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. 

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. 
iii

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

116 

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.
vi 

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.
vii 

Quality Assurance Statement 

The Federal Highway Administration 

(FHWA) provides high-quality 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.
viii

CONTENTS

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

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

Applications and Precautions........................................ 4

HFST Installation ................................................................ 6

PRE-CONSTRUCTION ........................................................... 7

Quality Control Plan (QCP) .............................................. 8

QCP Administrator.........................................................10

Materials Verification ......................................................11

HFST MATERIALS ................................................................ 12

Resin Binder ......................................................................13

Calcined Bauxite Aggregate.........................................15

SURFACE PREPARATION .................................................... 18

Treatment of Pavement Distresses................................. 19

Cleaning and Roughening.............................................21

Striping and Pavement Marking Removal and Masking

...........................................................................................25

Protection of Joints and Drainage Structures ..............28

Protection of the Prepared Surface Prior to Application

...........................................................................................29

HFST APPLICATION ............................................................. 31

Application Considerations and Methods...................32
ix

Manual Application ........................................................34

Resin Binder Proportioning and Blending....................38

Resin Binder Application ...............................................40

Aggregate Application ................................................46

Fully-Automated Application.........................................49

Resin Binder Application ...............................................51

Aggregate Application ................................................54

AGGREGATE REMOVAL .................................................... 56

Methods ............................................................................57

Timing ................................................................................60

Reclamation.....................................................................61

Inspection.........................................................................62

FINISHED SURFACE INSPECTION ....................................... 65

ACCEPTANCE TESTING ...................................................... 69

Friction Testing..................................................................70

Test Methods ..................................................................70

Inspection .......................................................................71

Macrotexture Testing ......................................................72

Test Methods ..................................................................72

Inspection .......................................................................73

Other Testing ....................................................................75

EARLY-AGE MONITORING ................................................ 76

Uncured Resin Binder ......................................................77
x 

Aggregate Loss and Re-Sweeping ...............................78

Delamination....................................................................80

Aggregate Polishing........................................................82

Discoloration ....................................................................84

Surface Wear Loss of HFST ..............................................85

Friction Loss.......................................................................87

Failure of Underlying Pavement.....................................88

INSPECTION CHECKLIST ..................................................... 90

ADDITIONAL RESOURCES ................................................ 103
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 friction-related 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 
3 

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 Crash-Modification Factors for High-Friction 

Surface Treatments: Friction Change Report. Federal 

Highway Administration FHWA Research Report FHWAHRT-20-062. McLean, VA.
4 

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 
5 

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.
6 

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
7 

PRE- CONSTRUCTION

Image source: The Transtec Group
8 

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 fullscale/production of HFST placement (if 

test strip is to be completed 

separately).
9 

• 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.
10 

• Contingency plan for possible failure 

during the HFST application.

• Name of the certified independent 

testing laboratory.

• 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. 
11 

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. 
12 

HFST 

MATERIALS

Image source: The Transtec Group
13 

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.
14 

• 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. 
15 

• Verify that adequate quantities of resin 

binder components for the intended 

installation are on-site or accessible 

near the project site.

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 
16 

on-site or accessible near the project 

site.

• Sample materials for verification testing 

on-site as called for by specification. 

• Assess aggregate cleanliness:

oExamine aggregate material in 

packaging or installation vehicle for 

presence of foreign matter.

oObserve loading of aggregate into 

installation vehicle to check for 

segregation and assess cleanliness 

(dust generation). 

oVerify 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.

oIf reclaimed aggregate is permitted, 

verify that reclaimed material has 
17 

been remixed with virgin material at 

the specified minimum ratio 

(typically 2:1 or 3:1 virgin to 

reclaimed). 
18 

SURFACE 

PREPARATION

Image source: The Transtec Group
19 

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 

non-working cracks wider than 0.25 inches 
20 

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.
21 

© 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 
22 

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).
23 

© 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 
24 

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.

• For a double layer HFST, verify that all 

loose aggregate has been removed 

from the first layer before application of 

second layer. 
25 

© 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 
26 

be applied can be either removed or 

masked prior to HFST application, as 

directed by project plans and 

specifications. 

• Removal of markings

oVerify complete removal of any 

pavement striping or markings as 

provided in the project plans and 

specifications. 

oCheck 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

oVerify that any pavement striping or 

markers to be left in place have been 

properly masked off as provided in the 

project plans and specifications.
27 

© The Transtec Group 

Figure 5. Photograph. Example of 

pavement striping removal using milling 

which has not damaged the underlying 

pavement.
28 

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.

• 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). 
29 

© WSDOT 

Figure 6. Photograph. Example of masking 

of drainage structures near HFST 

application.

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 
30 

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.).
31 

HFST 

APPLICATION

Image source: Florida DOT
32 

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.
33 

• 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. 
34 

The two primary methods for HFST 

application are manual and fullyautomated. 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 
35 

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). 
36 

© The Transtec Group 

Figure 8. Photograph. Example of 

mechanically-assisted manual resin binder

application. 
37 

© 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. 
38 

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.
39 

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. 
40 

© The Transtec Group 

Figure 11. Photograph. Typical tools and 

equipment for resin binder proportioning 

and mixing for manual application.

