High Friction 

Surface Treatment 

Installation and Inspection Pocket Guide

Image source: The Transtec Group
ii

TECHNICAL DOCUMENTATION PAGE

1. Report No.

FHWA-SA-22-15

2. Government 

Accession No.

3. Recipient's Catalog No.

 

4. Title and Subtitle

High Friction Surface Treatment: 

Installation and Inspection Pocket 

Guide

5. Report Date

June 2022

6. Performing Organization 

Code

7.Author(s) 

David Merritt (Transtec Group), Scott 

Himes (VHB) 

8. Performing Organization 

Report No.

9. Performing Organization Name and 

Address

Vanasse Hangen Brustlin, Inc (VHB)

940 Main Campus Dr Ste 500

Raleigh, NC 27606

10. Work Unit No.

11. Contract or Grant No.

DTFH6116D00040L

12. Sponsoring Agency Name and 

Address

Federal Highway Administration 

Office of Safety 

1200 New Jersey Ave., SE

Washington, DC 20590

13. Type of Report and 

Period

Final Report, June 2022

14. Sponsoring Agency Code

FHWA

15. Supplementary Notes

The contract manager for this report was Joseph Cheung. 
iii

16. Abstract

This Guide is a resource for High Friction Surface Treatments and 

recommendations on applications, site selection, installation, and 

performance monitoring. This Guide also includes an inspection guide 

that agencies can use to establish inspection protocols for HFST 

installation and a resource section. 

17. Key Words: 

High friction surface 

treatments, curves, 

intersections, ramps, 

safety, pavement 

friction

18. Distribution Statement

No restrictions.

19. Security 

Classif. (of this 

report)

Unclassified

20. Security Classif. (of 

this page) Unclassified

21. No. of 

Pages

 77

22. 

Price

Form DOT F 1700.7 (8-72) Reproduction of completed pages 

authorized
iv
v 

Notice 

This document is disseminated under the sponsorship of the 

U.S. Department of Transportation in the interest of 

information exchange. The U.S. Government assumes no 

liability for the use of the information contained in this 

document.

The U.S. Government does not endorse companies, 

products or manufacturers. Trademarks or company and 

manufacturers’ names appear in this publication only 

because they are considered essential to the objective of 

the publication. They are included for informational 

purposes only and are not intended to reflect a 

preference, approval, or endorsement of any one product 

or entity.

Non-Binding Contents Disclaimer

Except for the statutes and regulations cited within, the 

contents of this document do not have the force and 

effect of law and are not meant to bind the public in any 

way. This document is intended only to provide clarity to 

the public regarding existing requirements under the law or 

agency policies.

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides highquality information to serve Government, industry, and the 

public in a manner that promotes public understanding. 

Standards and policies are used to ensure and maximize 

the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and 

adjusts its programs and processes to ensure continuous 

quality improvement.
vi

CONTENTS

OVERVIEW OF HFST INSTALLATION .......................................... 1 

High Friction Surface Treatment (HFST)................................ 2 

Applications and Precautions........................................... 3 

HFST Installation................................................................... 4 

PRE-CONSTRUCTION ................................................................ 5 

Quality Control Plan (QCP)................................................... 6 

QCP Administrator.............................................................. 7 

Materials Verification ............................................................. 7 

HFST MATERIALS ....................................................................... 8 

Resin Binder............................................................................. 9 

Calcined Bauxite Aggregate .............................................10

SURFACE PREPARATION ......................................................... 11

Treatment of Pavement Distresses.....................................12

Cleaning and Roughening .................................................13

Striping and Pavement Marking Removal and Masking . 15

Protection of Joints and Drainage Structures...................17

Protection of the Prepared Surface Prior to Application 19

HFST APPLICATION.................................................................. 20

Application Considerations and Methods........................21

Manual Application.............................................................22

Resin Binder Proportioning and Blending.......................25

Resin Binder Application..................................................27

Aggregate Application ...................................................30

Fully-Automated Application .............................................32

Resin Binder Application..................................................34

Aggregate Application ...................................................36

AGGREGATE REMOVAL.......................................................... 37

Methods ................................................................................38

Timing.....................................................................................40

Reclamation .........................................................................40

Inspection..............................................................................41

FINISHED SURFACE INSPECTION............................................. 43
vii

ACCEPTANCE TESTING ........................................................... 46

Friction Testing ......................................................................47

Test Methods .....................................................................47

Inspection ..........................................................................48

Macrotexture Testing...........................................................48

Test Methods .....................................................................48

Inspection ..........................................................................49

Other Testing.........................................................................49

EARLY-AGE MONITORING...................................................... 50

Uncured Resin Binder...........................................................51

Aggregate Loss and Re-Sweeping ....................................51

Delamination ........................................................................52

Aggregate Polishing ............................................................54

Discoloration .........................................................................55

Surface Wear Loss of HFST ...................................................56

Friction Loss............................................................................57

Failure of Underlying Pavement .........................................57

INSPECTION CHECKLIST.......................................................... 59

ADDITIONAL RESOURCES ....................................................... 68
1 

OVERVIEW OF 

HFST 

INSTALLATION

Image source: The Transtec Group
2 

High Friction Surface Treatment (HFST)

HFST is a pavement surface treatment used specifically to 

dramatically increase the skid resistance of virtually any 

pavement surface for the purpose of reducing frictionrelated crashes. HFST is installed by spreading a thin layer of 

polymeric resin binder (typically epoxy or polyester) over 

the pavement surface, then broadcasting or dropping a 1-

3 mm nominal-size polish and abrasion-resistant aggregate 

onto the resin layer. The finished surface is a thin, 

superficial, pavement surface treatment that can be 

applied during a short closure (e.g., 6-8 hours) of the 

roadway. Figure 1 shows an example of HFST placed over a 

conventional asphalt pavement surface.

