A TRUE PREVENTIVE MAINTENANCE PROCEDURE
6 SLURRY SEAL IS USED FOR: Seal sound, oxidized pavementsRestore surface texture by providing a skid-resistant wearing surfaceImprove waterproofing characteristicsCorrect ravelingProvide a new surface where weight restrictions preclude the use of heavier overlaysAlternative to a seal coat
7 SLURRY SEAL SHOULD NOT BE USED TO: Correct surface profileFill potholesAlleviate cracking except for short-term weather protectionUsed on primarily new pavement
8 PROPERTIES - SLURRY SEAL Surface treatment of equal thicknessThickness is equal to the largest stone of the component aggregateMay be conventional or polymer modified aggregateCan be slow or quick settingUsually Cationic in nature
9 PROPERTIES-SLURRY SEAL 6. Slow set breaks by evaporationQuick set breaks emulsions maintain a degree of chemical breakBoth systems are dependant on environmental conditionsQuick set cures within an hourSlow set cures within a couple of hours
11 SUGGESTED APPLIATION RATE RATE OF APPLICATIONAGGREGATE TYPELOCATIONSUGGESTED APPLIATION RATETYPE IParking Areas, Airport Runways8-12 lb./sq. yd.TYPE IIGeneral Purpose, Urban & Residential Streets, Arterial Routes, Highways10-18 lb./sq. yd.TYPE IIIHigh Speed Roads, Industrial Estates15-22 lb./sq. yd.Above Data taken from International Slurry Surfacing Assn Workshop and Valley Slurry Seal website.
12 SLURRY SEAL VS. SEAL COAT Vehicle damage less likelyWider temperature placement rangeFewer personnel required for inspectionLess materials testingTraffic speeds can be raised much soonerLife of a slurry sealRequires less equipmentRequires a consistent plain from outside edge to inside edgeProject can be completed in a shorter durationGreater possibility for vehicle damageFaster initial seal operationRequires more equipment for placementTraffic speeds reduced for longer periodLife of a seal coatPlacement unaffected by sloughsSeal coats lose chipLess expensive than slurry seal
13 DIFFERENCES BETWEEN SLURRY SEAL AND MICROSURFACE Mixture of emulsified asphalt, fine aggreagate,mineral filler, and waterBest preventive maintenance for surfacesSeals surface, stops pavement raveling, & smoothes and waterproofsProvides non-skid surfaceCannot stack materialNon-structuralMICROSURFACEPolymer asphalt emulsion, selected Fine Grade Aggregate, mineral filler, & waterCan be placed at a thickness of up to 1.5” (multiple layering is possible)Used for rut fillingProvides non-skid surfaceStructural overlay
14 2006 SLURRY SEAL VS. SEALCOAT COSTS GRAND FORKS SEALCOAT PROJ. PRICESAverage price HFMS $ GalAverage Price CL $22.85 TonPrice CRS-2P $ GalPrice CL $30.00 TonGRAND FORKS SLURRY SEAL PROJ. PRICESAsphalt Emulsion for Slurry Seal $ GalAgg. For Slurry Seal-Type II $67.00 Ton
15 SLURRY SEAL VS. SEAL COAT COST COMPARISON PER MILE GRAND FORKS SEAL & COAT PROJ. PRICESAverage price HFMS $ 5,801Average Price CL $ 4,022$ 9,823Price CRS-2P $ 7,885Price CL $ 5,280$13,165GRAND FORKS SLURRY SEAL PROJ. PRICESAgg. For Slurry Seal-Type II $ 9,827Asphalt Emulsion for Slurry Seal $ 6,333$16,160Quantities computed using 24’ widths and no shoulders
16 SLURRY SEAL COVERED UNDER SPECIAL PROVISION SP471(02)
17 SPECIAL PROVISION Borrowed heavily from Nevada Issues addressed in SP: Materials, Engineering, Equipment, Weather Limitations, Traffic Control, Surface Preparation, Application, Measurement
18 SPECIAL PROVISION-AASHTO SPECIFICATION COVERAGE Additives1. ISSA TB-139Emulsified Asphalt1. AASHTO T592. AASHTO T49Aggregates1. AASHTO T11 & T272. AASHTO T2Deleterious Substances1. AASHTO 176Soundness1. AASHTO T104Hardness1. AASHTO T96Moisture on weight of aggregate1. AASHTO T19
19 REQUIRED TESTS AND MIX DESIGN SPECIFICATIONS AS PER SP 471(02) ISSA TESTDESCRIPTIONSPECIFICATIONNO.ISSA TB-106Slurry Seal Consistency3 cm MaximumISSAWet 30 Minutes (Set)12 kg-cm Minimum77 degrees F.West cohesion at 60 Minutes20kg-cm MinimumISSA TB-109Excess Asphalt by LWT Sand Adhesion50 g/sq. ft. MaximumISSA TB-114Wet StrippingPass (90% Minimum)ISSA TB-100Wet-Track Abrasion Loss, One-hour Soak75 g/sq.ft.ISSA TB-113Mix Time*Controllable to 180Seconds Minimum*The mixing test and set-time should be performed at the highest temperatures expected during construction.
