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SEALCOATING PRINCIPLES for CONTRACTORS PROTECTION & PRESERVATION OF ASPHALT SURFACES part i-general PRESENTED BY Girish C. Dubey President, STAR, INC.

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Presentation on theme: "SEALCOATING PRINCIPLES for CONTRACTORS PROTECTION & PRESERVATION OF ASPHALT SURFACES part i-general PRESENTED BY Girish C. Dubey President, STAR, INC."— Presentation transcript:

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2 SEALCOATING PRINCIPLES for CONTRACTORS PROTECTION & PRESERVATION OF ASPHALT SURFACES part i-general PRESENTED BY Girish C. Dubey President, STAR, INC. 1

3 OBJECTIVES 1. To understand Asphalt Pavements, their; a. Basic construction and make up, b. Strengths and weaknesses, c. Why they have to be protected ? d. Which types of pavements can be protected? e. How can they be protected ? Concept of SEALCOATINGS 2.Overall Savings and value to the property owner. 2

4 OBJECTIVES 3. Sealcoating Materials: a. Refined Tar Based sealcoatings (RTS) b. Asphalt Emulsion Based sealcoatings (AE). 4. Sealcoating Application: a. Equipment b. Mix Design compositions c. Application details and Cautions 5.Drying and cure of sealcoatings 6. Good Sealcoating Practices 7. Do and Don’ts. 8.Trouble-shooting 9.Commonly asked questions. 3

5 ROAD CONSTRUCTION A. PRIOR HISTORY OF ROAD CONSTRUCTION: Constructed with Clay, Limestone, Rocks- Functional but severely damaged by rain: The aggregates absorbed water, became soft and lost their strength to support loads. Roads were destroyed in no time. B. ASPHALT AS A PAVING MATERIAL- Used since 18th. century A by-product of petroleum refining process was plentiful and had excellent;  Adhesive (Gluing) properties,  Water Proofing (repellency) will not let water penetrate the pavement and damage it.  Flexibility- Pavement surface will flex under traffic without cracking. ASPHALT KEPT WATER OUT OF THE PAVEMENTS, KEEPING THE BASE DRY AND FUNCTIONAL 4

6 WHAT IS ASPHALT IT IS A BY-PRODUCT OF PETROLEUM REFINING PROCESS. CRUDE PETROLEUM - ORIGINATED FROM THE DECAY OF MARINE LIFE OVER MILLIONS OF YEARS. CRUDE PETROLEUM REFINIG PROCESS REMOVE LIGHTER FRACTIONS: SOLVENTS, GREASE, OIL…. RESIDUE: ASPHALT ASPHALT IS A VERY COMPLEX MIXTURE OF OVER 5000 COMPOUNDS. WHAT IS ASPHALT ? 5

7 ASPHALT PAVEMENTS WHAT THEY ARE AND HOW ARE THEY CONSTRUCTED ? Pavements are t he solid floor of any construction that carries traffic;  VEHICULAR : High Traffic :Highways, Roads, Streets, Low traffic : Airport runways, aprons, parking lots, driveways, service stations..  PEDESTRIAN: Walkways, Play Grounds, Schools, etc. CONSTRUCTION The earth is removed and - Filled with large aggregates (gravel, rocks, limestone- Base course - Filled with smaller aggregates- Sub-base course - Covered with hot molten asphalt (5-10% By weight) mixed with finer aggregates- top course. THIS TOP LAYER, SO TO SPEAK, IS THE " ROOF OF THE PAVEMENT". TOP COURSE, Asphalt Hot-Mix. SUB-BASE COURSE BASE COURSE THE CONSTRUCTION VARIES WITH THE TRAFFIC LOAD REQUIREMENTS. 6

8 ASPHALT AS A PAVING MATERIAL SHORTCOMINGS 1. DETERIORATES UNDER SUN'S ULTRAVIOLET RAYS Unstable (aliphatic) compound in asphalt breakdown. 2. Attacked or Dissolved by: a. DISSOLVED BY PETRO-CHEMICALS: GASOLINE, OILS, FATS, GREASE ETC.  Same origin-crude petroleum.  Natural Affinity-Co-exited in nature over mils. Of yrs.  Like dissolves like. b. DEICING SALTS- Attack unstable compound in asphalt c. WATER- Strips asphalt form aggregates. 7