© The Transtec Group

Figure 1. Photograph. HFST placed over a conventional asphalt 

pavement surface.1 

1Merritt, D. K., Tallon, R., and Watson, R. P. (2020). Developing CrashModification Factors for High-Friction Surface Treatments: Friction Change 

Report. Federal Highway Administration FHWA Research Report FHWAHRT-20-062. McLean, VA.
3 

Applications and Precautions

• HFST is used for applications where friction demand 

exceeds friction supply from the existing pavement 

surface. HFST is effective for reducing both wet and dry 

weather friction-related crashes.

• Primary usage includes horizontal curves, ramps, and 

intersections. 

• HFST does not provide any pavement preservation 

benefits – it is used specifically for friction 

enhancement. 

• HFST is different from thin-polymer bridge deck overlays. 

While the polymeric resin binder and installation 

methods used for polymer bridge deck overlays are 

similar to that used for HFST, bridge deck overlays are 

designed to help seal and preserve the bridge deck 

while also enhancing surface friction. Different 

aggregate materials are typically used for bridge deck 

overlays. 

• HFST performs the best when applied to structurally 

sound pavement but will still provide immediate safety 

benefit if short-term performance is acceptable.
4 

HFST Installation

The following are key components of an HFST installation 

which will be discussed in more detail throughout this 

Installation and Inspection Pocket Guide: 

1. Pre-Construction 

2. HFST Materials

3. Surface Preparation

4. HFST Application

5. Aggregate Removal

6. Finished Surface Inspection

7. Acceptance Testing

8. Early-Age Monitoring
5 

PRE- CONSTRUCTION

Image source: The Transtec Group
6 

Quality Control Plan (QCP)

QCPs allow the installer to detail every aspect of their plan 

for installation of HFST. QCPs are typically approved by the 

owner agency and allow the agency to provide input on 

various aspects of the installation before construction 

begins. QCPs also allow the agency to hold an installer 

accountable for practices outlined in the plan. 

Carefully review the contractor/installer QCP well in 

advance of installation to verify: 

• Schedule for the test strip and full-scale/production of 

HFST placement (if test strip is to be completed 

separately).

• Description of equipment for placing HFST.

• Methods for conditioning, metering, blending, and 

applying resin binder.

• Methods for applying aggregate, including timing of 

placement onto resin binder.

• Methods for monitoring and documenting material 

usage.

• Method for protecting areas that will not receive HFST.

• Description of acceptable environmental conditions 

(temperature and precipitation) for placing HFST.

• Cure time and time to opening to traffic estimates for 

HFST.

• Storage and handling of HFST materials.

• Disposal and recycling of excess HFST and containers.

• Contingency plan for possible failure during the HFST 

application.

• Name of the certified independent testing laboratory.
7 

• Key personnel and contact information.

• All project certifications and test results. 

QCP Administrator

The installer typically identifies and provides contact 

information for the QCP administrator who has full authority 

to institute any action necessary for the successful 

operation of the QCP. Other key personnel, such as an 

on-site Lead Technician are also typically identified. 

Materials Verification

In advance of installation, verify that materials supplied to 

the project meet specifications either through agency 

testing or from certified test results provided by the installer.

If qualified products lists (QPLs) are used for pre-approval of 

materials, verify that the materials supplied to the project 

are current on the owner agency’s QPL. 

If required by the project specification, verify that a resin 

binder manufacturer’s representative is present for the 

initial/test strip installation. 
8 

HFST 

MATERIALS

Image source: The Transtec Group
9 

HFST consists of two materials: polymeric resin binder and 

calcined bauxite aggregate. As non-conventional 

materials, there are special considerations for handling and 

testing of HFST resin binder and aggregate materials. Key 

items for inspection of these materials prior to and during 

installation are discussed below.

Resin Binder 

• Verify that resin binder type and brand supplied to the 

project site is what was specified in the QCP and 

approved for use.

• Verify that resin binder conforms to agency 

specifications if certified test results were provided by 

the installer in lieu of agency testing.

• Verify proper storage of materials for ambient 

conditions. 

• Verify that resin binder components are stored in 

sealed, watertight containers.

• Follow Manufacturer's recommendations for storage of 

the resin binder (heated/cooled/shaded locations as 

required).

• Verify resin binder component containers are clearly 

labeled with: resin component (e.g., Part A, Part B, 

etc.), brand name, name of manufacturer, lot or batch 

number, temperature range for storage, expiration 

date, and quantity of material in container.

• Sample materials for verification testing on-site as 

called for by specification.

• Verify that adequate quantities of resin binder 

components for the intended installation are on-site or 

accessible near the project site.
10

Calcined Bauxite Aggregate

• Verify that aggregate packaging is clearly labeled 

with: type of aggregate, manufacturer, and location of 

processing.

• Verify that aggregate conforms to agency 

specifications if certified test results were provided by 

the installer in lieu of agency testing. 

• Verify that aggregate is packaged and stored in such 

a way to protect it from rain.

• Verify that adequate quantity of aggregate for the 

intended installation is on-site or accessible near the 

project site.

• Sample materials for verification testing on-site as 

called for by specification.

• Assess aggregate cleanliness:

o Examine aggregate material in packaging or 

installation vehicle for presence of foreign matter.

o Observe loading of aggregate into installation 

vehicle to check for segregation and assess 

cleanliness (dust generation).

• Verify aggregate is dry and there is no visible moisture 

on the stockpile or within the stockpile when sampled 

by hand. Sample and test for moisture if questionable.

• If reclaimed aggregate is permitted, verify that 

reclaimed material has been remixed with virgin 

material at the specified minimum ratio (typically 2:1 or 

3:1 virgin to reclaimed). 
11

SURFACE 

PREPARATION

Image source: The Transtec Group
12

Preparation of the underlying pavement surface is critical 

for the installation and long-term performance of HFST. The 

various aspects of surface preparation prior to HFST 

application are discussed below. 

