Application Guide                                               Tool Guide   

       Hawk Seale -21 Application and Equipment Guide 
     for Preserving Asphalt and Rejuvenating millings       Hawk Seale is a proprietary concentrate developed with Iowa State University formulated to rejuvenate and re-bond  asphalt millings to create a water resistant, non-tracking and non-eroding durable surface, that stands up to cold and hot climates and all types of traffic. 
 which are the two main causes of asphalt deterioration
NOTE--HS treated recycled asphalt may not have the luster or look of “Hot Mix” asphalt, finished surfaces can vary in smoothness, color and overall look due to a multiple of factors including  quality and composition of the millings as well as varying practices in laying the millings.
Consistency and Color- 
 HS-21 concentrate is brown in color but turns black when exposed to air. Viscosity is similar to 30 weight motor oil,  when mixed with water it will be thin to penetrate into the voids and fissures of the asphalt pavement.
When applied it is black in color, it can bring out the black in previously applied sealers on asphalt driveways and parking lots. 
Pavements may need to be re-striped after application.                                                                                Preparation and mixing –

• Add 8 to 9 parts water to 1-part HS-21 concentrate. Do NOT use cold water, allow water to warm up to air temperature then add to concentrate to avoid shocking the emulsion causing separation.
• Avoid prolonged  recirculation of the solution prior to application as it may cause separation of the copolymers. Some pumps can “dead-head” or add air to the solution causing separation of copolymers within minutes.
• We recommend “NO” prolonged circulation prior to actually beginning to apply the solution. Paint thinner may be added to break up this accumulation of copolymer to prevent the clogging of nozzles without affecting performance. 
• HS-21 is air activated,  avoid  vigorous mixing, splashing, and recirculation as it can cause the copolymers to separate and break from the water during mixing and application.  
• Paint Thinner can be used to thin copolymers if needed with affecting performance.
• When applying multiple large tankfuls of Solution we recommend a having a screen on the intake line.  Similar to window screen. 

        Approximate curing times vary depending on temperature.

• In temperatures above 90 degrees the millings can cure within an hour to a hard surface,  Mid- 80-degree temperatures will cure in an hour or two.
• Mid 70-degree temperatures will cure in 2 to 8 hours.
• Mid 60-degree temperatures will cure in 12 to 24 hours.
• Mid 50-degree temperatures can take 3 to 10 days to completely cure.

Colder temperatures ( 55 to 60 degrees ground temperature) will slow the curing process dramatically which can expose the treated millings to damage from large trucks, tractors, multi-axle trailers,4-wheelers, dirt bikes etc., for a longer period of time .
 
We do not recommend application below 55 to 60 degrees, especially if night time temperatures drop into the 30 to 40 degree range as penetration and bonding is reduced.
 *In cooler weather compacted millings may feel carpet-like when walking on them, until they fully cure to a hard durable surface.
  APPLICATION RATE- PRESERVING and Sealing ASPHALT  

• We recommend applying .35 to .4 tenths of a gallon of HS-21 per square yard applied in 3 coats to asphalt pavement to  fill the fissures, voids and cracks in the asphalt.
• Apply approximately half of the solution with the first coat, each successive cost will take less solution as the pavement is filled from the bottom up.
• Very porous surfaces may require more coats to “fill” the pavement to point of run-off signaling the fissures and voids in the pavement are “full”.  Solution will  puddle and begin to run off when pavement is fully saturated.
• Cracks larger than 1/4 inch should be filled with crack filler, also dirt, sand, trash and other materials should be removed from the surface of the pavement prior to application.
• HS-21 Solution can be applied with a sponge or heavy knap roller, sprinkle can and broom or sprayer for larger areas.

             *HS-21 is an adhesive product designed to bond asphalt and aggregate, 
             it will be sticky until it dries.
 NEW CONSTUCTION -   

• Millings do not have structural strength and rely on the base underneath to provide strength for a lasting roadway.
• We recommend there be an existing  solid  base, or constructing a new base with  4 to 5 inches of 2” rock or similar base material to support your millings.
• Spread and grade the millings to a minimum depth of  4 inches is recommended. .
•  Expect treated millings to compact about 30%.  