9 HOW ASPHALT BREAKS DOWN The top layer degrades from the elements soon after the asphalt installation. Surface cracks develop, Asphalt becomes brittle, water seeps in, and cracks widen, damaging the base Surface cracks develop, Asphalt becomes brittle, water seeps in, and cracks widen, damaging the base. Trapped water weakens the foundation and further damage occurs under traffic and seasonal freeze / thaw cycles. Further asphalt damage is done over time. Chunks of asphalt begin to break away and potholes quickly develop. End of The Pavement 8

10 HOW TO PROTECT ASPHALT PAVEMENTS : - APPLY A COATING ON THE ASPHALT SURFACE THAT WILL: FORM A BARRIER COAT TO SHIELD THE ASPHALT PAVMENT FROM THE ELEMENTS THAT DESTROY ASPHALT SUN’S UV RAYS, GAS, OIL,FAT AND PETROCHEMICALS, WATER AND DE-ICING SALTS ULTRAVOILT (UV) RADIATIONS SOLVENTS WATER & DE-ICING SALTS FUEL, OIL & FATS SEALCOATING ASPHALT PROPERTIE STAY "SEALED IN“. SEALS IN THE EXCELLENT PROPERTIES OF ASPHALT 9

11 REGULAR MAINTENANCE PROGRAMS: 1. SAVES MONEY FOR THE OWNER; PAVEMENT LIFE CAN BE EXTENDED BY OVER 300% 2. PROTECTS AND PRESERVES THE ASPHALT PAVEMENT. 3. BEAUTIFIES THE PAVEMENT & ENHANCES THE BUISNESS IMAGE. 4. CLEANING BECOMES EASIER; RAIN WASHES OFF THE DIRT AND DEBRIS EASILY TRAFFIC MARKINGS LAST LONGER. 10

12 Pavement Preservation Program Cost-Benefits Analysis 11

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15 DO ALL PAVEMENTS NEED SEALCOATING ? MAY NOT BE NEEDED HIGH TRAFFIC BEARING PAVEMENTS HIGHWAYS, ROADS, STREETS THE ADVANTAGE- The kneading action of the traffic. Brings up fresh asphalt to the surface. The breakdown is not localized. DESPERATELY NEEDED LOW TRAFFIC, NON-TRAFFIC BEARING PAVEMENTS: Lack of the kneading action of traffic. DrivewaysFast food Parking LotsShopping Malls Gas StationsSchools…………. 14

16 SEALCOATINGS ARE WATER-BASED COATINGS, MADE BY DISPERSING: (Batch or Mill process) 1. Refined Tar (RTS) or Asphalt (AE) 2. Water 3. Clays and 4. Surfactants, Emulsifiers, Polymers. 15

17 WHY WATER-BASED? 1. SAFE TO HANDLE AND STORE. 2. NON-FLAMMABLE 3. EASE OF WATER CLEAN UP OF TOOLS, 4. NO SOLVENT FUMES OR HAZARDS OF SOLVENT 5. EASY TO APPLY WITH BRUSH, SQUEEGEE APPLICABLE SPECIFICATIONS ASTM, , U.S. FEDERAL AVIATION ADMINISTRATION (FAA SPECS.) ASPHALT SEALCOATING MANUFACTURERS ASSOCIATION (ASMA) COMMERCIAL SPECIFICATIONS

18 Now you know WHAT SEALCOATINGS DO? 1.Protect the Asphalt pavements from: Sealcoats form a barrier coat to shield asphalt pavements from The damaging elements;  Breakdown under sun’s UV radiation,  Oxidation,  De-icing salts and water  Gasoline, oil, fats, etc.,  Petrochemicals, anti-freeze, etc. 2.Extends the life of the pavement by avg. 3 times. Seals the asphaltic oils in the pavement and keeps them functional (flexible) for a long time. 3. Reduces overall up maintenance cost of the pavement. 4.Improves the curb appeal. 5. Adds to the over-all value of the property. 17