Treatment of Pavement Distresses

The types of underlying pavement distresses to be 

addressed prior to HFST application are typically outlined in 

the project plans and specifications. Note that some 

distresses may need patching or the complete removal 

and replacement of pavement surfaces, which typically 

involves 30 days of cure time before HFST can be applied. 

Most agency specifications require pre-treatment of nonworking cracks wider than 0.25 inches with HFST resin 

binder, which can be completed just prior to HFST 

application.

• Verify that all distresses identified for treatment in the 

project plans have been addressed or will be 

addressed during installation.

• Verify that bituminous crack sealant material is kept 

flush with or slightly recessed from the top surface of the 

pavement (figure 2) and not overbanded onto the 

pavement surface.

• Allow bituminous crack sealant to cure for at least 30 

days prior to HFST application.
13

© The Transtec Group 

Figure 2. Photograph. Example of bituminous crack sealant in 

asphalt pavement.

Cleaning and Roughening

These processes are used to thoroughly clean and roughen 

the pavement surface to help ensure bond between the 

resin binder and pavement surface.

• Verify that compressed air wash is completed in 

accordance with specifications (AASHTO Specification: 

minimum 180 CFM with tip of lance within 12 inches of 

surface - note that following this specification is not 

required by Federal law or regulation) and that the 

surface is fully covered by the air wash (figure 3).
14

© The Transtec Group 

Figure 3. Photograph. Example of compressed air wash surface 

preparation. 

• Concrete pavement: verify that the specified concrete 

surface profile (CSP) (AASHTO Specification: minimum 

CSP of 5 - note that following this specification is not 

required by Federal law or regulation) has been 

achieved with the shotblasting process (figure 4). Verify 

that entire surface to receive HFST has been 

shotblasted. Ensure that a compressed air wash has 

been used to remove latent dust and verify that the 

prepared surface is free from dust. 

• If a power broom or vacuum truck are used to clean 

the surface, ensure that these are not generating 

additional dust and are followed by a compressed air 

wash to remove latent dust.
15

• For a double layer HFST, verify that all loose aggregate 

has been removed from the first layer before 

application of second layer.

© KwikBond Polymers 

Figure 4. Photograph. Shotblast concrete surface with CSP = 5.

Striping and Pavement Marking Removal 

and Masking

Most pavement markings and striping within the 

boundaries of where HFST is to be applied can be either 

removed or masked prior to HFST application, as directed 

by project plans and specifications. 

• Removal of markings
16

o Verify complete removal of any pavement 

striping or markings as provided in the project 

plans and specifications.

o Check the integrity of the pavement surface 

where the striping/markings were removed to 

verify that there is no damage (e.g., raveling) 

from the removal process (figure 5). 

• Protection of markings

o Verify that any pavement striping or markers to 

be left in place have been properly masked off 

as provided in the project plans and 

specifications.
17

© The Transtec Group 

Figure 5. Photograph. Example of pavement striping removal 

using milling which has not damaged the underlying pavement. 

Protection of Joints and Drainage 

Structures

Protection of working joints (e.g., concrete pavement or at 

bridge abutments) and drainage inlets helps prevent 

intrusion of HFST materials during installation.
18

• Verify that any pavement joints (e.g., concrete 

pavement joints, bridge approach joints, etc.) have 

been masked off as provided in project plans and 

specifications.

• Verify that any drainage structures (e.g., inlets, 

manholes, etc.) have been properly masked off as 

provided in project plans and specifications (figure 6).

© WSDOT 

Figure 6. Photograph. Example of masking of drainage 

structures near HFST application. 
19

Protection of the Prepared Surface Prior to 

Application

Maintaining the integrity of the prepared surface prior to 

HFST application is critical for helping to ensure proper 

bond between the resin binder and pavement surface. 

• Verify that the surface is clean and dry prior to HFST 

application. If the surface has been opened to traffic 

after cleaning and roughening, verify that the surface 

has not been affected by traffic. 

• Check cracks, joints, and surface pores for dirt and 

moisture. 

• Check moisture content of surface if included in 

project specifications. A common method for checking 

moisture content is ASTM D 4263, “Indicating Moisture in 

Concrete by the Plastic Sheet Method,” modified to a 

two-hour test. 

• Monitor prepared surface prior to and during 

installation for any contaminants from installation 

vehicles (oil, hydraulic fluid, air conditioner condensate, 

etc.).
20

HFST 

APPLICATION

Image source: Florida DOT 
21

Application Considerations and Methods

General principles for HFST application inspection, 

regardless of the method include:

• Ensure resin binder is properly proportioned to 

manufacturer specifications for installation conditions 

(pavement and air temperature) and thoroughly 

blended such that it fully cures after application.

• Ensure resin binder is applied to the appropriate mil 

thickness, verified using a wet film thickness gage (if 

appropriate, figure 7) and through a comparison of 

anticipated to actual coverage rate.

• Ensure aggregate is applied to the resin binder before it 

gels and that all resin binder is covered.

• Prevent vehicular traffic on the HFST surface before it 

has cured.

© The Transtec Group 

Figure 7. Photograph. Wet film thickness gage used to measure 

resin binder thickness during application. 
22

The two primary methods for HFST application are manual

and fully-automated. Most agencies require fullyautomated HFST installation, with manual application 

permitted for smaller or irregular areas (less than 200-300 

SY) where automated installation is impractical. Installations 

where lane width varies over the treatment section or 

irregular areas at tapers or turn pockets are examples 

where manual application may need to supplement

automated installation.

