Advanced Sealcoating NPE, FEB 1, 2007, NASVILLE, TN TOPIC HOW TO IMPROVE THE PERFORMANCE OF YOUR SEALER Sealer Composition Mix Designs Coverage Rates, Film Thickness Optimum Cure & Film Formation Presented by Girish Dubey President, STAR, Inc.

DESIGNED FOR SEALCOATING PROFESSIONALS WHO WANT TO LEARN BEYOND THE BASICS OF SEALCOATINGS. TO MAKE EVERY JOB LOOK & PERFORM THE VERY BEST. PERFORMANCE IS THE CENTERPIECE

These facts are applicable to most water based coatings. All are very critical. These facts are applicable to most water based coatings. All are very critical. 1. GOOD QUALITY SEALER- Meets specifications, and has an established track record. 2. RIGHT MIX DESIGN- Follow recommendations (manufacturer or job specs.). 3. RECOMMENDED RATES- To deposit the right amount of sealer on the pavement. 4. DRY & CURE UNDER RIGHT AMBIENT CONDITIONS- temperature, humidity, wind velocity. PERFORMANCE THE CENTERPIECE

SEALCOATING BASICS SEALCOATINGS ARE ; WATER-BASED COATINGS, WATER-BASED COATINGS, A STABLE DISPERSIONS OF; a. BINDER (RT-12 or AC) is the backbone of the sealer and provides the protection to the pavement against the elements.- weather, salt, water, chemicals, etc. b. Clay and Fillers- Provide tensile strength, toughness, body and stability. c. Water- is the medium in which tar, clay fillers are dispersed. d. Emulsifiers, specialty chemicals- help dispersion, provide stability and special properties.

What Makes A Good Sealer How Can You Tell? 1. Meets /or Exceeds Specifications: (ASTM, FEDERAL, FAA, etc.). 2. Proven Performance: Good Track Record. 3. Dark, Chocolate Brown in Color- Indicating Fine Dispersion of Tar or AC. 4. pH Below 7 slightly acidic- May be unstable, - Over 8- Alkaline- Prone to water sensitivity. 5. References, Comparative Evaluation

What Makes A Good Sealer How Can You Tell? 4. pH of the sealer, 7-8: Lower Ph-slightly Acidic may induce instability. Higher pH-Alkaline- Prone to water sensitivity. 5. References, Comparative Test Data.

TYPICAL SEALER COMPOSITION Undiluted (as manufactured)

MIX DESIGNS AN OVERVIEW. SEALCOATING IS NEVER APPLIED IN ITS CONCENTRATED FORM GENERALLY MIXED WITH; 1. WATER - FOR FLUIDITY, WORKABILITY, 2. SILICA SAND - TEXTURING, - TRACTION, - FILLING VOIDS (profile, minor surface cracks), 3. ADDITIVES (OPTIONAL) - PERFORMANCE BOOSTING (Flexibility, Toughness, Resistance to salt, water, chemicals..), - Drying Accelerator

MIX DESIGNS AN OVERVIEW. STANDARD SYSTEM: A 2-coat system Mix Design SEALCOATING (CONC) 100 GAL Mix Design SEALCOATING (CONC) 100 GAL WATER (30% BY VOL.) 30 GAL SILICA SAND /aggregate lb TOTAL 145 GAL. Application Rates, Gal (conc.) Sealer/Sq. Yard: Ist. Coat IInd. Coat TOTAL (2 COATS) : GAL. /SQ. YARD. TOTAL (2 COATS) : GAL. /SQ. YARD.

MIX DESIGNS

Hazards in Altering the Mix Designs Hazards in Altering the Mix Designs Follow the recommended mix designs Changing the mix design may cause performance problems 1. WATER: 1. WATER: A. EXCESSIVE- - Thinner Dry Film Thickness (D.F.T.) - Poor Durability, - Premature failure. Important ADJUST APPLICATION RATE TO MAINTAIN DRY FILM THICKNESS. B. NOT ENOUGH WATER- - Poor Flow, uneven appearance - The sealer may not wet out the surface properly for good adhesion. - Tracking is possible.