19 DO NOT OVERSELL SEALCOATINGS!! 1. Sealcoatings are not designed to repair the pavement defects  Cracks, surface or structural.  Alligatored cracks.  Lose chunks of asphalt,  Deteriorating shoulders. 2.Do not over-promise, sealcoating will make the pavement look like new. 3.Do not sealcoat over  Gravel or dirt roads  Wood  Gilsonite coated pavements 18

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21 SEALCOATING PRINCIPLES for CONTRACTORS PROTECTION & PRESERVATION OF ASPHALT SURFACES part iI- APPLICATION PRESENTED BY Girish C. Dubey President, STAR, INC. 20

22 SEALCOATING APPLICATION Sequence, Steps, Procedure & Precautions SEQUENCE  MEASURE, CALCUALTE, COST MATERIAL, O/H, % PROFITS.  BID COMPETITIVELY. RECALCUALTE  DEVELOP LOGISTICS-CREW, TOOLS, SUPPLIES.  MOBILIZE –PERSONNEL, MATERIALS, EQUIPMENT. PAVEMENT PREPARATION- TRIMMING, CLEANING, REAIRS, ETC. SEALCOATING APPLICATION BLOCK OFF SEALED AREAS, OPEN AS AGREED  DEMOBILIZE-EQUIPMENT. LEAVE A SIGN. NO TRASH NO DEBRIS  COLLECT PAYMENT AS AGREED. 21

23 22 MATERIALS  SEALCOATINGS : Good Quality, Must Meet Applicable Specifications.  WATER: Clean, Potable.  SAND: Clean, Quarts, Angular, Mesh  ADDITIVES: As Recommended.

24 INSTRUCTIONS FROM SEALER SUPPLIER. DETAILS ON; MIX DESIGN- Proportions of Sealer, Water, Sand and Additives.  PAVEMENT PREPARATION- Cleaning, Spot Priming, Patching and Crack filling, Patching.  APPLICATION RATES- Coverage Rates.  PRECAUTIONS- Application, Handling and Storage. Must read MSDS 23

25 SEALCOATING MIX DESIGN SEALER IS GENERALLY SUPPLIED AS A CONCENTRATE. Prior to application, It is mixed with: Water Sand/Aggregate Additive In specified proportions. That is called a Mix Design, The quantities are denoted as % of Undiluted Sealer, With sealer being 100%. Manufacturers recommend a specific mix design for a given job. 24

26 1. Water Achieves proper fluidity Expressed as % of sealer Clean, Potable and Free of salt 2. Sand/Aggregates Adds traction & appearance, Fills minor surface cracks Expressed as lbs./Gallon of sealer Must meet specs. 3. Additives Fast/Uniform drying Sand suspension and anchoring Improves chemical and UV resistance Expressed as % of sealer 25

27  Sealer (RTS)100 Gals.  Water (25-30% dilution) gals.  Sand (2-3 lbs./gal) lb.  Additive (2-5%)2-5 gal. Sealer is always used as the 100 Quantities of other materials are Calculated using 100 Mixing has to be thorough. Hand Mixing may not be enough. Improper mixing –Poor Performance. 26

28 FOLLOW THE MANUFACTURERS’S INSTRUCTIONS Water a.Too much- Will reduce the dry film thickness- Poor performance. b.Too little- Poor flow of the mix, too much sealer may cause tracking- waste of money Sand/Aggregates a.Too much (over 5 lb./gal) – Reduced flexibility, may cause pre- mature surface cracks. Excessive amount-may cause peeling. b.Too little or none- Uneven appearance, may affect slipperiness Additives a.Too much (over recommended amount)- May destabilize the sealer mix. Waste of money. b.Too little- May be ineffective for the intended purpose. 27

29 COVERAGE RATES Definition ~ Expressed in 2 ways 1. Gallons of conc. Sealer needed cover One (1) sq. yard. 2.Square feet covered by One (1) gal of conc. Sealer. Commonly Expressed as Gallon/sq. Yard. Standard Coverage Rates Commonly calculated for two (2) coats of sealer 1 st Coat gal. conc. Sealer/sq. yd. 2 nd Coat, gal. conc. sealer/sq. yd. T Total of two (2) coats = gal. Of conc. Sealer /sq. yd. 28