Manual Application

Manual application consists of manual processes for resin 

binder proportioning, resin binder blending, resin binder 

application, and aggregate application. While manual 

installations may utilize components, such as automated 

proportioning and blending of resin binder or 

mechanically-assisted placement of aggregate, 

application of the resin binder is typically performed with 

manual labor using notched squeegees to spread the resin 

binder on the pavement surface (figure 8 through figure 

10).
23

© The Transtec Group

Figure 8. Photograph. Example of mechanically-assisted manual 

resin binder application. 
24

© The Transtec Group

Figure 9. Photograph. Example of manual application of 

aggregate, broadcast by hand.

Source: FHWA

Figure 10. Photograph. Example of mechanically-assisted manual 

aggregate application using a venturi blower. 
25

Resin Binder Proportioning and Blending

General list of tools and equipment for manual resin binder 

proportioning and blending (figure 11): 

• Tarps/plastic sheeting to protect work area.

• Nozzles for resin totes.

• Clean measuring containers (resin type dependent).

• Variable speed drill (primary and backup).

• Generator for mixing drill. 

• “Jiffy” style mixer for blending.

• Timer for resin blending.

• Clean mixing container (with wheels if using for 

transport).

• Rags for clean-up and cleaning spills.

Inspection of manual resin binder proportioning and 

blending:

• For manual proportioning and blending, verify that resin 

binder components are proportioned to the correct 

ratio.

• For mechanically-assisted proportioning and blending, 

verify the metering process used to proportion the resin 

binder components to the proper ratio.

• Routinely sample the blended material to ensure that it 

cures/hardens. 
26

© The Transtec Group 

Figure 11. Photograph. Typical tools and equipment for resin 

binder proportioning and mixing for manual application.
27

Resin Binder Application

General list of tools and equipment for manual resin binder 

application:

• Duct tape/tar paper to form start/end joint.

• Wheelbarrow or wheeled mixing container for 

transporting resin from blending to placement location 

(may not be necessary for mechanically-assisted

reason binder proportioning and blending).

• Spiked shoes for squeegee operator to prevent 

shoeprints in resin binder (figure 12).

• Notched rubber squeegee for spreading resin binder 

with provision of additional squeegees for replacement 

when notches/serrations become worn (figure 13).

• Wet film thickness gauge (figure 7). 

Source: FHWA

Figure 12. Photograph. Example of spiked shoes

worn by squeegee operator. 
28

Source: FHWA 

Figure 13. Photograph. Notched rubber squeegee for spreading 

resin binder during manual application.

General list of items for inspection of manual resin binder 

application (figure 14): 

• Note ambient and pavement surface temperatures 

regularly during application. 

• Verify use of tar paper (or similar) masking to create 

clean construction joints at the beginning and end of 

the placement.

• Note resin binder viscosity and if it appears too thick or 

too thin.

o If resin binder is too thick, it may be difficult to 

spready uniformly.

o If resin binder is too thin, watch for resin binder 

sheeting across the lane or down the pavement 

grade leaving deficient thickness at the high side. 
29

• Watch for resin binder running off the lane, potentially 

leaving inadequate thickness. 

• Verify complete coverage of the treated area with 

resin binder before aggregate application.

• Note the method used to operate the squeegee. 

Squeegees are pulled towards the operator rather than 

pushed. 

• Note any changes in color or consistency of resin 

binder throughout application and watch for 

contaminants (e.g., deleterious materials or residual 

hardened resin binder) as resin binder is deposited onto 

the pavement surface. 

• Verify resin binder mil thickness with a wet film thickness 

gage at the frequency prescribed in the project 

specifications.

• Verify total material quantity usage at the end of 

placement for comparison with expected usage based 

on necessary mil thickness.
30

© KwikBond Polymers 

Figure 14. Photograph. Example of manual resin binder 

application. 

Aggregate Application

General list of tools and equipment for manual aggregate 

application:

• Wheelbarrows (2-wheeled preferred).

• Shovels (flat head preferred).

• 5-gallon buckets.

• For mechanically-assisted aggregate application, only 

5-gallon buckets may be necessary. 
31

General list of checks for inspection of manual aggregate 

application (figure 15): 

• Verify that aggregate is applied to the resin binder in 

accordance with the project specifications for timing 

and broadcast height.

• Verify that aggregate is applied using a method that 

does not disturb (shove) the resin binder, ideally from 

the shoulder or adjacent lane. 

• Watch for foreign material and significant dust content 

in aggregate as it is applied.

• Verify that aggregate is applied to the wet resin binder 

before gelling occurs and within the prescribed timing 

from project specifications or manufacturer 

recommendations. 

• Verify that all resin binder is completely covered such 

that no “wet” areas of resin binder show through the 

aggregate before resin gels.

• Verify that aggregate application remains behind resin 

binder application such there is no aggregate on the 

pavement surface before the resin binder. 

• Verify uniform thickness of aggregate application. 

• Verify total material quantity usage at the end of 

placement for comparison with expected usage from 

project specifications
32

© The Transtec Group

Figure 15. Photograph. Example of manual application of HFST 

aggregate. 

Fully-Automated Application

In general terms, fully-automated application consists of a 

single vehicle which is capable of placing HFST in a single 

pass with minimal manual effort. All materials are 

contained on the vehicle, and automated systems for 

conditioning (pre-heating), metering, blending, and 

placing the resin binder and aggregate materials are 

utilized for application of HFST (figure 16 and figure 17). 
33

© The Trasntec Group 

Figure 16. Photograph. Example of a fully-automated installation 

vehicle. 
34

© The Transtec Group

Figure 17. Photograph. Example of resin binder and aggregate 

placement on a fully-automated installation vehicle. 

Resin Binder Application

• Verify functionality of resin binder component metering 

system and proportioning to the proper blending ratio.