 COMPACTED MILLINGS APPLICATION-

• On Average millings will absorb approximately 1- gallon +/- of HS-21 solution per square yard over 3 passes.
• The amount of HS 21 solution is self-determining; apply each coat until it puddles or begins to run off.
• The 1st coat will absorb approximately ½ gallon per sq/yd,  the 2nd coat will absorb approx. a third of a gallon per square yard which can be applied as soon as the 1st coat is absorbed. The third pass will generally absorb less than a quarter of a gallon or the remainder of the solution.   
• It is better to apply more solution versus less than the recommended amount when applying to millings.
• Less than recommended rates may not provide the adhesion necessary to prevent raveling and erosion
• Any Re-compaction should be done immediately after application.
• In very hot weather the treated millings will harden within an hour or so. Larger aggregate will be crushed when using a heavy  steel roller which will create a mottled look. 
• Applying the 3rd coat after compaction in very hot weather will provide a nice finish and also will fill the voids and fissures to prevent air and water from entering the surface, which are the two main causes of asphalt failure.
•  Compaction can be done with a heavy roller or smooth tired vehicle, or plate compactors for small projects.

• “Light” traffic can begin Immediately or as soon as solution is absorbed and dry.
• Avoid overnight parking until the millings have cured typically in a couple days depending on temperature.
• Fully Curing time varies from a couple hours to a week  depending on temperature.
• ** You may notice a carpet like feel as you walk on the treated millings; this will disappear as the millings cure.
•  DO NOT use “vibration” on treated millings after 3 hours from application  as the bonding process can be damaged.

  UN-COMPACTED MILLINGS APPLICATION RATE-

• Un-compacted millings will absorb approximately f 1- Gallon +/- of  HS-21 solution per square yard in 3 passes.

• Expect to use about half of your HS-21 solution on the first application, applying the HS-solution to the point of puddling.
• Apply the 2nd coat immediately after the 1st coat has been absorbed, the second coat will take less solution.
•  Caution- in temperatures in the 90's the treated millings immediately after the second coat is applied even if still wet in 90 degree weather.
• In cooler weather in the 70s and 80'S all 3 coats can be applied prior to compaction. 
• Again apply the 3rd coat to the point of puddling and/or running off to fill the voids and fissures to prevent air and water from entering the surface which are the two main causes of asphalt failure. .
• It is better to apply more solution versus less than the recommended amount when applying to millings. Less than recommended rates may not provide the adhesion necessary to prevent raveling and erosion
• Applying more than 1 gallon per sq/yd may be needed in some cases when millings do not have enough asphalt for good adhesion.

• HS-21 solution can also be incorporated into the top 2 to 3 inches of un-compacted millings form more uniform depth of the solution. 
• Compaction can be done immediately after the 2nd and/or 3rd application of the HS-solution.

 “Light” traffic can begin Immediately or as soon as surface is dry.

• Avoid overnight parking until the millings have cured typically in a couple days depending on temperature.

 ** You may notice a carpet like feel as you walk on the treated millings; this will disappear as the millings cure. 

• Cooler temperatures below 65 degrees will slow the curing process significantly adding a couple weeks to fully cure before the surface is safe from damage.

 Compaction is very important in creating a durable roadway.

• Vibration can be used as needed
•  Do not over compact- 3 to 4 passes with heavy roller or smooth tired vehicle is usually adequate.
• When compacting be careful to not over compact your millings as it can lead to rippling and flaking of the surface. Avoid short back and forth motion.  Long full-length runs will provide a smoother surface.
• Plate compactors can be used for smaller projects and trimming close to buildings etc.

 *DO NOT use ”vibration with heavy vibeatory Rollers”  after 3 hours of application as the chemical bonding process can be damaged and separation of the aggregate can occur.
 