30 JOB CALCULATIONS 1. Calculate the area Assume 10,000 sq. yd. 2.Calculate total undiluted sealer 0.18 to 0.20 gals. Per sq. yd Application/Conc. Sealer Coverage rate Rate Gal/Sq. Yd Total Sq. yards Total Conc. Gals. 1 st. Coat nd. Coat Total for 2 coat

31 JOB CALCULATIONS Mixture From Conc. Sealer ApplicationMix DesignTotalMixed Sealer Conc. 30%Sand, 3lb.MixtureFactor Gal Lbs. (Gal)Gals.MSF 1 st. Coat (166) nd. Coat (111) Total for 2 coat (277) Mixed Sealer Factor (MSF) Ratio between mixture and the conc. Sealer Conc. Coverage Rates Shall be multiplied with MSF 30

32 SEALCOATING APPLICATION Sequence, Steps, Procedure & Precautions STEPS IN APPLICATION 1. PAVEMENT PREPARATION 1.1. CLEANREMOVE GRASS, WEEDS, AND DIRT USING BRUSH, BROOM, BLOWER, POWER WASHING. 1.2 REPAIR CRACK FILL WITH: - COLD POUR FOR CRACKS UPTO ½ INCH WIDE - HOT POUR CRACK FILLER FOR LARGER CRACKS. PATCH & OVERLAY THE PROBLEM AREA- BADLY ALLIGATORED, BASE PROBLEMS. ALLOW THE FRESH ASPAHLT TO CURE. 1.2 OIL SPOTSSCRAPE HEAVY BUILD UPS. WASH WITH DETERGENT, AND SEAL WITH OIL SPOT PROMERS. SOFT AREAS-PATCH. Sealcoating will not fix the pavement problems. Pavement must be sound, free of defects prior to sealcoating. SEALCOATINGS ARE SURFACE PROTECTIVE TREATMENTS, NOT REPAIR PRODUCTS. 31

33 SEALCOATING APPLICATION Sequence, Steps, Procedure & Precautions STEPS IN APPLICATION 2. SEALCOATING APPLICATION 2.1. MATERIAL PREPARATION FOR THE JOB:  USE SUGEGSTED MATERAILS AND MIX DESIGN FOR THE JOB.  HAVE THE RIGHT MIXING EQUIPMENT WITH MECHANICAL AGITATION  KEEP MATERIAL AGIATETD DUING APPLICATION  MAKE SURE THAT SAND STAYS IN SUSPENSION.  MAKE SURE APPLICATION EQUIPMENT (PUMPS, NOZZLES, TIPS, WAND, ETC. ARE IN GOOD WORKING CONDITION. 32

34 SEALCOATING APPLICATION Sequence, Steps, Procedure & Precautions STEPS IN APPLICATION 2. SEALCOATING APPLICATION 2.2. APPLICATION  TRIM THE EDGES WITH A SQUEEGEE OR A BRUSH  APPLY THE SEALER ON A SAMLL PRE-MEASURED AREA TO SET CORRECT APPLICATION RATE.  APPLY THE SEALER IN LARGER AREAS USING A SUITABLE METHOD- SPRAY, BURSH OR SQUEEGEE. KEEP MATERIAL AGIATETD DUING APPLICATION  MAKE SURE THAT SAND STAYS IN SUSPENSION.  APPLY THE NO. OF REQUREID NUMBER OF COATS  IN MULTIPLE COAT APPLICATION-ALLOW EACH COAT TO DRY SIFFICIENTLY BEFORE APPLYING THE FOLLOWING COAT  ALLOW TO THE FINAL COAT TO DRY FOR A MIN.OF 24 HRS., BEFORE OPENIG THE LOT FOR TRAIIFC. 33

35 SEALER APPLICATION MEHODS BRUSH SQUEEGEE OR SPRAY??? Comparison aspectsSPRAYSQUEEGEE InvestmentConsiderableEconomical to considerable. Cost Controls. Material usage. Controllable, Better Control of Material Usage Un-controllable, material usage will depend upon the surface roughness and age. Skill LevelHighly Skilled work. Thorough training required Moderate skill. Not much training is needed. Size of ProjectsMedium to largeSmall, medium, large Appearance of the finished job Excellent, Uniform Textured appearance. Fair-to good, May appear streaky Safety in handlingGood, Material is under pressure, may accidently discharge due to equipment malfunction. V. Safe Application under windy conditions Risky- Stay away from buildings. No problem 34