20 COMPONENT MATERIALS-SP 471(02) Residual Asphalt8.0% to 13.5% by dry weight of aggregateMineral Filler0.5% to 2.0% by dry weight of aggregateField Control AdditiveAs required to provide the specified propertiesand meet the wet cohesion requirementsWaterAs required to provide consistency
21 EMULSIONS CSS-1h CQS-1h emulsion used QS-1h SS-1h EMULSION SPECIFICATIONS ARE FORMULATED FOR CAPITIBILITY WITH THE AGGREGATE AND MEET MIX DESIGN PARAMETERS
22 SPECIAL PROVISION-AGGREGATES Aggregate will be accepted at the job location or stockpile based on the passing average of 5 gradation testsDeleterious substancesSoundnessHardness
23 AGGREGATES CHARACTORISTICS Geology-Compatibility, adhesion, and cohesiveness are affectedShape-Slurry aggregates must have fractured faces in order to form the required interlocking matrix (rounded aggregates result in poor mix strength)Texture:Rough surfaces bonds better with emulsions
24 AGGREGATES CHARACTORISTICS-CONTINUED Age & Reactivity-Aggregates the are crushed recently have a higher surface charge than weathered aggregatesClean Materials-Clay, dust, and silt can cause poor cohesion
25 REASONS FOR FAILURE General wear Surface oxidation Abrasion under trafficSurface deflectionCracked surfacesBase or subgrade failureDelamination
26 TEST SAMPLE DEPICTIING TOO MUCH MINERAL ADDITIVE Segregation of aggregatesExcessive moisture around edges of sampleSample will be very slow setting and may have to be removed from roadwaySegregation of aggregates
27 EXAMPLE OF AN ACCEPTABLE SLURRY SAMPLE Uniform aggregate throughout sampleMinimal water puddling outside of sample
32 PROJECTS: SNH-6-081(063)163 U.S. 81 FROM MANVEL TO LEVANT & SNH-6-081(062)175 U.S. 81 FROM ARDOCH TO MINTO
33 PROJECTS SCOPE OF WORK Slurry Seal both lanes using Type II aggregate for slurry and CQS-1H oilSlurry Seal U.S. 81 Manvel IntersectionPrior to Slurry Seal, tack lanes using CSS1HSeal shoulders with CSS1HSeal and apply Class 44 Blotter to approachesPre-install Plastic pavement marking Message for 2 R/R crossings & Stop bar at Manvel IntersectionEpoxy Permanent Pavement Marking
34 MIX DESIGN BEFORE WORK BEGINS: A contractor submitted mix design covering the specific material to be used on the projectA qualified laboratory shall present certified test results for the contractor’s approval.No substitution of materials will be permitted unless first tested and approved by the laboratory preparing the mix design.