Hazards in Altering the Mix Designs The coverage rate will have to be adjusted to account for the higher amounts of water to maintain the same Dry Film Thickness (DFT)

Hazards in Altering the Mix Designs Hazards in Altering the Mix Designs 2. SAND/ AGGREGATE 2. SAND/ AGGREGATE EXCESSIVE (OVER 5,6 LB)- POOR FLEXIBILITY, BRITTLENSS POOR ADHESION TO PAVEMENT POOR ANCHORING,SAND ROLL OUT PREMATURE FAILURE NONE OR VERY LITTLE (<1 LB) REDUCED TRACTION/SKID RESISTANCE UNEVEN TEXTURE AND APPEARANCE SOFT SHEEN (REFLECTANCE) PAVEMENT VOIDS NOT FILLED

Hazards in Altering the Mix Designs Hazards in Altering the Mix Designs 3. ADDITIVES 3. ADDITIVES - VERY SELECTIVE. - VERY SELECTIVE. - FOLLOW MANUFACTURER’S RECOMMENDATIONS. - FOLLOW MANUFACTURER’S RECOMMENDATIONS. - MAY NOT BE COMPATIBLE WTH THE SEALER. - MAY NOT BE COMPATIBLE WTH THE SEALER. EXCESSIVE (OVER 5 %): EXCESSIVE (OVER 5 %): - WASTE OF MONEY - MAY ADVERSELY AFFECT PROPERTIES NOT ENOUGH (LESS THAN 1 %): - INEFFECTIVE - MARGINAL PERFORMANCE IMPROVEMENT, - MOSTLY FOR NAMESAKE.

COVERAGE RATES AREA COVERED BY A GALLON OF (undiluted) SEALER COVERAGE RATES AREA COVERED BY A GALLON OF (undiluted) SEALER EXPRESSED IN 2 WAYS; 1. Gallons of sealer per square yard (gal./sq. yard).Most commonly used. or or 2. Square feet area covered by one gallon of undiluted sealer. A typical Coverage Rate for a two (2) coat application is gal (undiluted) sealer/sq. yard 1 st Coat gal./sq. yd. 2 nd Coat gal./sq. yd.

CRITICAL FACTORS FOR SEALER PERORMANCE 1. COVERAGE RATE Sealer must be applied at the recommended coverage rate. It is assured by measuring: -WET FILM THICKNESS (W.F.T.) & -Calculating DRY FILM THICKNESS (D.F.T.) 2. CURE CONDITIONS: Must be right. TEMPERATURE (ground and surface) HUMIDITY OR RELATIVE HUMIDITY(R.H.)- HUMIDITY OR RELATIVE HUMIDITY(R.H.)- Capacity of air to hold ambient temperature. WIND VELOCITY

COVERAGE RATE CONFIRMATION-SEALER FILM THICKNESS STEP 1 STEP 1 DETERMINE THE WET FILM THICKNESS (W.F.T.) Two methods: 1. Calculate- Apply sealer on a known area (sq. feet) and divide gallons used, to get coverage in sq. ft./gallon. W.F.T. (IN MILS) = 1604/COVERAGE IN SQ.FT.GALLON. Discussed later.. Use a wet film thickness gauge

COVERAGE RATE CONFIRMATION-SEALER FILM THICKNESS STEP-2 Determine the solids % by Volume 2. Calculate % solids by volume Water (% by Vol.) = 101.2/155.9 = 65% Solids (% by Vol.) = 100% - 65% = 35% MIX DESIGN INGREDIENTSGALLONSWATER (% VOL.) SEALER (CONC.)10060 WATER *40 SAND/ AGGREGATE13.9 (300 LB)0 ADDITIVE21.2 TOTAL * More water while using an additive