36 SEALER APPLICATION MEHODS BRUSH SQUEEGEE OR SPRAY??? Comparison aspectsSPRAYSQUEEGEE InvestmentConsiderableEconomical Uniformity of the coating application Uniform on the surface as well as in the profile of the pavement. Thick in the profile and wipes the top of the aggregates in the pavement. ConclusionsMechanical application for both types are well accepted and have yielded years of dependable performance. le The main drawback is the cost control of the material usage Best compromiseBrush application of the first coat and spray application of the second coat. 35

37 SEALCOATING PRINCIPLES for CONTRACTORS PROTECTION & PRESERVATION OF ASPHALT SURFACES part iII-special notes (Do & DON’TS, TROUBLESHOOTING) PRESENTED BY Girish C. Dubey President, STAR, INC. 36

38 SEALCOATINGS- DO & DON’Ts DODO NOT General 1. Sell for intended purposeOversell. Sealcoating will not repair deteriorated pavements. 2. Follow manufactures recommendations for Application, safety in handling, compliance to regulations, and personal safety. FLY BY THE SEAT OF YOUR PANTS. -Ignore instructions and safety instructions. -Indulge in reckless practices. Inspection & Bidding Walk through, Measure, Pavement Prep steps. Calculate, Material, Labor, overheads (direct and general), profits. Depend on sketches, GPS maps, Property owners estimates and cost calculation for previous jobs. 37

39 SEALCOATINGS- DO & DON’Ts DODO NOT Technical Details 1.Sealer shall meet appl. Specs. 2.Mix design- Follow recommendations a. Water- clean and potable b. Sand-Clean, Quartz mesh. c. Additives- As recommended. 3. Mixing shall be thorough 1.Miscalculate the mix design. Sealer is 100 base. a. Sand- no used foundry or sand blasting spent sand b. Mix additives from diff. suppliers. Always seek sealer suppliers approval. 2. Incomplete/improper mixing shall result in poor performance. 38

40 SEALCOATINGS- DO & DON’Ts DODO NOT APPLICATION Follow manufacturers recommendation for ; a.Pavement preparation. b.Selection of application tools, brush, squeegee, spray, etc. c.No. of coats and coverage rates. d.Ambient application conditions and drying times a. Take Short cuts in pavement preparation. b. Over or under apply. c. Open the lot too soon. Have a disclaimer signed by the property owner if they want the lot opened sooner. d. Let the wash water go into storm sewer. e. Do not apply if there is any chance that rain will wash away the sealer into the bodies of water. Do a professional Job. Be a professional Leave dirt and debris, etc. on the job after finishing. DO NOT SHORTCHANGE YOUR CUSTOMER 39

41 TROUBLE SHOOTING Problems, Causes & Remedies ProblemsCausesRemedies  Pre-mature wear,  Un-even wear,  Sand knocked off 1.Thin coat application 2.Too much water in the mix. 3.Too much sand and large size, sand roll out that will abrade the sealcoating. 4.Inadequate mixing of components in the sealer 5.Improper cure conditions, too cold or freezing overnight temps. Get weather report for analysis. 6.Dirty, over-oxidized pavement. 7.Inadequate drying and cure, job was rushed and lot opened too soon. 8.Inferior Product-Quality Issues. 1. Right coverage rate 2.Right Mix design 3.Mix thoroughly. 4. Prepare the pavement right. 5. Do not apply under cold, high humid or foggy conditions. 5. Select the right products. Ask for performance reports from your manufacturer. 40