35 N.D.D.O.T. SLURRY SEAL SPECIAL PROVISION 471(02) GRADATION REQUIREMENTS STOCKPILESIEVE SIZETYPE II-% PASSINGTOLERANCE3/8"100+-7%#490-100#865-90#1645-70#3030-50#5018-30+-6%#10010-21+-4%#2005-15-0.03Aggregate is accepted at job location or stockpile. The stockpile shall be accepted based on 5 gradation tests according to AASHTO-T2After the mix design gradation is submitted, each sieve shall not very by more than the stockpile tolerance and still remain within the gradation band.
36 ACTUAL TARGET TEST RESULTS SNH-6-081(063)163 & SNH-6-081(062)175TYPE II-% PASSING10090-10065-9045-7030-5018-3010-215-15DESIGN VALUES (MIX DES. RESULTS)90.571.757.338.922.910.95STOCKPILE TOLERANCE90-9765-7950-6432-4618-2910-155-8SIEVE SIZE3/8"#4#8#16#30#50#100#200SAMPLE A9374523622126.6SAMPLE B9478574024SAMPLE C95765539137SAMPLE D77567.1SAMPLE E41256.8OVER/UNDER TARGETTargets taken from lab results
38 ROADWAY PREPARATION REPAIR CRACKS BEFORE SEALING All cracks should be sealed and sealant allowed to cureMost cracks will reappear
39 POOR CRACK REPAIRCracks and subgrade problems should be properly repaired and ample time to cure prior to placement of slurry seal
40 ROADWAY PREPARATIONCracks 1/4 “ or greater should be filled with crack sealing material and be allowed to cure prior to slurry placementCrack sealant that has not cured or that has been tacked may stick to tires on the slurry paver
41 ROADWAY PREPARATIONSlurry Seals are not designed to fix this
42 ROADWAY PREPARATION-MUST BE MADE WITH TIME FOR CURE BEFORE SEALING Rutting must be repaired prior to slurry seal.Pavement leaching oil will cause the slurry seal to lift.
43 ROADWAY PREPARATION Remove all organic materials from roadway Grind any existing plastic pavement marking to be slurry sealed overRepair roadway asphalt problems due to subgradeSeal all cracks and allow for cure timeAsphalt patches with excessive oil can bleed threw slurryHigh pressure wash or grind oil spotsEnsure construction equipment does not have oil or hydraulic leaksBroom ahead of slurry sealingMark and cover all manholes, gate valve covers, curb inlets as neededMark stop bars and messages to be reinstalled
44 CALIBRATION Calibration of the aggregate using loader scale Receive a copy ofthe CALIBRATIONSUMMARYIf same materials are being used for multiple jobs, new calibration is not necessaryISSA requires minimum of recalibration every 6 monthsSpecial provision allows engineer to request calibration at anytimeCALIBRATION
48 ROADWAY PREPARATIONSpecial Provision-Tack Coat, if required shall be applied with 3 parts water with a distributor at a rate of 0.10 – 0.15 gallons per square yard. This equals to gallons of tack only per yard.U.S. 81 worked best with minimum coverage
49 WEATHER CONCERNSMedium to heavy rain can wash slurry seal oil from roadwayCan cause aggregate separationMay require total removal of damaged slurry sealTakes a minimum of an hour (plus) to be cured adequately
51 PREFORMED PATTERNED PAVEMENT MARKING-MESSAGE Not recommendedSpreader bar skids will cut into message if run overStickiness of the tack coat can lift the temporary paper liner covering message, allowing slurry to cover and stain message
58 CONTROL LINEMissed matching slurry at centerline due to bad control lineGood centerline control will prevent such problems to include consistent slurry seal lane widths and a cosmetically pleasing job.
59 PERIODIC MAINTENANCE/CLEANING IS NECESSARY THROUGHOUT DAY
61 SLURRY SEAL PLACEMENT PROBLEMS If the outside skid gets too close to the rounded edge of existing pavement, the slurry box may slide and cause the box to vibrate or jump. This can cause a washboarding effect on the slurry surfacing.