• Routinely sample blended material to ensure that it 

cures/hardens.

• Note ambient and pavement surface temperatures 

regularly during application.

• Verify use of tar paper (or similar) masking to create 

clean construction joints at the beginning and end of 

the placement.
35

• Observe resin binder application, noting any issues with 

consistency of the material or uniformity of coverage 

(figure 18).

• Note any excessive use of rollers and squeegees to 

correct automated application issues.

• Verify resin binder mil thickness with a wet film thickness 

gage, if possible, at the frequency prescribed in the 

project specifications.

• Verify total material quantity usage at the end of 

placement for comparison with expected usage based 

on specified mil thickness. 

© Florida DOT

Figure 18. Photograph. Example of fully automated resin binder 

application followed by automated aggregate application 

demonstrating uniformity of coverage. 
36

Aggregate Application

• Verify that aggregate is applied to the resin binder in

accordance with the project specifications for timing 

and broadcast height.

• Verify that aggregate application method does not 

interfere with resin binder application or disturb (shove) 

the resin binder.

• Watch for foreign material and significant dust content 

in aggregate as it is deposited.

• Observe aggregate application, noting any issues with 

uniformity of coverage (figure 18).

• Verify that all resin binder is completely covered such 

that no “wet” areas of resin binder show through the 

aggregate before resin gels, using manual aggregate 

application to cover these areas as needed.

• Verify total material quantity usage at the end of 

placement for comparison with expected usage from 

project specifications.
37

AGGREGATE 

REMOVAL

Image source: The Transtec Group
38

The primary purpose of aggregate removal is to remove 

the loose excess aggregate from the HFST after the resin 

binder has cured. A secondary purpose is to loosen and 

remove lightly bonded aggregate to help minimize the 

amount of shedding over the first few days and weeks after 

opening to traffic.

Methods

Removal of excess aggregate is generally completed using 

some form of a power broom (figure 19), vacuum sweeper 

(figure 20), or combination broom-vacuum. Power brooms 

tend to be most effective and efficient, generally only 

requiring 1 to 2 passes, but may not be possible to use if 

there is risk of sweeping aggregate into adjacent lanes. 

Whenever broom methods are used, only non-metallic, less 

aggressive broom bristles are recommended. If aggregate 

reuse is permitted, vacuum sweepers are generally the 

most efficient method for reclaiming aggregate. However, 

because vacuum sweepers do not agitate the surface like 

power brooms, 3 to 4 passes may be necessary to remove 

all loose aggregate. Agencies may have their own 

requirements for dust mitigation that will require one 

method over another. 
39

© The Transtec Group

Figure 19. Photograph. Example of aggregate removal 

using a power broom. 

© The Transtec Group 

Figure 20. Photograph. Example of aggregate removal 

using a vacuum truck. 
40

Timing

Timing of aggregate removal is critical. If 

sweeping/vacuuming begins before the resin has 

adequately cured, there is risk of pulling aggregate out of 

the resin binder, potentially diminishing the frictional 

properties of the finished surface. Timing of aggregate 

removal will be based on resin binder manufacturer 

guidelines based on the manufacturer’s cure time 

requirements and ambient temperature at placement. 

Deformability of the resin binder is typically used to 

determine timing of sweeping in the field. Note that cure 

time needed before sweeping may be different from that 

needed before opening to traffic. 

Reclamation

If aggregate is to be reused, reclaimed aggregate needs 

to be stored separately from virgin aggregate such that 

they can be remixed in the proper proportions for future 

application. 
41

Inspection

• Verify that equipment used for aggregate removal is 

appropriate and meets project specifications (e.g., 

non-metallic brush bristles, etc.).

• Verify that the sweeping time is in accordance with the 

resin binder manufacturer recommendations, and resin 

cure has been verified before sweeping begins.

• Note any areas where sweeping exposes the resin 

binder or underlying pavement (figure 21). These areas 

should be repaired or replaced. 

• Verify that all loose aggregate has been removed from 

the surface of the HFST before opening to traffic.

• Verify that all aggregate which has migrated onto 

adjacent lanes, paved shoulders, or pavement 

adjacent to the beginning or end of the HFST section 

has been removed (figure 22).

• Verify that reclaimed aggregate is stored separately 

from virgin aggregate. 
42

© The Transtec Group 

Figure 21. Photograph. Example of exposure of underlying 

pavement after sweeping. 

© The Transtec Group 

Figure 22. Photograph. Example of loose aggregate migration 

onto adjacent lanes and shoulders.
43

FINISHED 

SURFACE 

INSPECTION

Image source: The Transtec Group
44

Before opening to traffic, perform a visual inspection on the 

finished surface. Below is a checklist of recommended 

visual inspection practices. 

• Verify that there is no loose aggregate on the HFST 

surface or adjacent surfaces.

• Verify that there are no areas of discoloration that 

could indicate uncured resin or moisture beneath the 

treatment (figure 23).

• Verify that all masking of striping, pavement markers, 

joints, drainage structures, etc. has been removed.

• Identify any areas where HFST is missing (figure 24) or will 

need to be removed and replaced for nonconformance.

• Verify that the surface is safe to open to traffic before 

these repairs are made.

• If surface is not safe to open to traffic, discuss mitigation 

and repair/replacement plan with installer.

• Verify that all striping has been replaced with 

temporary or permanent markings in accordance with 

project plans and specifications. 
45

© The Transtec Group 

Figure 23. Photograph. Example of discoloration indicating 

uncured resin binder. 

© The Transtec Group 

Figure 24. Photograph. Example of areas where HFST is missing 

and will need repair. 
46

ACCEPTANCE 

TESTING 

Image source: The Transtec Group
47

Acceptance testing differs depending on the owner 

agency. In addition to the visual inspection of the finished 

surface discussed above, acceptance testing typically 

includes friction testing, but may also include macrotexture 

testing and pull-off testing. 