42 TROUBLE SHOOTING Problems, Causes & Remedies ProblemsCausesRemedies Un-even color & appearance problems 1.Cure under improper ambient conditions. 2.Curing under sun and shade. 3.Inadequate mixing of the components in the mix design. 4.Changing mix designs for the same project. 5.No or very little sand in the mix. Also sand un- evenly suspended in the mix. 6.Streaky appearance- sand falling in the windrows. Poor sand suspension in the mix. 7.Uneven rate of application, machine mal- function or in-experienced applicator. 8.Inconsistent pavement condition (smooth, rough, patchy, oxidized) 9.Changing direction of application, uneven brush or squeegee patterns. 10.Landscape irrigation run off. 1.Must apply under the right cure conditions. 2. Allow more cure time, the color will blend in. 3. Use the same mix design for the entire project. 4. Check the accuracy of the appl. Rate on a test area. 5.Follow uniform windrows. 6.Make property owner aware about inconsistent pavement. 41

43 TROUBLE SHOOTING Problems, Causes & Remedies ProblemsCausesRemedies Adhesion failure 1. Pavement not sufficiently cured (surface oily). 2. Pavement too old and oxidized, not properly cleaned and primed 3. Oil Spots not properly primed. 4. Dirty pavement Excessive oil, grease, etc. 5. Polished aggregates 6. Excessive sand loads (>8lb./gal) 7. Applied under cold or o/n freezing conditions. 1. Test the pavement to make sure the pavement is aged (cured enough) 2. Clean and prime with oil spot sealer or specialty coatings. 3. cure conditions must be right. 42

44 SEALCOATING PRINCIPLES for CONTRACTORS PROTECTION & PRESERVATION OF ASPHALT SURFACES part Iv- FREQUENTLY ASKED QUESTIONS PRESENTED BY Girish C. Dubey President, STAR, INC. 43

45 FREQUENTLY ASKED QUESTIONS: Sealer Performance Q.1.Why are two (2) thin coats better than one thick coat? A.1. Sealer applied in two coats dries and cures much better than one thick coat application. Remember sealers are water-based coatings, which cure through the process of water release (evaporation). A thin coat will release water much faster than a thick coat. If applied in one thick coat, sealer will have a tendency to hold water and stay soft for a longer period of time, possibly causing tracking. Q.2. Why did the sealer fail or peel? A.2. Peeling is caused by sealer not bonding to oil spots or any other surface contaminants like dirt, grease, etc. or oxidized pavements. All the areas shall be thoroughly cleaned; oil spots shall be primed with specialty primers. Oxidized pavements shall be treated with a diluted coat of sealer or a specialty coating or a diluted asphalt emulsion. Q.3. What causes white streaks in the sealer? A.3. Streaks in the cured sealer film are possibly caused by incomplete mixing of clays and fillers in the manufacturing process of the sealer. The Sealcoating manufacturer should be able to rectify this problem. 44

46  F REQUENTLY ASKED QUESTIONS: Q.4. Why does the sealer dry gray? A.4. Due to less than ideal conditions: High Humidity, Cooler temperatures, Shade. Mostly it is temporary, it will cure to a darker color. Remedy- Use of fast drying additives- helps sealer dry faster and at a uniform rate. Q.5. Why does the sealer wear out faster in traffic lanes, entrances and exits? A.5. More traffic More Wear. Excessive wear- Indication of adhesion problem to smooth/polished aggregates. Such Remedy- Use of specialty primers to penetrate the smooth polished aggregates and allow the sealcoating to bond, effectively. Prime faster traffic lanes, exits and entrances. 45

47 FREQUENTLY ASKED QUESTIONS APPLICATION Q.6. How soon I can sealcoat a freshly laid asphalt pavement? A.6. As soon as the surface rids of light oils through oxidation. Allow 90 days or more, depending upon locations. Perform a simple test called "water break test". - Spread some water on the surface. If the water sheets out without beading, you are ready to sealcoat. Remedy- For fresh patches, etc. prime with a specialty primer. Q.7. While spraying how do I know if I am applying at the recommended coverage rate e.g gallon/sq. yard? A Select 10’ x 10’ area of the pavement and place a 3"x 6" metal plate in the center. 2. Spray Sealcoating in this area. 3. Lift the metal plate before the Sealcoating dries. 4. Use the film thickness gauge to determine the wet film thickness. The reading will be in mils (1/1000 of an inch). Compare this reading with the desired film thickness for 0.12 gallon/ sq. yard coverage which is 21 mils. Q.9.What type of striping paints should be used and how soon can the lot be striped? A.9. Water based traffic paints are preferred. Allow the sealer to dry and cure at least 24 hr. after the application of the final coat of the sealer, prior to striping. If applied sooner, traffic markings may turn brown and blotchy. Most of the water borne traffic paints contain some fast evaporating solvents. These solvents extract lighter fractions from the binder (coal tar or asphalt) portion of the partially cured film of the sealer. The extract floats to the surface of the paint film, thus rendering it brown and blotchy. 46