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 
41 

not be necessary for mechanicallyassisted 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). 
42 

Source: FHWA

Figure 12. Photograph. Example of spiked 

shoes worn by squeegee operator.

Source: FHWA 

Figure 13. Photograph. Notched rubber 

squeegee for spreading resin binder 

during manual application.
43 

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.

oIf resin binder is too thick, it may be 

difficult to spready uniformly.

oIf 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. 
44 

• 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. 
45 

• Verify total material quantity usage at 

the end of placement for comparison 

with expected usage based on 

necessary mil thickness. 

© KwikBond Polymers 

Figure 14. Photograph. Example of manual 

resin binder application.
46 

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. 
47 

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. 
48 

• 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
49 

© 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 
50 

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). 

© The Trasntec Group 

Figure 16. Photograph. Example of a fullyautomated installation vehicle.
51 

© 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.
52 

• 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.

• 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 
53 

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.
54 

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 
55 

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. 
56 

AGGREGATE 

REMOVAL

Image source: The Transtec Group
57 

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 broomvacuum. 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 
58 

broom methods are used, only nonmetallic, 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. 
59 

© 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. 
60 

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. 
61 

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. 
62 

Inspection 

• Verify that equipment used for 

aggregate removal is appropriate and 

meets project specifications (e.g., nonmetallic 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. 
63 

• 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. 
64 

© 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.
65 

FINISHED 

SURFACE 

INSPECTION

Image source: The Transtec Group
66 

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 non-conformance. 

• Verify that the surface is safe to open to 

traffic before these repairs are made.
67 

• 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. 

© The Transtec Group 

Figure 23. Photograph. Example of 

discoloration indicating uncured resin 

binder.
68 

© The Transtec Group 

Figure 24. Photograph. Example of areas 

where HFST is missing and will need repair.
69 

ACCEPTANCE 

TESTING

Image source: The Transtec Group
70 

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 pulloff 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 
71 

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). 

Inspection 

• Verify the test requirements in the project 

specifications, including timing, number 

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.
72 

of tests, test speed, and friction value for 

acceptance.

• Verify that the test is performed in 

accordance with project specifications 

and any ASTM/AASHTO/agency-specific 

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 
73 

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. 

Inspection 

• Verify the test requirements in the project 

specifications, including timing, number 

of tests required, and friction value for 

acceptance.

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

Pavement Macrotexture Depth Using a Volumetric 

Technique. ASTM E965-15. ASTM International. West 

Conshohocken, PA.
74 

• Verify that the test is performed in 

accordance with project specifications 

and any ASTM/AASHTO/agency-specific 

procedures (note that following these

specifications is not required by Federal 

law or regulation). 
75 

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/C1583M20. ASTM International. West Conshohocken, PA.
76 

EARLY-AGE 

MONITORING

Image source: The Transtec Group
77 

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. 
78 

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.
79 

If significant aggregate loss continues 

beyond the first 30 to 60 days, this may 

indicate an issue with materials and 

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). 
80 

© 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 
81 

from the surface, commonly in small, 

localized areas, but can spread to much 

larger areas (figure 26). 

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.
82 

© The Transtec Group 

Figure 26. Photograph. Example of 

delamination of HFST from underlying 

pavement surface. 

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). 
83 

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.
84 

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. 
85 

© The Transtec Group 

Figure 28. Photograph. Example of HFST 

discoloration likely caused by moisture.

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 
86 

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. 
87 

© The Transtec Group 

Figure 29. Photograph. Example of HFST 

worn off in the wheelpaths. 

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 
88 

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 
89 

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.

© The Transtec Group 

Figure 30. Photograph. Example of failure 

of underlying pavement leading to 

isolated failures (potholes) of HFST. 
90 

INSPECTION 

CHECKLIST

Image source: The Transtec Group
91 

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. 
92 

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.
93 

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 onsite as provided by specification.
94 

3 Surface Preparation

Item Item Description Status

3.1

Check that all distresses identified for pretreatment 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.
95 

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.

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. 
96 

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 
97 

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.
98 

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.
99 

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.
100 

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.
101 

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. 
102 

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.
103 

ADDITIONAL 

RESOURCES

Image source: The Transtec Group
104 

FHWA Frequently Asked Questions for 

HFST 

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

ment_friction/faqs_links_other/hfst_faqs/

FHWA Technical Advisory for 

Pavement Friction Management (T 

5040.38)

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

m

FHWA Office of Safety HFST website 

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

ment_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
105 

ATSSA HFST Inspection and Installation 

Training Course 

https://www.atssa.com/Training/Find-a-Course/

High-Friction-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=gWajb4Vz3

8Q

Florida DOT High Friction Surface 

Treatment Guidelines 

https://www.fdot.gov/docs/defaultsource/materials/pavement/performance/ndt/d

ocuments/hfstguidelines.pdf
 

FHWA-SA-22-15

Image source: The Transtec Group