Friction Testing

Friction testing may take place before opening to traffic 

but usually happens 14 to 90 days after opening to traffic 

to allow a wear-in period. Agencies with performance 

guarantees may also specify testing during or at the end of 

the performance period.

Test Methods

The most common methods for friction testing are: ASTM 

E274/AASHTO T 242 LWST2,3, which can be performed under 

traffic, and ASTM E 1911 DFT4, which will involve a lane 

closure (note that following these specifications is not 

required by Federal law or regulation). 

2ASTM. (2020). Standard Test Method for Skid Resistance of Paved Surfaces 

Using a Full-Scale Tire. ASTM E274/E274M-15. ASTM International. West 

Conshohocken, PA.

3AASHTO. (2018). Standard Method of Test for Frictional Properties of 

Paved Surfaces Using a Full-Scale Tire. AASHTO T 242-18. Washington, D.C.

4 ASTM. (2020). Standard Test Method for Resistance to Degradation of 

Small-Size Coarse Aggregate by Abrasion and Impact in the Lose Angeles 

Machine. ASTM C131/C131M-20. ASTM International. West Conshohocken, 

PA.
48

Inspection

• Verify the test requirements in the project 

specifications, including timing, number of tests, test 

speed, and friction value for acceptance.

• Verify that the test is performed in accordance with 

project specifications and any ASTM/AASHTO/agencyspecific procedures (note that following these

specifications is not required by Federal law or 

regulation). 

Macrotexture Testing

Macrotexture testing is typically completed at the same 

time as friction testing and is used to measure texture 

depth.

Test Methods

The two most common methods for macrotexture testing 

are stationary methods that will involve a lane closure. The 

ASTM E 965 “Sand Patch” method uses a known volume of 

sand or glass beads to estimate macrotexture depth, 

reported as mean texture depth or MTD5. The ASTM E2157 

Circular Track Meter measures macrotexture over a circular 

path using a laser and reports it as mean profile depth or 

MPD. Note that following these specifications is not 

required by Federal law or regulation. 

5ASTM. (2019b). Standard Test Method for Measuring Pavement 

Macrotexture Depth Using a Volumetric Technique. ASTM E965-15. ASTM 

International. West Conshohocken, PA.
49

Inspection

• Verify the test requirements in the project 

specifications, including timing, number of tests 

required, and friction value for acceptance.

• Verify that the test is performed in accordance with 

project specifications and any ASTM/AASHTO/agencyspecific procedures (note that following these

specifications is not required by Federal law or 

regulation). 

Other Testing

Some agencies may have additional acceptance testing 

procedures, such as the ASTM C1583 pull-off tensile 

strength test to verify adhesion between the HFST and 

underlying pavement6. This is also a stationary test which 

will involve a lane closure but can typically be performed 

after installation, before opening to traffic.

6ASTM. (2020). Standard Test Method for Tensile Strength of Concrete 

Surfaces and the Bond Strength or Tensile Strength of Concrete Repair 

and Overlay Materials by Direct Tension (Pull-off Method). ASTM 

C1583/C1583M-20. ASTM International. West Conshohocken, PA.
50

EARLY-AGE 

MONITORING

Image source: The Transtec Group
51

Early-age monitoring will help identify any issues related to 

materials and installation workmanship. These issues will 

typically develop within the first 30 to 60 days after 

installation.

Uncured Resin Binder

Uncured resin binder will normally appear as isolated areas 

where the HFST is discolored (figure 23) and soft, and will 

lead to aggregate loss or flushing of the resin binder on the 

HFST surface. This may not appear immediately and may 

develop over the first few days after installation. Agencies 

may investigate discoloration and determine the limits of 

the resin binder failure as it may not affect the entire 

application. 

Agencies may remove and reapply the HFST in the 

affected area(s) to correct the resin binder failure.

Aggregate Loss and Re-Sweeping

HFST will naturally shed aggregate that is only lightly 

bonded to the resin binder under traffic wear. Normal 

shedding will generally be heaviest during the first 24 to 72 

hours, tapering off over time, depending on traffic volume. 

Shed aggregate will generally accumulate along the 

edges of the lane and possibly in adjacent lanes and 

paved shoulders (figure 25). Re-sweeping is typically 

included in project specifications to remove this loose 

material within the first 2 to 4 weeks of installation.

If significant aggregate loss continues beyond the first 30 to 

60 days, this may indicate an issue with materials and 
52

installation and the cause should be investigated further, 

particularly if the resin binder or underlying pavement 

becomes exposed.

Corrective action for aggregate loss is removal and 

reapplication of the affected area(s). 

© The Transtec Group 

Figure 25. Photograph. Example of aggregate shedding and 

accumulation along lane edge and on paved shoulder.

Delamination

Delamination is the separation of the HFST from the 

underlying pavement due to a lack of bond. Delamination 

generally manifests as “sheets” of HFST peeling away from 

the surface, commonly in small, localized areas, but can 

spread to much larger areas (figure 26). 
53

Delamination is not obvious until the HFST peels away, 

leaving exposed pavement, but may still be occurring. 

Sounding techniques can be used to identify delamination 

if there is evidence that this may be occurring. 

Corrective action for delamination is removal of all 

affected areas and reapplication of HFST. Widespread 

delamination may necessitate complete removal and 

reapplication, ensuring that any possible causes of the 

delamination (e.g., surface preparation) are addressed 

before reapplication.

© The Transtec Group 

Figure 26. Photograph. Example of delamination of HFST from 

underlying pavement surface. 
54

Aggregate Polishing

Aggregate polishing is the result of aggregate particles 

being worn away under traffic, leaving a smooth HFST 

surface where the aggregate may be worn flush with the 

resin binder (figure 27). While this is not likely to occur if 

calcined bauxite aggregate meeting specifications is 

used, if it does occur, further investigation with laboratory 

testing is warranted.