48 FREQUENTLY ASKED QUESTIONS APPLICATION Q. 8. What type of striping paints should be used and how soon can the lot be striped? A. 8. Water based Acrylic Traffic Paints are preferred. Alkyd (oil) based paints are also used. a. Allow the sealer to dry and cure at least 24 hr. after the application of the final coat of the sealer, prior to striping. b. If applied sooner, traffic markings may turn brown and blotchy. Note: -Most of the water borne traffic paints contain some fast evaporating solvents. -These solvents extract lighter fractions from the binder (coal tar or asphalt) portion of the partially cured film of the sealer. -The extract floats to the surface of the paint film, thus rendering it brown and blotchy.. 47

49 FREQUENTLY ASKED QUESTIONS Mix Designs- Sand/Aggregate Q. 9. Can you explain sieve size, % retained, % passing, etc.? A. 9 a. Sieve sizes- Sand/aggregates must fall within a range of particle sizes, neither too coarse nor too fine. The sand is sifted through a set of screens with varying mesh sizes (openings in the screen). b. Percent retained means how much of 100 grams of sand was retained on the screen and, c. Percent passing is how much passed through the screen. Use your manufacturers recommended grades. Q.10.Why should we use sand? A.10. a. Traction/ skid resistance, Note- Be aware of the liability issues before making claims sealcoating will improve the skid resistance or make a surface slip resistant. b. Toughness of the cured coating film, c. A uniform textured, non-glare surface. D. It fills minor hairline cracks. Do not claim that it will fill larger cracks. 48

50 FREQUENTLY ASKED QUESTIONS Mix Designs-Additives Q.11. Why use latex additives? A.11. The use of latex additives is very common. There are many latex additives to impart all types of performance advantages. For example; a. Rubberizing additives improve flexibility, durability, toughness, etc. b. Faster drying additives help sealers dry fast. c. Water repellent additives improve water resistance of the cured sealer d. Thickening additives build the viscosity of sealcoatings diluted with large amounts of water. Suspend large amount of sand. Follow the manufacturer’s recommendations.. 49

51 FREQUENTLY ASKED QUESTIONS Mix Designs-Additives Q.12. What happens when you use different additives (different suppliers) in the same tank? Why did the viscosity go haywire? A. 12. The viscosity went haywire because the additives were not compatible with each other. Do not mix different additives and stick to manufacturer recommendations. Also the manufacturers’ warranty may be void if you use other additives. Additionally, use the additive recommended by your sealcoat manufacturer. Additive made by someone else may not be compatible with the sealer made by another manufacturer. Q.13. Why apply two coats, when one coat looks good enough? A. 13. Appearance is only part of the benefits. The sole purpose of sealcoating is to protect and preserve the asphalt. One coat may not last even half as two coats. It will provide only half (or less) of the protection and will wear out, prematurely. You will have to sealcoat more frequently if you used only one coat.. 50

52 FREQUENTLY ASKED QUESTIONS Mix Designs Q.14. How much water can I use? A.14. Follow the manufacturers’ recommendations. Normally gallons per 100 gallons of concentrated sealer are recommended. Higher percentages are recommended for mix designs that use additives and larger amounts of sand. Q.15.What is the deal with specifications using excessive amounts of sand, e.g. 18 lb. of sand in one of the FAA Specifications? A.15. Those are special sand slurry specifications and not used commonly for sealcoating specifications. The industry recommends a maximum of 8 lb. of sand per gallon. Very high sand loading (18 lb. for example) will result in a coating that will be poor in flexibility, adhesion and chemical resistance. Q. 16.Where can I get straight, objective answers? A. 16. From your supplier. Editor of the “Pavement” magazine.. 51

53 RIGHT?? Thanks for your time & attention and participation. 52


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