Determine the wet film thickness Wet Film Thickness is expressed in mils Wet Film Thickness is expressed in mils 1 MIL= 1/1000 inch. 1 MIL= 1/1000 inch. IF THE ; a. COVERAGE IS KNOWN IN SQ. Ft./GAL. DIVIDE INTO 1604 (CONSTANT) For example for 50 sq. ft/gal., W.F.T. = 1604/50 = 32 MILS = one gallon of coating covers 1604 sq. ft. in one (1) mil film thickness. in one (1) mil film thickness. b. COVERAGE KNOWN IN GAL./SQ. YARD. MULTIPLY WITH (CONSTANT) For example 0.18 Gal./Sq. Yard W.F.T. = X 0.18 = 32 mils. COVERAGE RATE CONFIRMATION-SEALER FILM THICKNESS Step-3

STEP 4 Calculate Dry Film Thickness (D.F.T.) SIMPLE MULTIPLY WET FILM THICKNESS (W.F.T.) WITH SOLIDS % BYVOLUME) D.F.T = W.F.T. x % solids by vol. EXAMPLE D.F.T. = 32 mils x 0.35 = 11.2 mils. COVERAGE RATE CONFIRMATION-SEALER FILM THICKNESS

DRYING & CURING o f SEALCOATINGS DRYING- EARLY STAGES CURING-FINAL FILM SET UP SEALCOATINGS CURE THROUGH: SEALCOATINGS CURE THROUGH: 1. RELEASE OF WATER, THROUGH EVAPORATION 2. FILM SHRINKS IN VOLUME 3. PARTICLES OF THE BINDER AND FILLER ARE FORCED TO COALESCE 4. BINDER PARTICLES SOFTEN, FUSE AND ENVELOPE CLAY/FILLER PARTICLES. 5. CONTINUOUS SEALER FILM IS FORMED.

DRYING & CURING OF SEALCOATINGS WE WILL DISCUSS 1. CURE MECHANISM 2. FACTORS AFFECTING CURE TEMPERATURE- (SURAFCE & AMBIENT) RELATIVE HUMIDITY (% R.H.) RELATIVE HUMIDITY (% R.H.) WIND VELOCITY WIND VELOCITY

DRYING & CURING OF SEALCOATINGS 1. Cure Mechanism:  Sealcoatings are water-based  Sealcoatings are water-based  Water represents the largest portion of mix design (65%)  Water represents the largest portion of mix design (65%)  They dry/ cure by releasing water.  They dry/ cure by releasing water.  As water evaporates, the film shrinks in volume (to 35% remaining as dry film)  As water evaporates, the film shrinks in volume (to 35% remaining as dry film)  Binder (tar/asphalt) and clay/filler particles are forced in closer proximity  Binder (tar/asphalt) and clay/filler particles are forced in closer proximity  Binder particles touch each other and start fusing, thus enveloping clay/filler particles and bonding to the pavement  Binder particles touch each other and start fusing, thus enveloping clay/filler particles and bonding to the pavement  Continuous film results-Free of voids  Continuous film results-Free of voids

DRYING & CURING OF SEALCOATINGS CURE MECHANISM: Volume Shrinkage in Film Sealer Solids only WATER

D RYING & CURING OF SEALCOATINGS CURE MECHANISM: Sealer wet film:  Is multi-layered (composite) layer of many thin films  Each layer dries individually from top to bottom,  The release of water becomes more difficult as each layer dries  Bottom layer takes longer to cure  The sealer may appear fully dry on the surface but the bottom layers may still be soft. Allow sufficient drying.

DRYING & CURING OF SEALCOATINGS CURE MECHANISM: DRYING & CURING OF SEALCOATINGS CURE MECHANISM:

2. CURE CONDITIONS Factors Affecting Drying TEMPERATURE TEMPERATURE (ambient & surface) (ambient & surface) Min F and rising is preferred Min F and rising is preferred A. Lower temperatures : POOR FILM FORMATION. BINDER PARTICLES DO NOT SOFTEN PROPERLY TO FUSE AND FORM A CONTINOUS FILM It may result in: POOR PERFORMANCE. SEALER PROPERTIES ARE LOST, SELDOM RECOVER. GRAY COLOR ON INITIAL DRYING.