62 EDGE LINEA good control line will aide in a smooth and straight edge line.Notice slurry material is leaking between the primary screed allowing the slurry to cover beyond the skids
67 COMING OFF A BRIDGE DECK Use of roofing paper and duct tape to cover edge of bridge deck
68 TRAFFIC CONTROLUsually, within an hour, the slurry can carry traffic but not excessive twisting/turning of heavy equipment
69 EPOXY PAVEMENT MARKING Moisture in slurry can continue to leach long after placement, causing damage to permanent pavement marking. A minimum of four weeks between slurry placement and permanent pavement marking placement is recommended.Epoxy pavement marking was placed about 3 weeks after completion of slurry seal.
74 ADDITIONAL INFORMATION-ITEMS TO MONITOR Ensure calibration is completed before placement of slurry seal or calibration data is provided from previous project (using same materials)Ensure inappropriate materials do not contaminate slurry from digging too low in stockpileMonitor stockpile segregationIs moisture in stockpile consistent (a new mix design may be necessary if moisture changes dramatically
75 ADDITIONAL INFORMATION-ITEM TO MONITOR Recommend, as a minimum, calculating aggregate cut off at end of each day (the difference between the slurry machine’s dial reading calculation and total tonnage hauled by totaling tickets for comparison)Monitor air and surface temperatures for limits as specified in the special provisionMonitor weatherMonitor roadway ahead for last minute contaminationTake periodic depth checks of placed slurry seal make sure to stay within thickness spec.Check yield on a regular basisMonitor slurry for minimal drag marks, should to exceed 6”Ensure the centerline overlap does not create a safety hazard due to buildup of slurry on edge
76 ADDITIONAL INFORMATION-ITEMS TO MONITOR Adjust squeegee (secondary strike-off) angle for best or preferred surface textureEnsure traffic control is maintained and minimal delays to the publicMonitor construction equipment for leaking fluidsAcquire samples of materials, as requiredWatch for slurry not overlapping at centerlinePeriodic measurement of slurry seal widths
77 ADDITIONAL INFORMATION-ITEMS TO MONITOR Watch for washboard effect in the placed slurry sealKeep material haulers from driving on fresh tackWatch for leaking equipmentOver filled cracks can create problems-skids can hook material and drag it. Small pieces can than cause dragging problems when placing the slurry
78 EXAMPLE OF EXCEL SPREADSHEET YIELD CHECK DATE AUG TIME 17:13BEGENDRATELBSTONSOILOIL USEDOIL WTGAL USDREVDIFFON DIALUSEDBY DIALPER GAL1390035.714963692485695008.53BEGENDYIELDSTATIONDIFFWIDTHSQ YDSBY DIAL32564154051715912.520.83Green are required inputs and yellow shows desired information
79 TICKET WEIGHT COMPARED TO PLAN YIELD CHECK USING EXCEL SPREADSHEET SLURRY SEAL DIALS COMPARED TO TICKET TONNAGETYPE IITONNAGEAGG.OIL CUMPUTED FROMFROMYIELD BYPLAN RATEOVER RUNACTUAL TONS COMPAREDTICKETSTICKET20.86 PLAN YIELDUNDER RUNTO DIAL250.1520.99248.57
81 SLURRY SEAL PLACEMENT DAY 1-MANVEL INTERSECTION Slurry seal is basically placed in straight lines, overlapping. It is difficult to turn the slurry seal machine sharp enough to turn most intersections
82 SLURRY SEAL PLACEMENT DAY 2-MANVEL INTERSECTION
83 USE OF SPOTTING TABSSpotting tabs, if used for centerline control, can create a void as the tab is knocked down by the slurry boxThe tab can be torn away by the slurry box skid or the squeegeesAre used for marking utility holes, stop bars, inlets, etc.
84 EXAMPLE OF FIELD EXPEDIANT SLURRY SEAL FOOT WEAR
85 USEFUL WEBSITES Valley Slurry Seal Co International Slurry Surfacing AssociationMNDOTIntermountain Slurry
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