*HS-21 rejuvenation of millings is a “cold process” versus typical “HOT Mix”  and requires
 a curing time similar to concrete to set up into a hard surface.

•  Do not apply below 60 degrees ground temperatures or if there is danger of freezing at night as the HS solution will not penetrate and cure to re-bond the millings properly.
  

Traffic-

• Light smooth tired traffic will help in compacting and bonding the millings, and can begin immediately.
• Traffic should alternate driving patterns to compact the surface evenly and avoid creating tire paths or rutting.
• Avoid overnight parking  and aggressive tired vehicles such as 4 wheelers and  farm tractors until millings have fully cured.
• You may notice a “soft carpet like feeling of the surface underfoot” as you walk on it right after application.     
• This “soft feel” will disappear as the Hawk Seale Blend cures to a hard durable surface  depending on temperature.
•  Ground Surface Temperature of 56 degrees minimum and above is important for timely curing as the millings are susceptible to damage during the curing process.  

 Handling and Clean Up-

• Equipment and tools should be rinsed or cleaned  immediately after use-
• Use WD-40 or equivalent keep the pump, valves and nozzles free.  
• HS-21 solution will leave a film residue in and on tools and tanks etc. – Expect some tools to be a one-time use.
• Zep Industrial Degreaser, WD-40 or diesel or similar products can be used for cleaning.

• Boots, Gloves, goggles and coveralls are recommended. 
• HS- 21 concentrate will stick to everything it comes in contact with. 
• Clean up with Zep Industrial Degreaser,  WD-40 or its equivalent , or Diesel
• Dried on solution can be cut with acetone or paint stripper. 
• WD 40 or Diesel fuel can also be used to keep equipment valves etc. free when not in use.
• Un-used Hawk Seal concentrate and mixed solution can be stored in an airtight container similar to latex paint
•  Keep from freezing, shelf life is limited.

 * Garden and lawn sprayers typically do not have the volume needed to saturate the millings in a timely fashion. Also HS is an adhesive product and tends to plug small nozzles and leaves a residue on anything it comes into contact with.
See our Sprayer Guide for more information on tools and equipment. 
               
 MIXING and HANDLING-

• Used cage tanks, drums and other larger containers  are ideal for mixing HS-21 solution.
•   Use “Tempered Air Temperature Water” added to the concentrate to prevent shocking the HS emulsion.
• Avoid aggressive stirring or agitation and/or prolonged recirculation of solution as it can cause the Copolymers to break away from the water and separate.
• Some pumps can add air or dead-head and can cause the copolymers to separate and clog pump and equipment. 

      Paint Thinner can be used to thin the thick                        copolymer to prevent clogging nozzles. 
Pumps for sprayers-

• Water trash pumps or other pumps with plastic or metal impellers etc. are preferred.
• We prefer water trash pumps as they are high volume with low pressure to minimize spray drift.
  • Larger ½ inch 80-50 fan jet nozzles work well for application spaced 6 to 12 inches apart for booms and will work for  wands.
  • Available from-https://asphaltstore.com/products/spray-tips-for-sealcoating/
• Do not agitate solution prior to application as some style pumps can add air to the solution which can lead to separation and coagulation.
• Do not use agricultural or garden sprayer pumps as they can seize up due to the adhesive ingredients in HS-21 solution as HS solution will leave a sticky residue.   HS-21 may cause rubber components to swell and fail.                                                     
• Be sure to rinse your system after use.    
• Tools, tanks, and other equipment will be left with a sticky black residue.  WD-40, Degreasers,  Diesel,  or similar products can be used to remove the HS residue
• Expect containers to be permanently stained and some tools to be a one-time use.  

No guarantees of performance are implied or offered due our lack of control over mixing and application, surfaces and materials applied to, and weather conditions.     
Contractors and Applicators are welcome.         
For more specific information
Email us at -   Hawkseale@gmail.com  
​Rev 7-21-22

                                 
           
 
 

 Tips on constructing sprayers and other tools to apply HS Solution