Factors Affecting Drying (cont..) B. Higher Temperatures: Over 90 o F WATER FLASHES OFF- IMMOBILIZING THE BINDER PARTICLES IN THE FILM. IT MAY RESULT INTO: TRACKING PINHOLING SAND BALLING DRYING IN THE WINDROW POOR & STREAKY APPEARANCE Humidity Capacity of the surrounding air to hold water Low Humidity: Very favorable for drying and cure. Will speed up drying. High Humidity- Slow cure. Need more drying time. WIND VELOCITY Will carry volatiles away.

Humidity Water Vapor in the Air Additional Notes Relative Humidity (R.H.) : Capacity (%) of air to hold water vapor at a particular temperature. - Low R.H.- MEANS THE AIR HAS ROOM TO ABSORB MORE WATER VAPOR. 30% MEANS 30% of the capacity used up- 70% remaining. Good for sealer drying. - High R.H.- MEANS THE AIR HAS VERY LITTLE ROOM ABSORB MORE WATER VAPOR. 80% MEANS 8 0% of the capacity used up- 20% remaining. Poor for sealer drying. Air is like a blotting paper.- It will keep absorbing water as long as it is not saturated. The capacity of the Air to hold water vapor will change with temperature. Higher temperature – Higher the capacity. Air will expand.

CAPACITY OF AIR TO HOLD WATER SATURATION VS. TEMPERATURE Temperature ° CGrams of water

EVAPORATION VARIOUS R.H. and TEMPERATURE Relative HumidityTemperature, Deg. Celsius

DRYING & CURING o f SEALCOATINGS Favorable Conditions:  Moderate Temperatures  Low humidity  Low humidity  Moderate wind velocity  Moderate wind velocity Unfavorable Conditions:  Low Temperatures  High humidity  High humidity  Stagnant wind  Stagnant windGENERAL  Allow each coat to dry sufficiently, prior to applying the subsequent coating.  Take light vehicular traffic (application equipment - e.g. spray rig) scuffing and tearing.

ADDITIVES 1. WHAT ARE ADDITIVES?  DEFINITION  DEFINITION  TYPES  TYPES 2. WHAT THEY DO & HOW THEY IMPROVE THE SEALER PERFORMANCE?  FAA QUALIFYING TESTS  FAA QUALIFYING TESTS 3. WHAT THEY DO NOT DO? COMPENSATE FOR POOR PERFORMANCE, IF EXCESSIVE WATER OR SAND IS USED.

DEFINITIONS ADDTIVES ARE THE Materials Added to Sealcoatings to ACCOMPLISH SPECIFIC OBJECTIVES ADDITIVES

ADDITIVES OBJECTIVES IMPROVED PROPERTIES: Flexibility and elongation Toughness Water resistance Resistance to chemicals, de-icing salts, oils, fats, grease etc.. FAST DRYING: Even under not-so-ideal weather conditions. UNIFORM DRY COLOR: Under shade or shine. THICKENING: To accommodate large amounts of water. SAND OR AGGREGATE SUSPENSION: No streaking, NO SAND BALLING.

ADDITIVES for PERFORMANCE BOOSTING Have been used for the last years. Have been used for the last years. Extensively used since mid-70’s FAA specified A/B (Acrylonitrile/butadiene) rubber latex for coal tar based sealers.

PERFORMANCE BOOSTING RUBBERIZING ADDITIVES FOR SEALCOATINGS 1. REDUCE TEMPERATURE SUSCEPTIBILITY; Reduce Tack and flow in summer & brittleness in winter months. 2. INCREASE TOUGHNESS; Greater resistance to abrasion, scour and wear. Better retention of aggregates. 3. INCREASE FLEXIBILITY AND ADHESION; Better anchoring of aggregates. OTHER BENEFITS THICKENING Due to pH alteration of the coating system. FAST DRYING Even under not-so-ideal weather conditions. UNIFORM DRIED COLOR PERFORMANCE BOOSTING RUBBERIZING ADDITIVES FOR SEALCOATINGS 1. REDUCE TEMPERATURE SUSCEPTIBILITY; Reduce Tack and flow in summer & brittleness in winter months. 2. INCREASE TOUGHNESS; Greater resistance to abrasion, scour and wear. Better retention of aggregates. 3. INCREASE FLEXIBILITY AND ADHESION; Better anchoring of aggregates. OTHER BENEFITS THICKENING Due to pH alteration of the coating system. FAST DRYING Even under not-so-ideal weather conditions. UNIFORM DRIED COLOR

