BACKGROUND

High friction surface treatment (HFST) is a proven Federal Highway Administration (FHWA) safety countermeasure applied to pavements to significantly increase texture and skid resistance at critical locations, such as sharp curves, ramps, intersections, steep gradients, and pedestrian crossings, particularly in wet conditions. However, current HFST technologies tend to be expensive due to the use of specialized, high-quality aggregates, such as calcined bauxite and premium binders.

Research is needed to explore alternative binder technologies (e.g., emulsified asphalt) and aggregate types to develop novel HFSTs with lower life cycle costs and equal or better performance to traditional HFSTs that use polymer binder (e.g., epoxy resin) and calcined bauxite aggregates.

OBJECTIVE

The objective of this project is to develop guidelines for using engineered asphalt emulsion-based HFSTs that achieve the same performance as traditional HFSTs. At a minimum, the research will assess the technical and economic feasibility of using engineered asphalt emulsion-based HFST.

Accomplishment of the project objective will require at least the following tasks.

TASKS

PHASE I – Planning

Task 1. Conduct a literature review of traditional and novel HFSTs, with particular emphasis on the use of asphalt binders and emulsions. Key aspects to cover include application methodologies, durability, and the performance of these treatments under varying environmental and loading conditions. The review shall include published and unpublished documentation, past surveys, and research conducted through the NCHRP; the FHWA; other national, state, and local agencies; international organizations; and contacts with public and private organizations, material manufacturers, and suppliers.

Task 2. Survey state departments of transportation and material manufacturers and suppliers. Conduct follow-up interviews with selected stakeholders to gather information about available novel HFSTs that use asphalt emulsion, binders, and domestically sourced aggregate alternatives.

Task 3. Identify knowledge gaps related to the project objective based on the review and survey performed in Tasks 1 and 2. These gaps should be addressed in the final product or the recommended future research, as the budget permits.

Task 4. Propose the research plan to be executed in Phase II to achieve the project objective. At a minimum, the research plan shall include the following:

1. Representative selections of novel HFST technologies, including various engineered asphalt emulsions and aggregate types as well as a traditional epoxy-based HFST. The study should prioritize the use of calcined bauxite before considering other aggregates.
2. A framework for comparing the performance (e.g., aggregate retention, binder adhesion, texture, and skid resistance) of traditional and novel HFSTs in the laboratory and field (see Special Note A). The evaluation shall focus on the performance of HFSTs under normal wear and tear, at varying load levels (e.g., high- and low-volume roads), and in various climatic conditions. The field study shall be conducted on various pavement types that are either in good or excellent condition.
3. A procedure for a life cycle cost analysis of various HFSTs using different materials (e.g., asphalt emulsions, asphalt binders, multiple aggregates, etc.).
4. A process to develop the draft language for the recommended guidelines for (1) material selection and mix design, (2) construction practices, (3) performance testing, and (4) quality assurance for using asphalt emulsion-based HFST (see Special Note B).

Task 5. Prepare Interim Report No. 1, which documents the research performed in Tasks 1 through 4 and provides an updated work plan for the remainder of the research no later than 6 months after the contract is awarded. The updated plan must describe the process and rationale for the work proposed for Phases II and III. 

PHASE II – Execution

Task 6. Execute the work plan according to the approved Interim Report No.1.

Task 7. Prepare and submit a preliminary draft of the AASHTO Deliverables based on the results of this work.

Task 8. Prepare Interim Report No. 2, which documents Tasks 6 and 7 and provides an updated work plan for the remainder of the research no later than 22 months after the approval of Phase I. The revised plan must describe the process and rationale for the work proposed for Phase III.

PHASE III – Final Deliverables

Task 9. Review and consider the comments on the preliminary draft of the AASHTO Deliverables and prepare a revised draft version of the AASHTO Deliverables.

Task 10. Present the research findings to appropriate AASHTO technical committees to collect comments for potential revisions to the AASHTO Deliverables. Update the AASHTO Deliverables based on the comments (see Special Note C). 

Task 11. Prepare a stand-alone technical memorandum titled “Implementation of Research Findings and Products”.

Task 12. Prepare presentation material, in a PowerPoint or other format, for use in webinars to facilitate the use and adoption of the AASHTO Deliverables.

Task 13. Submit the final deliverables, including (1) a final report documenting the entire research effort, (2) the AASHTO Deliverables, (3) the Implementation of Research Findings and Products, and (4) the presentation materials.

STATUS: Proposals have been received in response to the RFP. The project panel will meet to select a contractor to perform the work.