Corrective action for aggregate polishing will be removal 

and reapplication of the HFST.

© The Transtec Group 

Figure 27. Photograph. Example of polished HFST surface in 

wheelpaths. 
55

Discoloration

Discoloration is a visible difference in color of localized 

areas of HFST from the surrounding surface (figure 28). 

Discoloration does not necessarily indicate a problem with 

the HFST but may be an indicator of the presence of

moisture trapped beneath the HFST. Continue monitoring 

over time to note any changes in discoloration or 

appearance of localized distresses. Corrective action may 

be needed if the condition leads to distresses. 

© The Transtec Group 

Figure 28. Photograph. Example of HFST discoloration likely 

caused by moisture. 
56

Surface Wear Loss of HFST

Surface wear loss of HFST occurs when both the aggregate 

and resin binder wear off under traffic. This generally occurs 

when the aggregate polishes or breaks away from the resin 

binder, exposing the resin binder which quickly wears off, 

exposing underlying pavement (figure 29). While wear-off is 

expected at the end of HFST service life, premature 

wear-off is a cause for concern that should be investigated 

further, as it may indicate that the resin binder layer was 

placed too thin. 

Corrective action for wear-off is reapplication of HFST either 

over the existing surface (if recommended by the resin 

binder manufacturer) or after removal of the worn layer. 

© The Transtec Group 

Figure 29. Photograph. Example of HFST worn off in the 

wheelpaths. 
57

Friction Loss

Friction loss is defined as a sustained decrease in friction 

over time. While there will naturally be some loss of friction 

over the first year after installation as the surface is worn in 

under traffic, continued loss of friction (e.g., 10 percent or 

more) year after year, should be investigated further. 

Generally, this condition is caused by polishing or loss of 

aggregate. 

Corrective action for friction loss is reapplication of HFST 

either over the existing surface (if recommended by the 

resin binder manufacturer) or after removal of the existing 

surface.

Failure of Underlying Pavement

Failure of the underlying pavement will cause a loss of HFST. 

Failures typically manifest as small, isolated areas (e.g., 

potholes) which can progress to much larger areas 

(figure 30). This type of failure is more common in asphalt 

pavements and may be the result of a cohesive failure 

within a weak asphalt layer or due to stripping of the 

asphalt layer due to trapped moisture. 

Corrective action for failure of the underlying pavement 

will involve removal of the affected area, proper repair of 

the underlying pavement, and reapplication of HFST.
58

© The Transtec Group 

Figure 30. Photograph. Example of failure of underlying pavement 

leading to isolated failures (potholes) of HFST. 
59

INSPECTION 

CHECKLIST

Image source: The Transtec Group
60

1 Pre-Construction

Item Item Description Status 

1.1

Review contractor Quality Control Plan (QCP) to verify provisions

for:

a) Test strip and full-scale/production of HFST placement schedule 

(if test strip is to be completed separately).

b) Description of equipment for placing HFST.

c) Methods for conditioning, metering, blending, and applying 

resin binder.

d) Methods for applying aggregate, including timing of placement 

onto resin binder.

e) Methods for monitoring and documenting material usage. 

f) Method for protecting areas that will not receive HFST.

g) Description of acceptable environmental conditions 

(temperature and precipitation) for placing HFST.

h) Cure time and time to opening to traffic estimates for HFST.

i) Storage and handling of HFST materials.

j) Disposal and recycling of excess HFST and containers.

k) Contingency plan for possible failure during the HFST 

application.

l) Name of the certified independent testing laboratory.

m) Key personnel and contact information.

n) All project certifications and test results.

1.2 Verify name and contact information for contractor QCP 

administrator. 

1.3

Check that materials supplied to the project meet project 

specification requirements (through agency testing or from 

certified test results from the installer).

1.4 Verify that a resin binder manufacturer’s representative is present 

for initial/test strip installation.
61

2 Materials

Item Item Description Status 

2.1 Check that resin binder is type and brand specified in the QCP.

2.2 Check that aggregate material is type and brand specified in 

QCP.

2.3

For reclaimed aggregate only: verify that reclaimed material had 

been blended with new/virgin material at the specified ratio (e.g., 

two parts new to one part reclaimed). 

2.4

Check resin binder and aggregate stockpiles to verify proper 

packaging and storage of materials.

2.5

Check that aggregate is clean (minimal dust content and no 

foreign materials) and dry (subjective assessment). 

2.6

Check that adequate quantities of resin binder and aggregate 

materials for the intended installation area are on-site or accessible 

near the project site. 

2.7 Sample materials for verification testing on-site as provided by 

specification.
62

3 Surface Preparation

Item Item Description Status 

3.1 Check that all distresses identified for pre-treatment in the project 

plans have been addressed. 

3.2

Check that all striping and pavement markings have been 

removed or masked as required in project plans and 

specifications.

3.3

Check that all drainage inlets, manhole and valve covers, and 

other utilities and structures have been masked as required in 

project plans and specifications.

3.4

Shotblasting: Verify that surface has been shotblast to concrete 

surface profile (CSP) of 5, as required in project specifications, 

followed by compressed air wash.

3.5

Check that entire surface has been cleaned with a mechanical 

sweeper and/or a compressed air wash as required in the project 

plans.

3.6

Check that all pavement surfaces to be covered with HFST are dry 

and free of oils, grease, dust (including latent dust from 

shotblasting) and foreign material prior to HFST placement.
63

4 Pre-Application

Item Item Description Status 

4.1 Verify test strip placement procedure (i.e., separate test strip or as 

part of initial production installation).