RUBBERIZING ADDITIVES HOW DO THEY WORK Rubberizing additives are water emulsion of polymer molecules. Polymers (selected) have; Large chain length, heavily branched, Large chain length, heavily branched, Excellent resistance to chemicals, salts, water, weathering, etc. Excellent resistance to chemicals, salts, water, weathering, etc. When mixed with the sealer: Polymer chains in sealcoating materials, Polymer chains in sealcoating materials, 1. F orm a flexible and tough network of polymer molecules, 2. Hold binder (tar, asphalt), fillers and aggregate uniformly.

AS THE SEALCOATING DRIES Polymer network tightens within the film, it forces water out at a uniform rate, producing uniform dry color. Polymer network tightens within the film, it forces water out at a uniform rate, producing uniform dry color. Polymer fuses onto the tar (asphalt) particles thus improving; Polymer fuses onto the tar (asphalt) particles thus improving; ELXIBILITY, TOUGHNESS FUEL & CHEMICAL RESISTANCE SAND SUSPESION AND ANCHORING FAST DRYING.

THE POLYMER FOR THE ADDITIVE MUST BE RESISTANT TO: WEATHERING GASOLINE, OILS, FATS SALTSPETROCHEMICALS OTHER CHEMICALS.. WEAKNESS IN THE POLYMER (ADDITIVE) WILL INTRODUCE WEAK LINKS IN THE SEALER AND MAY CAUSE PREMATURE FAILURE. WEAKNESS IN THE POLYMER (ADDITIVE) WILL INTRODUCE WEAK LINKS IN THE SEALER AND MAY CAUSE PREMATURE FAILURE.

Majority of the POLYMERIC ADDITIVES: º Produce Thickening, º Speed up Drying Time, º Produce Uniform Dry Color, º Help to Suspend aggregates. But they differ in their abilities to; º Reinforce the properties like, Flexibility, Toughness, Temperature Susceptibility etc. ºImprove resistance to Chemicals, oils, fats, grease, de-icing salts, aromatic fuels etc.

ADDITIVES The Right Additive Used in Right Proportion will; Reinforce the properties, Improve the overall performance BUT WILL NOT Mix design deficiencies caused by the excessive amounts of ; Water- thinner dry films Sand/Aggregate- May not supply enough binder to satisfy the demand of the excessive amounts of aggregates used in the mix. Sand/Aggregate- May not supply enough binder to satisfy the demand of the excessive amounts of aggregates used in the mix.

ADDITIVES: CONCLUSIONS 1.Acrylonitrile/Butadiene polymers (NBR TYPE) have the best overall properties. - They reinforce and boost the properties of asphalt and coal-tar based sealers. - better resistance to oils and other petrochemicals than Styrene/Butadiene polymers. Rest of the properties are similar. 2.Polyvinyl Acetate/acrylic co-polymers (PVAs) are not recommended due to poor water and alkali resistance. Introduce weak spots in the film when attacked by water. Useful only as thickeners and for speeding up drying. ADDITIVES: CONCLUSIONS 1.Acrylonitrile/Butadiene polymers (NBR TYPE) have the best overall properties. - They reinforce and boost the properties of asphalt and coal-tar based sealers. - better resistance to oils and other petrochemicals than Styrene/Butadiene polymers. Rest of the properties are similar. 2.Polyvinyl Acetate/acrylic co-polymers (PVAs) are not recommended due to poor water and alkali resistance. Introduce weak spots in the film when attacked by water. Useful only as thickeners and for speeding up drying.