4.2 Check that equipment for placing HFST is as outlined in the QCP.

4.3 Document width of placement based on installation vehicle setup.

4.4 Check for masked-off areas at beginning and end of placement 

to ensure clean termination joints.

4.5 Verify that resin binder metering devices are fully functional.

4.6

Document ambient and surface temperatures at start and end of 

application (minimum) and routinely throughout application if 

necessary. 
64

5 Resin Binder Application

Item Item Description Status 

5.1 Check for changes in coloration and consistency of resin binder 

throughout application.

5.2 Check uniformity of resin binder film across the lane (e.g., no gaps 

or tearing of the film or variations in thickness).

5.3 Check thickness of resin binder on pavement surface as it is placed 

using a mil thickness gage as required in project specifications.

5.4

Document total quantity of material used from metering devices 

on installation vehicle. Verify if quantity of material used 

corresponds to anticipated quantity based on placement area 

and mil thickness requirement.

5.5

Manual application of small areas:

a) Check that resin binder is properly proportioned and thoroughly 

blended before being deposited on pavement surface.

b) Check that resin binder is spread with notched squeegees to 

the uniform thickness specified in the project requirements over the 

placement area.

c) Check that resin binder is not sheeting or running across the lane 

or down the pavement grade before aggregate is applied.

d) Check that no foot traffic other than spiked shoes are allowed 

on uncovered resin binder.

5.6 Check that no vehicular traffic is allowed onto the surface prior to 

curing of the resin binder.
65

6 Aggregate Application

Item Item Description Status 

6.1 Check that aggregate is applied onto the resin binder within the 

time required in the project specifications.

6.2 Check that aggregate is applied in a manner that it does not 

disturb the resin binder

6.3 Check for dryness and cleanliness (substantially free of dust and 

foreign matter) of aggregate as it is deposited.

6.4 Check for uniformity of placement across the lane.

6.5 Check for aggregate placement until refusal over resin binder.

6.6 Check that any exposed resin binder and “wet” areas that appear 

are covered.

6.7

Document total quantity of material used from installer records. 

Verify if quantity of material used corresponds to anticipated 

quantity based on placement area.

6.8

Manual Placement of small areas:

a) Check that aggregate is deposited onto the exposed resin 

binder within the time required in the project specifications.

b) Check that aggregate is broadcast such that it does not disturb 

the resin binder.
66

7 Aggregate Removal

Item Item Description Status 

7.1 Check that resin binder has reached adequate cure prior to 

sweeping (verify that resin binder is not soft and that aggregate 

does not pull out of resin binder).

7.2 Document timing of aggregate removal with respect to 

completion of HFST placement.

7.3

Check that aggregate removal using a vacuum or power brooms 

is not damaging the HFST surface and exposing the underlying 

pavement.

7.4 Check that surface is free of loose aggregate after completion of 

all aggregate removal.

7.5 Check for and document any areas where underlying pavement is 

exposed after aggregate removal.
67

8 Opening to Traffic and Acceptance Testing

Item Item Description Status 

8.1 Check for any remaining loose aggregate.

8.2 Check for any “soft” areas in the HFST surface where resin binder 

may not have fully cured.

8.3 Check for and document any discolored areas in HFST surface.

8.4 Check for and document any areas where HFST is missing and 

needs to be patched.

8.5 Check for replacement of pavement markings (temporary or 

permanent) as required in the project plans and specifications.

8.6 Verify that masking has been removed from drainage inlets, 

manhole and valve covers.

8.7

Check for loose aggregate on any adjacent untreated lanes and 

paved shoulders, and untreated pavement before and after the 

treated area.

8.8

Verify the plan for acceptance testing and check that 

acceptance testing is performed in accordance with project 

specifications. 

8.9 Check acceptance testing result for conformance with project 

specifications. 

9 Post-Installation

Item Item Description Status 

9.1

Monitor aggregate shedding over the first several days after 

installation and note any excessive build-up of loose aggregate 

within the treated lanes or on adjacent surfaces. Ensure loose 

aggregate is promptly removed if it presents a safety hazard.

9.2 Check that surface is re-swept within two weeks after initial 

placement to remove loose aggregate.

9.3 Monitor the HFST surface for discoloration, delamination, cracking, 

and other distresses.
68

ADDITIONAL 

RESOURCES

Image source: The Transtec Group
69

FHWA Frequently Asked Questions for HFST

https://safety.fhwa.dot.gov/roadway_dept/pavement_

friction/faqs_links_other/hfst_faqs/

FHWA Technical Advisory for Pavement Friction 

Management (T 5040.38)

https://www.fhwa.dot.gov/pavement/t504038.cfm

FHWA Office of Safety HFST website 

https://safety.fhwa.dot.gov/roadway_dept/pavement_

friction/high_friction/

FHWA/ATSSA Videos

6 min. version: https://www.youtube.com/

watch?v=HVzS-VkABPE

20 min. version: https://www.youtube.com/

watch?v=V860pC6ncAY

ATSSA HFST Technical Services 

https://www.atssa.com/Technical-Services/HighFriction-Surface-Treatment

ATSSA HFST Inspection and Installation Training Course

https://www.atssa.com/Training/Find-a-Course/HighFriction-Surface-Treatment-Inspection-andInstallation#/qbeld/Web_HFS_Events

Pennsylvania DOT HFST Videos

https://www.youtube.com/watch?v=YE5N8WiAp24

https://www.youtube.com/watch?v=Sn34DAynjCE

Oklahoma DOT HFST Video

https://www.youtube.com/watch?v=gWajb4Vz38Q

Florida DOT High Friction Surface Treatment Guidelines 

https://www.fdot.gov/docs/default-source/materials

/pavement/performance/ndt/documents/

hfstguidelines.pdf
 

FHWA-SA-22-15

Image source: The Transtec Group